How Understanding Carbon Cycling Can Transform Your Farm Cattle graze a green cover crop to provide the resources that next year’s cash crop will need in order to grow without synthetic inputs. BY LAUREN KRIZANSKY Manipulation. The word stirs up images of clever characters or bodies twisted on a chiropractor’s table, not of farmers examining the soil. This art of deliberate control, however, is becoming deeply connected to agriculture, and the practice is giving farmers a fresh relationship with the carbon cycle. Agriculture removes large amounts of carbon from the cycle in the form of food. Replenishing the carbon in this part of the cycle is possible, but modern crop production methods have stifled the flow. Linear carbon management in the fields has tipped the scales, taking the carbon exchanges out of balance. The quest for high yields with synthetic inputs has made agriculture the villain it ought not be. “An amount of carbon always comes into the soil, and an amount always leaves the soil,” said Joel Williams, an independent plant and soil health educator working internationally to improve food and farm systems. “The question is how can we manipulate micro-organisms, how can we manipulate our management with each pass of that loop to capture a little bit and keep it in the soil and release the rest that feeds into the cycle?” On farms and ranches, carbon is primarily lost through mismanaged tillage, erosion, burning, overgrazing and frequent low-carbon crops. These same tools are also critical to balance out the carbon cycle. When carbon becomes the cash crop and a living system becomes the priority, agriculture can manipulate the cycle for the better. “In order to sequester, you have to strengthen the cycle,” Williams said. “There is nothing wrong with releasing carbon from soils. That is completely normal. That is what helps plants breath. It is to the extent that we have done this that it has become out of balance.” In agricultural systems, carbon plays four parts. Retired North Dakota-based USDA-NRCS Soil Health Specialist Jay Fuhrer explained how the element moves through a corn crop. It begins, he said, with the harvest and the third of the crop’s carbon that is found in the grain. “We usually put tires under this part,” Fuhrer said. “Exporting 100 percent of this portion for people food, energy or livestock feed.” The second part considers that one third of the crop’s carbon is in the residue, of which upwards of 85 percent is oxidized into the atmosphere. The remaining third of the crop’s carbon is in the root mass, where about 70 percent is no longer available to the agricultural cycle. The fourth part of carbon’s role in agriculture is found in the root exudates of a young, growing, green plant, he said. The soil food web consumes this resource for energy to complete its tasks, especially during the first one to two months of growth. “The microorganisms are carbon hungry,” Williams confirmed. “We need to bring carbon into soils to feed microorganisms to drive nutrient cycling, which then drives production. We need those microorganisms to be releasing that carbon, to be respiring.” This is what the farmer can do to support the efficiency, the health and the connectivity of the carbon cycle. Agriculture can feed not just the people, but the life that begets human life. It can look beyond just transferring atmospheric carbon dioxide into long-lived pools. An example of healthy root mass. Under Cover Carbon Contrary to their reputation, fallow lands do not restore fertility in a crop rotation. When a farmer decides to remove plants from the field, he or she also chooses to have a counterproductive interaction with the carbon cycle. “One is maintaining the carbon cycle when we have living cover,” Williams said. “You are maintaining that flow. When you have a fallow period, you are not. Typically, you are going to be losing carbon.” Fallow lands result in chemical oxidizing, he explained, because the sun is cooking the ground. “Fallow is turning it off,” Williams said. “Cover crops are engaging with the carbon cycle through photosynthesis.” Cover crops contribute to the carbon cycle through a diverse network of specialized personnel underground. They fill the carbon gap that fallow lands and commodity crops leave behind. “When we use cover crops we are feeding the soil system for a greater time throughout the year, and we start a soil-building process through biology,” said Lance Gunderson, president and co-owner of ReGen Ag Labs in Pleasanton, Nebraska. “Remember that soil without biology is called dirt, and that is geology. When we do fallow, we are creating dirt, because we are not supporting the biology that supports our crops.” Gunderson believes that fallow fields are more detrimental to soil than tillage, but it is a combination of the two practices that creates serious problems. “Yes, we should reduce tillage when possible, but I have seen far too many long-term, twenty-plus year, no-till fields exhibit many of the same symptoms of a poor soil as those seen in conventional systems,” he said. “It all boils down to a lack of carbon and diversity.” Bringing carbon into a cropping system through cover crops entices the carbon cycle to sustain the microbial life under the ground that performs many tasks that improve the soil’s health. This manipulation of carbon also contributes to the cash crop that will find its way into the cover cropped fields in coming seasons. “Carbon is the backbone for providing structure to the soil,” Gunderson stressed. “Plants exude a relatively large portion of their photosynthate carbon into the soil through the roots. These root exudates help aggregate the soil both directly and indirectly as food for microbes.” The simple compounds are then used as a food source, he said. The well-fed microbes are then able to produce many secondary compounds that act as a glue to hold soil particles together. “I like to think of it as the mortar that helps hold together the bricks of our homes and businesses,” Gunderson said. “The microbes are building and altering their habitat through the use of carbon.” The stronger and more available the underground habitat, the more productive the microbiology are, for example, in building immunity. Williams said soils rich in carbon, or, more specifically, soil organic matter, are consistently found to possess mechanisms of pathogen suppression. “There is a highly specific interaction between a couple of organisms between the pathogen and some other beneficial microbes, bacteria or fungi that attack the disease,” Williams explained. “There are many unknowns, which is why we maximize diversity in the hopes that some of those antagonistic species will be present.” Fuhrer added, “It really is about food and a home. By providing a diversity of plants, we help maintain and encourage the diversity of microbes and the balance. Allowing the microbe community to self-regulate, which our cropping and grazing systems benefit from by reduced disease impacts.” A seeded potato field after a season of fallow. Water is not moving into the soil. When Cycles Collide Carbon is at the center of the water cycle. Although soil texture plays a role in water dynamics, Gunderson explained that the amount of carbon within a certain textural class also has a profound effect. Increasing soil carbon increases soil aggregation, which increases infiltration. Increases in carbon also reduce bulk density or increase the pore space between aggregates to allow for greater water holding capacity. “Carbon itself can act as a sponge to increase water holding capacity as well,” Gunderson said. “Some people might be thinking that they have too much water or that their soils are too wet, so why increase carbon? Increasing soil structure allows for better drainage throughout the root zone, but it also helps with better gas exchange at the surface, which can moderate soil moisture in wetter environments.” Increasing the functions of the water cycle means being able to capture every drop, hold that water and allow roots to explore the entire soil profile, he added. All of these lead to better water use efficiency and help increase photosynthetic capacity. When considering carbon in the form of soil organic matter, there is an opportunity for the system to hold onto moisture and possibly to help the plant access water, Williams said. Water will infiltrate and photosynthesis will take place. Amplifying the Cycle Livestock is yet another tool to manipulate carbon. “The act of grazing itself, if managed properly, can stimulate plants to produce greater root mass and increase root exudation to increase soil carbon,” Gunderson said. “Grazing also helps reduce many of the higher carbon or more lignified plants into readily accessible forms to speed up nutrient and carbon cycling by secondary consumers such as macroinvertebrates and microbes.” Grazing also removes very few nutrients compared to haying or silage operations, and the additional manure and urine help support soil habitat while recycling the nutrients back to the land. It increases root exudation and increases feeding microbes and nutrient cycling so the pasture can recover and regrow. “Plants which are grazed respond differently,” Williams added. “They can boost their photosynthetic capacity.”The grazed material is put through digestion of the animal’s rumen and spit out in its manure. The rumen does the work, making more nutrients available to the microorganisms in the soil. “They are more palatable to the microorganisms,” Williams said. “They can digest it easier. Wherever animals are included in cropping systems [and] farming systems, that soil organic matter increases.” Fuhrer added, “Our soils evolved with a diversity of plants, animals and microbes. Consequently, we need a diversity of livestock on our landscapes.” When hooves on the ground isn’t an option, compost or manure spreading is often used to fill this need. Control of this input is critical, too. “Manipulation,” echoed Mark Inness, a veteran composter in southern Colorado “[is] the difference between good compost and manure.” His belief in maturity time and pile turns result in balanced proportions of carbon for energy and nitrogen for protein production. If the C:N ratio is too high, excess carbon decomposition slows down. If the C:N ratio is too low excess nitrogen, the compost pile will have management challenges. Compost manipulation also influences the amount of moisture present and conductivity. Moisture affects handling and transport. A desirable moisture content ranges between 40 and 50 percent. Conductivity or soluble salts measures the conductance of electrical current in a liquid-compost slurry. Excessive soluble salt content in a compost can hinder seed germination and proper root growth. Land managers have a choice for how they manipulate the carbon cycle. In addition to the actual tools available to make practical changes, there are also resources to champion a greater shift to carbon-conscious agriculture “As a society, we ask a lot from our farmers and ranchers, often with very little thanks or appreciation,” Gunderson said. “I don’t think that we should expect them to do this alone. We need the right support groups and organizations in place to help and support them in making this a reality. I believe, however, that agriculture could have a greater positive impact on the carbon cycle as a whole than nearly any other industry.” Lauren Krizansky is an agricultural journeywoman. She loves, lives and works with her partner, Brendon Rockey, on Rockey Farms in Center, Colorado.
Feed the Soil, the Plant and the Leaf: The Principles of Fertility By JON FRANK During my first year making fertility recommendations for gardens, I made a wrong assumption. I had witnessed the steady fertility gains made in row crops with relatively modest fertility inputs. I copied what was working in row crops to the newly developed garden program and was surprised to find a failure in the making. The level of reserve fertility was in significant decline – especially calcium and trace minerals. To compensate, I had to dramatically increase the nutrients I recommended, and that fixed the problem. Vegetables remove far more earth minerals that grains, pastures and fruit trees – by a factor of 2-10 times. This difference in crop removal has to be accounted for by increasing fertility inputs. As I learned the principles of Reams teaching, I began to make a connection. Everything he taught in the abstract with detailed theory ultimately led to specific actions and inputs. What started in the theoretical always ended up with practical application. After more time listening to Dr. Carey Reams’ audio courses, it dawned on me that all these actions and inputs could be consigned to three basic ideas. • Feed the Soil• Feed the Plant• Feed the Leaf Feed the Soil is about optimizing soil toward an ideal pattern. Feed the Plant is about giving a helping hand to the microbe/plant root barter system. Feed the Leaf is about foliar nutrition to further enhance yield and to deliver trace minerals. The greatest success in Reams Agriculture comes when all three “buckets” are used in a complete program. Without a doubt, the greatest quantity of inputs is needed to Feed the Soil. The other buckets take far fewer inputs. The rest of this article will discuss the inputs needed to Feed the Soil. But first let’s address the question of why. Why use inputs? Because the proper use of inputs, with the help of plants and microbes, completely changes the pattern of the soil. Imagine a chef commissioned to make the world’s best chocolate cake in less than four hours. What is he going to do? First, he is going to find the very best chocolate cake recipe, then he his going to assemble the finest ingredients, and lastly he is going to follow the recipe meticulously. The highest-quality cake is made with very specific levels of ingredients in very tight ratio with each other. Anything added too much or little or out of balance with other ingredients can completely ruin the cake. Just triple the salt and baking soda and the cake is not fit to eat. The same with soil. Instead of calling it a recipe, we call it a pattern. The pattern of soil is determined by the levels and ratios of available minerals. If we want a better output of high-quality crops or nutrient-dense foods, then we must create the proper pattern in soil. You can’t get a prize-winning cake with a lousy recipe, and neither can you achieve nutrient-dense produce with deficient or imbalanced soil. You have to meet nature’s requirements if you want top quality. Let’s illustrate this with a typical soil test followed up by a decode of the soil pattern, shown in the image above. All nutrients are in pounds per acre on the Morgan soil test. To calculate the ratio, take the lab result for the first nutrient and divide it by the lab result of the second nutrient. To calculate the calcium to magnesium ratio, divide 900 by 125 to get 7.2. This soil has a Ca:Ma ratio of 7.2:1. This general pattern is found all over the south and the eastern third of the United States. But in many instances the soils have even less fertility than this example. So, what does this pattern tell us? Here is the decode. • 16 lbs. of available phosphorous indicates low Brix and poor energy production in the plant. The energy cycle in plants depends on phosphorous, since it is the P in ATP.• 290 lbs. of potassium signifies there will be a crop.• Calcium at 900 lbs. means low yield, very poor root development, and inadequate feeding of soil microbes. Inputs to help the microbes are needed.• Magnesium at 125 lbs. is a sufficient amount for leaf function, but still low.• The P:K ratio of 0.05:1 indicates broadleaf weed pressure.• The Ca:Ma ratio of 7.2:1 indicates a soil that is workable and not sticky.• The extreme Ca:P ratio of 196:1 further highlights how critically low phosphorous is and suggests insect and disease susceptibility. If copper is also low and the year is wet, you might see a fungal attack.• The Ca:K ratio of 3:1 is the other extreme. Such a high level of potassium relative to calcium indicates poor cellular integrity of the crop. This happens when potassium substitutes for calcium in the cell walls.Altogether, this is the pattern of a depleted soil. This soil can not produce high Brix or nutrient-dense food or crops in the near future. Animals eating forages grown on this soil will not perform well. The good news is that this soil is easy to fix. The bad news is that it is not cheap.Inputs to grow the upcoming crop and improve the overall soil pattern could include the following:• Soft rock phosphate• Low-magnesium limestone• 11-52-0 mono-ammonium phosphate• Calcium nitrate• Epsom saltWhat is not suggested for this year is an application of compost or manure. They should be avoided because potassium will increase, and it is already too high.A complete feeding to the soil will impact roots and microbes. As the pattern changes toward ideal crop health, yield improves, and so does the nourishment of people and animals.Next month we will cover the inputs to Feed the Plant and Feed the Leaf. In the meantime, I hope you are enjoying a diet of nutrient-dense foods and that occasional slice of decadent chocolate cake. Jon Frank is based in southern Minnesota. For more information, visit growyourownnutrition.com.
Reams Principles: Feed the Soil, Feed the Plant, Feed the Leaf BY JON FRANK During my first year making fertility recommendations for gardens, I made a wrong assumption. I had witnessed the steady fertility gains made in row crops with relatively modest fertility inputs. I copied what was working in row crops to the newly developed garden program and was surprised to find a failure in the making. The level of reserve fertility was in significant decline – especially calcium and trace minerals. To compensate I had to dramatically increase the nutrients I recommended and that fixed the problem. Vegetables remove far more earth minerals that grains, pastures and fruit trees by a factor of 2-10 times. And this difference in crop removal has to be accounted for by increasing fertility inputs. As I learned the principles of Reams teaching, I began to make a connection. Everything he taught in the abstract with detailed theory ultimately led to specific actions and inputs. What started in the theoretical always ended up with practical application. After more time listening to Dr. Carey Reams’ audio courses it dawned on me that all these actions and inputs could be consigned to 3 basic ideas. • Feed the Soil • Feed the Plant • Feed the Leaf Feed the Soil is about optimizing soil toward an ideal pattern. Feed the Plant is about giving a helping hand to the microbe/plant root barter system. Feed the Leaf is about foliar nutrition to further enhance yield and deliver trace minerals. The greatest success in Reams Agriculture comes when all 3 “buckets” are used in a complete program. Without a doubt, the greatest quantity of inputs is needed to Feed the Soil. The other buckets take far less inputs. The rest of this article will discuss the inputs needed to Feed the Soil. But first let’s address the question of why. Why use inputs? Because the proper use of inputs, with the help of plants and microbes completely changes the pattern of the soil. Imagine a chef commissioned to make the world’s best chocolate cake in less than 4 hours. What is he going to do? First, he is going to find the very best chocolate cake recipe, then he his going to assemble the finest ingredients, and lastly, he is going to follow the recipe meticulously. The highest quality cake is made with very specific levels of ingredients in very tight ratio with each other. Anything added too much or little or out of balance with other ingredients can completely ruin the cake. Just triple the salt and baking soda and the cake is not fit to eat. The same with soil. Instead of calling it a recipe we call it a pattern. The pattern of soil is determined by the levels and ratios of available minerals. If we want a better output of high-quality crops or nutrient dense foods then we must create the proper pattern in soil. You can’t get a prize-winning cake with a lousy recipe and neither can you achieve nutrient dense produce with deficient or imbalanced soil. You have to meet natures requirements if you want top quality. Let’s illustrate this with a typical soil test followed up by a decode of the soil pattern. All nutrients are in lbs. per acre on the Morgan soil Test. Nutrient Lab Result Desired Level Phosphorous 16 175 Potassium 290 175 Calcium 900 3,150 Magnesium 125 450 Ratio Result Desired Ratio Phosphorous to Potassium .05:1 1:1 Calcium to Magnesium 7.2:1 7:1 Calcium to Phosphorous 196:1 15-18:1 Calcium to Potassium 3:1 15-18:1 To calculate the ratio, take the lab result for the first nutrient and divide it by the lab result of the second nutrient. To calculate the Calcium to Magnesium ratio, divide 900 by 125 to get 7.2. This soil has a Ca:Ma ratio of 7.2:1. This general pattern is found all over the south and the eastern 1/3 of the United States. But in many instances the soils have even less fertility than this example. So, what does this pattern tell us? Here is the decode. • 16 lbs. of available Phosphorous indicates low brix and poor energy production in the plant. The energy cycle in plants depends on phosphorous since it is the P in ATP. • 290 lbs. of Potassium signifies there will be a crop. • Calcium at 900 lbs. means low yield, very poor root development, and inadequate feeding of soil microbes. Inputs to help the microbes are needed. • Magnesium at 125 lbs. is a sufficient amount for leaf function but still low. • The P:K ratio of .05:1 indicates broadleaf weed pressure. • The Ca:Ma ratio of 7.2:1 indicates a soil that is workable and not sticky. • The extreme Ca:P ratio of 196:1 further highlights how critically low phosphorous is and suggests insect and disease susceptibility. If Copper is also low and the year is wet, you might see a fungal attack. • The Ca:K ratio of 3:1 is the other extreme. Such a high level of potassium relative to calcium indicates poor cellular integrity of the crop. This happens when Potassium substitutes for Calcium in the cell walls. Altogether this is the pattern of a depleted soil. This soil can not produce high brix or nutrient dense food or crops in the near future. Animals eating forages grown on this soil will not perform well. The good news is this soil is easy to fix. The bad news is it is not cheap. Inputs to grow the upcoming crop and improve the overall soil pattern could include the following: • Soft Rock Phosphate • Low-Magnesium Limestone • 11-52-0 Mono Ammonium Phosphate • Calcium Nitrate • Epsom Salt What is not suggested for this year is an application of compost or manure. They should be avoided because potassium will increase and it is already too high. By giving a complete feeding to the soil it will impact roots and microbes. As the pattern changes to toward ideal crop health and yield improves. And so, does the nourishment of people and animals. Next month we will cover the inputs to Feed the Plant and Feed the Leaf. In the meantime, I hope you are enjoying a diet of nutrient dense foods and that occasional slice of decadent chocolate cake. Jon Frank is the owner of International Ag Labs (aglabs.com), based in southern Minnesota. He is a soil consultant with more than 20 years of experience in his field. He is the founder of High Brix Gardens (highbrixgardens.com), the market garden/backyard garden division of IAL. Jon is fascinated with the correlation between minerally rich soil and nutrient-dense food and its subsequent impact on human health.
Rancher Puts Allan Savory Principles into Action By Tracy FrischThis article also appears in the 2019 September issue of Acres U.S.A. Gene Goven is a dryland farmer in the center of North Dakota. He has owned and managed 1,500 acres of shortgrass prairie and cropland for the past 51 years. In 1986, the ideas of Allan Savory changed his life. When I reached out to him about visiting, he informed me of his deceptively simple mission: “To manage diversity for soil health enhancement.” Toward that end, he promotes biodiversity at every level and aims to capture rainwater and to deepen roots. As we will see, he has succeeded by a variety of measures. For Goven, the quest for a better way to farm has been a journey toward greater understanding. Learning occurs in steps rather than as a continual uphill climb. “All of a sudden another light comes on,” he said. “No one big thing made the difference,” he said of the evolution of his farm “It was many different little things. Nothing stands alone. If you change one thing, you change everything.” Bringing along fellow farmers and other people that interface with land management has been an important complement to Goven’s own learning. He has made presentations in 22 states and 3 foreign countries, and he continues to take pleasure in the positive changes he has witnessed among farmers in his immediate neighborhood and far beyond. People have to be shaken up a bit in order to rethink their belief system, he’s learned. “If the edges of someone’s paradigm aren’t ruffled, why would anyone want to change?” he asked. “Eighty percent of people are followers. Twenty percent are adapters. Less than a half of one percent are innovators.” Goven falls into the latter category. He just thinks differently about creating agricultural systems. And he isn’t the only one. Goven observed that more than half of the mentors in the North Dakota Grazing Lands Coalition are left-handed. He also has dyslexia. For many years, he considered it a disability, but over time he has come to see it as a gift. “There’s a little contrarian in me,” he said. Gene Goven holds western wheatgrass, grazed and ungrazed. Western wheatgrass is another important native cool-season rhizomatous grass. SHIFTING THE PARADIGM Goven credits his decision to cross-fence his paddocks with putting him on his lifelong path. He installed his first cross-fencing in 1980. Within a few years of starting to cross-fence his land, he had increased the stocking rate by 20 percent. And that was just the beginning. Subdividing his rangeland allowed him to more intensively manage cattle grazing, which boosted forage production. But cross-fencing wasn’t enough of a change to resolve his grazing issues. “I still couldn’t get the animals to eat uniformly,” he said. He continued to look for solutions. Goven found what he was looking for in November 1986 when he took his first Holistic Management class. Taught by founder Allan Savory, the course cost $1,500 and took Goven away from the ranch for five-and-a-half days. He questioned whether it would be worth it. “But I never looked back. I started thinking and not just acting,” he said. The biggest revelation came from Savory’s Holistic Planned Grazing concept, through which Goven was able to steadily increase forage production on native prairie. It taught him the importance of giving land an adequate rest following grazing. He began to understand that “we need to feed the soil first” and that livestock come second. Before 1980, with set stocking and no cross-fencing, an acre of Goven’s native prairie would only produce 450 pounds of dry matter in a good year. Now, even in a drought year, Goven says he counts on each acre yielding 2,000 pounds. For years now, Goven has managed his cattle so that they only harvest a fraction of his increased forage production. “I used to be puzzled by the concept of take half, leave half in rangeland management. Then it dawned on me that the severity of leaf removal means the plant has to start again,” Goven explained. If cattle are left in a paddock for too much time, they will munch on the regrowth of plants that they’ve already taken bites from. “I’ve kept livestock in a paddock too long. I’ve thought there’s enough forage for another day,” he said. That mistake can devastate a paddock for the next two or three years. Goven considers weather (moisture and temperature) and the rate of plant growth, as well as the quantity of standing forage, when determining how frequently to move the cattle. When plants are lush and growing fast, he doesn’t let the cattle stay in a given paddock for more than three consecutive days. But in dry weather, when plants are barely growing, he may leave cattle in the same paddock for 7 to 10 days, or even 14 days, depending upon the paddock size. Gene Goven monitors soil health. Although he’s semi-retired, Goven still never stops learning new things about his land in North Dakota. ‘MANAGING FOR CHAOS’ Goven cautions graziers to be conservative when grazing forages in the fall, after they green up following summer brown. Taking off too much grass can effect the next year’s production by as much as 50 percent, he warns. Around a decade ago, Goven added an interesting twist to his planned-grazing sequence. He fittingly named it “managing for chaos.” Every year he changes the approximate date of grazing in each paddock. If he grazed a particular paddock around June 1 one year, he won’t graze it again in early June for another 10 years. This approach has enriched the species diversity of his native prairie. While 50 or 60 percent of the local farmers have native prairie on their ranches, continuous grazing and other non-optimal practices simplify the species composition of these grasslands. CARRYING MORE CATTLE Changes in his grazing management have boosted the carrying capacity of Goven’s land. “Prior to 1980, we’d be able to run 55 to 60 cow-calf pairs on a good year,” he said. Back then a drought would force him to drastically reduce the herd to 35 or 40 cow-calf pairs or “there’d be nothing to eat.” In the 1980s, after he started putting up cross-fencing, he increased his herd size to 72 cow-calf pairs. By 2000 he was up to about 105 pairs. These days he often grazes 150 to 180 pairs, though it varies by year. Besides native prairie and hay, Goven’s farm provided other sources of feed for the herd. After cash crops were harvested, his cattle would graze the crop aftermath. Cover crops also provided forage for later grazing. TWIN PROBLEMS On rangeland, two opposite management scenarios produce equally negative outcomes. A study by the Agricultural Research Service at Mandan, North Dakota, found that under continuous grazing and in the absence of grazing, native prairie grasses have very shallow roots — just 3 to 5 inches in depth. Under a planned rotational grazing regime, the roots of these grasses extended 6 to 10 times deeper and were much fuller, with obvious implications for withstanding drought. This research supports the notion that idle rest brings harmful consequences. The Conservation Reserve Program rested land for 20 years. However when standing grass or grain stubble is left alone over the winter, it loses up to 20 percent of its weight through oxidation. The quality of standing vegetation and the health of the soil reach their peaks within five to eight years, before declining, Goven said. SOIL HEALTH Grazing converts forage into something that’s more readily marketed in the form of livestock. For Goven, the value of cattle also lies in its ability to enhance soil health. Grazing animals fertilize grasslands with urine and manure and feed the soil-food web. Animal hooves also can produce a positive impact on soil. Animal impact, when managed appropriately, causes carbon to be slowly released into the soil. Trampling vegetation puts plant residues in contact with the soil, where the soil-food web can break them down and recycle them. “Soil microbes have a very low browse line,” Goven explained. RETIREMENT PLAN More than 20 years ago, Goven stopped keeping cattle as property. Instead he custom-grazes other people’s bovines. He likes using someone else’s equity to market forage. Like other custom graziers, he charges by the head per day, adjusted by the size and type of animal. Taking in disparate groups of animals managed under different regimes can present serious handling challenges. That hasn’t been a problem for Goven. Rather than herding or chasing the cattle, he trains them to follow him. In his slow process of retiring, Goven has been gradually cutting back on his farming obligations. He currently rents cropland to two brothers. In the lease, he put in some stipulations about stewardship. He cautioned the farmers not to use any fungicides because of their impact on microorganisms in the soil-food web, like mycorrhizal fungi. They use herbicides at a drastically reduced rate — in line with Goven’s practice — and they hire Goven to plant cover crops on his own land. BUILDING THE SPONGE A Natural Resources Conservation Service study site in South Dakota compared soil properties of pasture under two management regimes: continuous, season-long grazing versus rotational grazing. With rotational grazing, the top 12 inches of soil gained an additional 1 percent organic matter. One percent of soil organic matter equates to about 20,000 pounds per acre. The soil in the rotationally grazed pasture infiltrated water almost 10 times faster than continuously grazed pasture. It took 12 minutes for an inch to infiltrate under the rotational grazing treatment instead of 109 minutes on the continuously grazed land. Goven’s farm also reveals this contrast, though in time rather than space. Decades ago, monitoring by agencies such as NRCS (then known as the Soil Conservation Service), North Dakota State University Extension and the Agricultural Research Service showed that his farm infiltrated water slowly, at the rate of around 0.8 to 1.2 inches per hour. Over time, as a result of dramatic changes in grazing and cropping practices, water infiltration improved greatly. “Now my poorest rate is 6.5 inches per hour. The best is 12 inches per hour,” he said. He referred to the example offered by his late friend Neil Denis of Saskatchewan, who converted his cropland to perennial forages. “The mob grazier king of the world” was also an early adopter of Holistic Management. His soils infiltrated at the rate of 15 inches an hour, while his neighbor’s cropland clocked in at a mere half inch per hour. COVER CROPPING Goven grew up with his family growing cover crops and doing companion planting. “In the middle 1930s my grandfather, Ed Goven, was paid to plant sweet clover in with his grain crops,” he said. One year of his crop rotation had to include clover as a companion crop. But then overproduction emerged as a problem that threatened to destabilize the economy. The federal government responded by penalizing practices such as cover cropping. Farmers were directed to leave a certain amount of acreage fallow. By taking land out of production, the government hoped to prop up farm gate prices. After World War II, agrochemicals came along, further pushing cover crops and intercropping out of favor. Goven remembers his dad and granddad using cereal rye “to clean up the fields,” making use of its allelopathic properties. They would harvest some of this rye for hay and turn under other fields of rye. MULTI-CULTURAL Long ago Goven started experimenting with bi-cultures and polycultures on his own farm. For example, he might interseed lentils with a cash crop of sunflowers. Planted at the rate of 10 to 12 pounds per acre, the lentils serve as “the fertility program” for the sunflowers. Field peas play that same role with oats. And instead of broadcasting commercial fertilizer, Goven became accustomed to interseeding lentils and turnips into winter wheat at spring green up. Dr. Jill Clapperton of Hamilton, Montana, has studied the synergy between legumes and grasses and how it affects plant behavior. Legumes will share up to 70 percent of the nitrogen they fix with a grass-type crop. When lentils and/or field peas were planted together with a grass, they nodulated within 5 days of emergence. At just an inch tall, lentils already had pink nodules on their root to fix nitrogen. In monoculture plantings, it took up to 30 days for lentils to nodulate. Grown with ample nitrogen fertilizer or in the absence of a hungry grain crop, the legume has no need to fix nitrogen. “The legume is lazy” is how Goven put it. Researchers at North Dakota State University and the Agricultural Research Service looked at the rooting depth of oats and inoculated field peas grown together and separately. They found that in intercropped plantings they rooted four times deeper than either species did when grown alone. That’s more good evidence for growing legumes and grains in combination. INFLUENCING FARMERS Influencing fellow farmers to improve the environment has long been central to Goven’s mission. He quotes Allan Savory’s instructions to him: “Work with your neighbors. Don’t antagonize them.” Goven has taken this counsel to heart. He wants to help guide his immediate community and takes great pains not to insult or alienate any of his neighbors. Several times during our conversations, he reminded me, “You won’t catch me doing boundary line comparisons!” His efforts have borne fruit. Most of his neighbors who work smaller farms practice no-till and use cover crops. Goven has been instrumental in bringing about this shift. Goven encourages fellow farmers to not let the cost of seed get in the way of adopting cover crops. He tells them to start with whatever is at hand. “What do you have left over in your grain bin – corn, oats, sunflowers?” he asks. He recommends buying individual species separately and making your own cover crop seed mixes. He also custom-seeds cover crops for other farmers. They contract with him to plant no-till cover crops following the combine. “I’ve even had requests to seed cover crops from 50 and 70 miles away,” he said. He also has made it easier for his neighbors to adopt no-till practices. “I’m willing to lend out my no-till drill to neighbors. I lent it to one neighbor. A year ago they bought their own,” he said. REACHING NON-FARMERS Goven is pleased to have been able to influence people outside of agriculture that are in a position to support better approaches to farming. Kent Linney first visited Goven’s farm as a high school student. He later became a plumber and a leader in Ducks Unlimited. Today he promotes livestock as a component of the organization’s program for habitat enhancement. “Seeing my farm must have really impressed him,” Goven quipped. He went on to list other individuals who have come to recognize the value of regenerative agriculture for its ecosystem and public health benefits. A North Dakota big game biologist told him, “Because of you, I have the career I have, using livestock as a habitat management tool for wildlife enhancement.” And Greg Sandness, the state’s water-quality specialist in Bismarck, told Goven, “If everyone was doing what these guys are doing, I wouldn’t have a job!” That’s because farms like Goven’s so dramatically reduce runoff and leaching. TRICKLE DOWN Goven rejects the notion that water quality starts at the edge of a lake or stream. He holds a more expansive view of what it takes to protect water resources. “For me, riparian management starts at the top of the hill and extends over to the next hill,” he said. As he sees it, protecting water quality must address water infiltration, through-flow and re-flow. Goven’s views are relevant because his farm is bisected by Crooked Lake, a beautiful water body that is used for recreation. The farm contains almost four miles of shoreline. Some years ago, the presence of Goven’s cattle near the lakeshore sparked complaints from several “cabin people” on the lake. An extension water-quality specialist stopped by to investigate. When Goven took her around, she could not find any visible evidence of erosion. That evening, she called her husband and told him to start cross-fencing. PRAIRIE POTHOLES Goven composed a bold goal for rain on his land: “Every raindrop shall infiltrate where it falls, no matter steep the hill is.” After he intensified his grazing management, he noticed welcome changes in the behavior of water on his farm. Water infiltration kept improving, resulting in less risk of run-off, erosion, flooding and drought. The ranch sits in the middle of the Prairie Pothole region, the waterfowl nesting and breeding capital of North America. The region stretches northwest from Iowa through large portions of the Dakotas and into three Canadian provinces. Three decades ago, Goven began noticing an odd phenomenon. His potholes would stay empty while his neighbors’ potholes were brimming full of water. This confounded him. A breakthrough in understanding came in 1990. Following two years of drought, four inches of rain fell in less than an hour on the evening of July 3. There was immediate flash flooding, and fences were torn out. But not on Goven’s farm. “All the slews and potholes filled with water on my neighbors’ land. I didn’t have any standing water and my potholes stayed empty,” he recalled. Seven days later, water started showing up in the ranch’s potholes and wetlands. Goven had captured every raindrop. “My wetlands and potholes hold water longer and better than they used to, but they also don’t fill up as much,” Goven said. This periodic drying up of prairie potholes is beneficial. When potholes constantly hold water, they go anaerobic. As a result they smell like a sewer. But if their water levels go up and down, when they do dry up, they re-vegetate. And when it next rains and the potholes take up water, that vegetation provides food for invertebrates and they in turn feed migratory waterfowl. WILDLIFE REFUGES Goven is proud of his work in helping U.S. Fish & Wildlife Service’s recognize the use of livestock as a management tool for achieving its mission of habitat enhancement. The agency’s wildlife refuges in North Dakota aim to provide habitat for migratory waterfowl. During the serious drought years of the mid and late 1980s Goven was looking for a way to avoid having to liquidate his cattle herd for lack of sufficient forage. He came up with the idea of grazing wildlife refuges, one of which is only 15 miles from his ranch. When he and a neighbor rancher went looking for duck nests on that refuge, they couldn’t find any. “Initially the only place we found nests was outside the refuge,” he said. Goven proposed using cattle grazing as a land management tool to improve habitat on the refuge. The agency’s regional director flew to North Dakota from Denver and gave him the go-ahead to “prove” that his idea would work. Goven and his neighbor did the pilot project, sharing labor and resources. They ran their cattle together in the refuge using temporary electric fencing powered by battery-operated fence chargers. Using livestock brought refuge lands back to health by enhancing nutrient cycling, energy cycling and water cycling, Goven said. “In three years we turned it from a biological desert into a preferred nesting area,” he reported. As a result of this success, “all refuge managers in North Dakota were required to attend sessions with me on prescribed grazing in the WPA Waterfowl Production Area,” he said. As a cooperator with U.S. Fish & Wildlife, Goven received the extra grazing land he needed, thus solving his feed problem. A national outcry (“Cattle-Free by 1993”) calling for the removal of all livestock from public lands had no effect on Fish & Wildlife practice in the U.S., as the benefits of the grazing program were so well-established. The program has had one big limiting factor however; U.S. Fish & Wildlife Service can’t find enough cooperators willing to bring livestock in. CATTLE WITHOUT CHEMICALS For 25 years, Goven hasn’t used pesticides of any kind to control insects and parasites on his cattle or pasturelands, including insecticidal ear tags. He doesn’t worm his cattle or use products like Ivermectin. He stopped using these biocides to avoid collateral damage to non-target species. If he were to turn to insecticides, he estimated that 80 beneficial insect species would be destroyed for every cattle pest insect he killed. He strives for rapid nutrient cycling on his farm, and giving up these biocides is consistent with this aim. At the Goven ranch, dung beetles, other insects and earthworms begin colonizing and breaking down cow patties within three days. In the absence of these small manure-loving animals, fresh cow paddies become dried up cow “Frisbees.” Nutrients remain tied up in them for months or years. Nitrogen in this desiccated manure is readily lost through volatization into the atmosphere, however. “For fly control, I’ll skip a paddock so there’s a quarter mile gap,” he said. This “leapfrog” approach creates a big enough distance between cow patties to limit fly populations. Similarly, moving cattle frequently to new paddocks can be an effective means of interrupting the life cycle of internal parasites. Cattle excrete internal parasite eggs in their manure. Newly hatched larvae climb up stems, waiting to be ingested by a host animal. Young calves are most vulnerable to the effects of parasites. The key to managing these parasites with grazing involves not returning animals to a paddock when the worms are in their infective stage. New Zealand data show that graziers can attain up to 90 percent parasite control with planned rotational grazing, Goven said. GETTING THE DRIFT If you’re trying to enhance biodiversity, pesticides of any kind can pose a threat. Over the course of his farming career, Goven said, “I got more and more disturbed by the increasing use of chemicals. It seemed like the landscape was going dead.” He’s been particularly dismayed by the use of herbicides, most commonly glyphosate off-label, as desiccants to dry-down crops shortly before harvest. Sixteen years ago, Goven’s ranch experienced herbicide spray drift damage. An aerial applicator, hired to kill weeds in a wheat crop on neighboring croplands, neglected to shut off his booms while circling out beyond to go back to the field he was spraying. The spray mixture contained Roundup and other herbicides used off-label. “I’m still suffering from chemical residual,” he said. A TRUE ECOSYSTEM Some ranchers attempt to improve the productivity of native prairie rangelands by no-tilling in purchased forage seed. Goven has never seen a need for such intervention. Rather, he works to retain and enhance the diversity of prairie species. “For every grass-type species, I want to have at least five forb species because they have deeper rooting systems, some down to 15 feet deep,” he said. Goven has identified some 200 different native plants growing in his shortgrass prairie. Years ago, he created a slide show of these plants and their historic uses. He especially enjoyed taking this program to senior citizens, including Alzheimer’s groups, because many elderly people would come alive seeing the plants of their childhoods. One June around 25 years ago, the National Audubon Fish and Wildlife Refuge held part of its annual field day on Goven’s ranch. That day, when bird watchers did a noon bird count on a quarter mile stretch at the ranch, they counted an astonishing 112 different bird species in one hour. The varied habitats on that site included brushy ground, lakeshore and prairie potholes. “I was told that there are very few places in the world with that concentration of species,” Goven said.
Soil Fertility: 16 Methods to Understand By Hugh Lovel Soil fertility and sustainable agriculture practitioners know that most soils today need their health and vitality rebuilt. In times past, nature built healthy, vital soils, and there is value in copying nature in rebuilding soil health. However, we cannot afford to take millions of years to do so as nature did — we need intelligent intervention. Cultivation, grazing, composting, soil conservation, green manuring, soil testing, soil remineralization, fertilizer priorities, fossil humates, and visual soil assessment all play a role in establishing self-regenerative, self-sufficient, fertile soils. The biological activities at the basis of self-regenerative soil fertility occur at the surfaces of soil particles where minerals come into contact with water, air, and warmth. It is at these surfaces that biological activities provide nitrogen fixation and silicon release. In nature, soil organisms cultivate the soil. Building Soil Fertility Nature, with minimal human intervention, developed biologically diverse, richly fertile soils and ecosystems with little by way of inputs other than the accumulation of dust, periodic rainfall, fresh air, and sunlight. Rainforests are fertile ecosystems with rich diversity of microbial, plant, and animal species. While rainforests can be quite fertile, the world’s deepest, richest topsoils evolved as grazing lands — prairies, steppes, plains, savannahs, veldt, and meadows that grew grasses, legumes, and herbaceous plants and supported herds of herbivores along with the predators they attracted. Andre Leu, Soil Carbon, from the 2007 Eco-Ag Conference & Trade Show. (53 minutes, 44 seconds). Listen in as Leu, the director of Regeneration International, teaches how to store and repurpose carbon in your soil. In both forests and grasslands, vegetation draws in carbon. Forests store most of their carbon above the surface of the soil where it cools the earth and helps precipitate rain. Grasslands store more of their carbon in the soil as humus complexes. Forest fires return most of the carbon to the atmosphere, but with grassland fires most of the carbon remains in the soil. Nature’s way of building soil fertility involves awesome diversity and intense cooperation. Every ecological niche is filled, every need is satisfied, and everything is gathered, recycled, and conserved. No area is left bare, and no opportunity lost. And nature is patient. If something is missing or deficient it may take eons upon eons for it to accumulate from dust and rainfall or cosmic ray bombardment. Nature can also use our help. Cultivation In nature, soil organisms cultivate the soil — from the smallest protozoa, arthropods, nematodes, mites, and collembolans to beetle grubs, earthworms, ants, and even larger burrowing animals. Plants and their fungal symbiotes spread rocks and soil particles apart by growing into pores, cracks, and crevasses. They secrete substances that etch the surfaces of rocks and soil particles and feed micro-organisms that free up minerals. Inevitably, at some point, animals will consume the plant roots and open up passages where air and water are absorbed by the soil. Some, like earthworms, grind soil particles up in their digestion processes. They also recycle plant matter as manures, building soil fertility and feeding further growth. This softens the soil and builds crumb structure, tilth, and retention of moisture and nutrients, while allowing water, air, and root penetration. Conversely, continuous grazing — to say nothing of human and machinery impact — compresses the soil and reverses these gains. Earthworm in soil. Mechanical cultivation softens the soil and prepares a clean seedbed for planting. For the most part, cultivation destroys soil life and is highly digestive and oxidative. In an age of machinery and power equipment with excessive cultivation and monocropping as the norm, this provides more and faster nutrient release as it collapses the soil biology. More importantly, it depletes nutrient reserves. This leads to higher and higher fertilizer inputs while biodiversity and soil fertility decline. Even back in the 1920s, Rudolf Steiner saw these trends and introduced horn manure [500], horn silica [501], horn clay, and biodynamic compost made with the herbal preparations [502-507] as remedies. But we also need to reverse the trends outlined above. Too much cultivation burns up organic matter, impoverishes soil life, breaks down soil structure, and releases nutrients that then may be lost. Wind and water erosion may also occur, and the result all too often is loss of soil fertility. The biodynamic preparations are no universal remedy for all mistakes. We must farm sensitively and intelligently as well. Author and Agronomist Neal Kinsey, Prioritizing Fertilizer Needs, from the 2008 Eco-Ag Conference & Trade Show. (1 hour, 17 minutes.) Listen in and Neal teaches a classroom about how to quantify your fertilizer needs and make a plan for your growing operation. Various strategies are used for minimizing cultivation damage while still enjoying cultivation’s benefits. Some crops, such as potatoes, require cultivation. But with a mixed operation, crop rotations can take this into account and soil building can still proceed. Strip cropping, composting, and rotations in pasture and hay can help restore diversity so that soil biology recovers. Controlled traffic, where machinery strictly follows predetermined lanes, reduces compaction. No-till and minimum-till planting methods help, especially when used with biological fertilizers and biodynamic preparations to feed the soil food web and take the place of harsh chemicals. Inter-cropping, multi-cropping, and succession cropping increase diversity and reduce machinery impact. Instead of herbicides, managing mixed vegetative cover on roads, access strips, headlands, fence rows, laneways, waterways, and ditches provides biological reservoirs that interact with cultivated areas. Grazing High-density cell grazing is particularly effective. In this technique, large numbers of livestock graze and trample small blocks for a few hours and then are moved on, not to return until plants have regrown. Based on what a pasture needs rather than on a calendar, this could be two weeks, two months, or more than a year. Sarah Flack, Integrating Livestock into the Farm, from the 2006 Eo-Ag Conference & Trade Show. (1 hour, 32 minutes.) Listen to Sarah’s instructional workshop, as she teaches specific tactics for integrating livestock into your soil management program. With high-density cell grazing the impact is minimal, and what is not grazed is trampled so the more sought-after plants that get grazed hard have a chance at regrowth. Soil animals recycle what is trampled, feeding it back to the regrowth. Composting Composting is more than a simple process of digestion and decay. Nature breaks down every sort of organic material into simple carbohydrates and amino acids, but in many cases these would oxidize and leach if there weren’t ways of storing and conserving them in easy-to-use forms. Bees gather nectar, digest it, concentrate it, and store it in their honeycomb. Similarly, there are microorganisms in the soil that gather up loose nutrients, store them in large, carbon molecules called humic acids and complex them with clay particles in the soil. As with bees, the organisms that gather and complex these nutrients have access to them when needed, and these microorganisms are mainly the actinomycetes and mycorrhizal fungi that form close relationships with plants to the benefit of both. To favor these microbes and their activities, manures and organic wastes can be composted by building stacks, piles, or windrows with a favorable mix of carbon and nitrogen rich materials, soil, moisture, and air. A ratio of 30 to 1 carbon to nitrogen materials along with 10 percent soil and at least 50 percent water is a good starting mix. Edwin Blosser: Composting Made Simple, from the 2017 Eco-Ag Conference & Trade Show. (1 hour, 58 minutes) Listen in as Blosser, the founder of Midwest Bio Systems, explains how to make compost, and how it can be used on a commercial scale. Into the newly built pile, insert a small spoonful of each of the herbal “composting” preparations described in Steiner’s agriculture course. In the case of the valerian flower juice tincture, the liquid is diluted in water, stirred intensively, and sprinkled over the pile. Sprinkling the horsetail herb over the pile before covering can also help. These preparations impart a balanced range of activities that assist and improve the breakdown and humification process. A covering of some sort will be very helpful in providing an outer skin or membrane that holds in the life and vitality of the compost heap as it matures. Once it is stable with most of its nutrients bound up in humic complexes, its microbial activity should be rich with nitrogen-fixing, phosphorus-solubilizing, and humus-forming species. Using the composting preparations is equally important in large-scale composting operations, whether piles are frequently turned or left static. Biochemical Sequence of Nutrition in Plants Plant biochemical sequences begin with: 1. Boron, which activates 2. Silicon, which carries all other nutrients starting with 3. Calcium, which binds 4. Nitrogen to form amino acids, DNA, and cell division. Amino acids form proteins such as chlorophyll and tag trace elements, especially 5. Magnesium, which transfers energy via 6. Phosphorus to 7. Carbon to form sugars, which go where 8. Potassium carries them. This is the basis of plant growth. Soil expert and author William McKibben, The Art of Balancing Soil Nutrients, from the 2009 Eco-Ag Conference & Trade Show. (1 hour, 8 minutes). Listen in as McKibben talks about the steps you can take after you receive your soil test results to help balance your soil. However, consider the economies of scale. On the one hand, Steiner indicated that each preparation need only be inserted in a single place — even in a pile as large as a house — and its effects would radiate throughout the pile. On the other, since Steiner’s death special composts known as manure concentrate, Cow Pat Pit (CPP), and barrel compost contain all the herbal preparations in one easy-to-use formula that can be stirred intensively for 20 minutes and sprayed throughout the pile as it is assembled or added to the water used to moisten the compost. This can bring the benefits of the preparations into a large-scale operation economically. Some composters prefer to use the horn preparations with the herbal preparations, and a biodynamic agriculture Australia formula called Soil Activator combines all the preparations in one compound that is stirred and applied like CPP. According to John Priestley, one of Australia’s most experienced and innovative biodynamic farmers, “the only way the biodynamic preparations don’t work is if you don’t use them.” Volatilization & Leaching A criticism identified by organic farm research is volatilization and leaching from raw animal or plant wastes. These losses can be pollutants in the atmosphere, in waterways, or in the water table. Biodynamic management of plant and animal wastes prior to application on soils involves composting of solid wastes and fermentation of liquids, such as effluents, with the herbal preparations. All materials need to be broken down into stable humus or stable liquid brews before use. Proper application of the full range of biodynamic preparations ties up loose nutrients and minimizes run-off or leaching. Rank manure smells are a sure sign of nitrogen loss and are also an invitation for weeds, pests, and diseases. This is neither a plus for soil fertility nor a plus for the environment. Wherever animal wastes collect or nitrogenous materials break down, soil or rock powders can be scattered and CPP or Soil Activator sprayed to minimize losses and keep smells in check. Cover Crops & Green Manures In general, cover crops and green manures are quick-growing annual plantings of grasses, legumes, and herbaceous species intended to rebuild soil biology, restore nitrogen fixation, and provide material for grazing, composting, mulching, or ploughing back into the soil. In some cases seed is harvested off of these mixes before they are grazed, composted, used for mulch, or ploughed down. Applications of barrel compost, CPP, or Soil Activator can assist in rapid breakdown, re-incorporation, and humification of these green manures. Clover Field Ideally, cover crop mixtures should include at least 15 to 20 species of annual grasses, legumes and herbs. These can restore diversity; rebuild soil biota; conserve loose nutrients; help with pest, weed and disease control; increase soil carbon; conserve moisture; reduce run-off; and prevent erosion — while protecting what might otherwise be bare soil. South Dakota farmer Gabe Brown, author of Dirt to Soil, speaks in 2016 at the Eco-Ag Conference and Trade Show. (1 hour, 18 minutes.) Listen in as Gabe Brown talks about how he uses cover crops to build soil health. Broad-acre cover crops may be under-sown with succession species to take over after harvest. Or cover crops may be planted as catch crops at the end of growing seasons. They may also follow short season crops depending on region and climate, and they can provide handy ways to feed rock powders and composts to the soil biology. Vegetation is almost always a plus, while bare soil ensures the opportunity is lost. For example, a winter crop of oats, lupines, rape, clovers, and corn salad could be taken to the point the grain and other seeds are harvested and separated. Alternatively, mixes of winter cereals, legumes, and broadleaf plants might include wheat, barley, rye, triticale, vetches, clovers, medics, turnips, mustards, rape, and radishes. If the area in question is to be used as pasture, perennial grasses, legumes, and other species such as dandelions, plantains, chicories and yarrow may be sown along with the annuals as succession species. For summer covers, a mix may include different kinds of sorghums, millets, cowpeas, lablab, maize, soybeans, and buckwheat, harvested either green or at seed to be milled for animal feed. Experiments along these lines were pioneered by Colin Seis of Winona Farms in Australia. Direct seeding (minimum or no-till) of a diversified mixture of compatible annual species into existing vegetation, such as pastures and hayfields, shows considerable promise for soil improvement and increased forage yields, and at the same time reduces risks where droughts can be followed by floods that would devastate cultivated soils. Soil Testing Before bringing in manures or mineral inputs it is important to have reliable information about what is already there. Soil testing can be helpful, but it also can be misleading. Since the birth of chemical agriculture, most soils have been tested for soluble nutrients using dilute solutions of mild acids in an attempt to mimic the weak acids plants give off at plant roots. This ignores the wider range of soil biology and assumes plants only access those elements in the soluble form as shown by the testing method. Neal Kinsey, Using Soil Analysis to Grow Crops, from the 2005 Eco-Ag Conference & Trade Show. (50 minutes, 12 seconds). Listen in as agronomist Neal Kinsey, the author of Hands-On Agronomy, teaches about how to test your soils, and use that data, to increase crop yield and decrease weed pressures. In his retirement, Justus von Liebig, the father of chemical agriculture, realized he was wrong in thinking plants depended on solubility. Rudolf Steiner took up the challenge of correcting Liebig’s errors in his agriculture course. Time passed, and Ehrenfried Pfeiffer, who worked closely with Steiner in his agricultural research, immigrated to the United States after World War II and set up testing laboratories in Spring Valley, New York. He conducted extensive total testing of soils and found that most soils contained large quantities of nitrogen, phosphorus, and potassium that didn’t show up on soluble tests. These were the very elements being applied in large quantities to agricultural crops, though soils continued to decline in fertility. In many cases, soil biology, given encouragement and sufficient trace elements, would provide access to the insoluble but available nutrients stored in the humic fraction of the soil. However, fertilizer industries using soluble testing as a sales tool and selling farmers minerals they already had in abundance were unstoppable. They perpetuated Liebig’s errors and financed ongoing research into solubility-based agriculture, building a momentum that relegated Liebig’s final wish to obscurity. Today in Australia, Environmental Analysis Laboratories at Southern Cross University in Lismore, New South Wales offers both the soluble Albrecht test and a hot aqua regia total digest test similar to the one Pfeiffer used. EAL accepts samples from anywhere in Australia or the world. The Albrecht test measures the ratios of calcium, magnesium, potassium, and sodium, which are the major cations or metallic elements in the exchangeable portion of the soil. The ratio of calcium to magnesium is particularly important for soil mechanics. Heavy soils may need as high as a 7-to-1 ratio of calcium to magnesium to crumble and expose particle surfaces. By the same token, light soils may need more like a 2- or 3-to-1 ratio to hold together. Other soluble analysis targets of importance for robust, vigorous growth include 50 ppm sulfur, 2 ppm boron, 100 ppm silicon, 70 ppm phosphorus, 80 ppm manganese, 7 to 10 ppm zinc, 5 to 7 ppm copper, 1 ppm molybdenum, 2 ppm cobalt, and 0.8 ppm selenium. In total tests, the targets for nitrogen, phosphorus, and potassium depend on the carbon content of the soil, since most soil reserves are stored in humus or accessed by humus-based organisms. Most importantly, total testing addresses what is contained in the soil reserves despite what may seem like deficiencies in soluble tests. As Pfeifer discovered, it is common to find huge reserves of phosphorus, potassium, and other elements that are deficient in soluble tests, which indicates something else is going on. The Biochemical Sequence There is a hierarchy or biochemical sequence of what must function first before the next thing and the next thing works. The elements early in this sequence must be remedied before later elements have much effect. Nitrogen, phosphorus, and potassium occur late in this sequence, while sulfur, boron, silicon, and calcium start things off. Since everything going on in the biology of the soil occurs at the surfaces of soil particles where minerals combine with water, air, and warmth, sulfur is the essential key-in-the-ignition for activating the soil biochemistry. Neal Kinsey, Compost & Manure Analysis, from the 2005 Eco-Ag Conference & Trade Show. (50 minutes, 39 seconds.) Listen to Neal Kinsey’s helpful lecture on how to test compost and manure, to ensure those inputs are balancing your crops and soil. Sulfur works at the surfaces, boundaries, and edges of things to bring life and organization into being. It is the classic catalyst of carbon-based chemistry. Regardless of the other soluble elements in the soil test, there should be 50 ppm sulfur [Morgan test] for biological soil fertility to function properly and a 60 to 1 carbon to sulfur ratio in the total test. Silicon & Boron Silicon forms the basis for the capillary action that transports nutrients from the soil up. Fortunately for agriculture, the activity of silicon is to defy gravity, but this silica activity relies on boron, a component of clay, to do so. Boron is the accelerator while silicon is the highway. If either boron or silicon is deficient, the soil biology will function below its potential. Ironically, the most effective way to make sure boron and silicon are deficient is clean cultivation and heavy use of soluble nitrogen fertilizers. This is modern agriculture. Calcium Calcium, which comes next in the biochemical sequence, is the truck that travels on the highway. It collects and carries with it the nutrients that follow in the biochemical sequence. As the opposite polarity from the aloof silicon, calcium is hungry, even greedy. Calcium engages nitrogen to make amino acids (the basis of DNA) RNA, and proteins. These in turn are responsible for the complex enzyme and hormone chemistry of life that utilize magnesium, iron, and various trace elements as well as depending on chlorophyll and photosynthesis for energy. Photosynthesis is where magnesium, phosphorus, potassium, and a wide range of micronutrients follow nitrogen in the biochemical sequence. Unfortunately, NPK fertilizers stimulate this latter portion of the sequence without addressing the priorities of sulfur, boron, silicon, and calcium. The NPK approach usually grows crops that are highly susceptible to pests and diseases. Minerals & Rock Powders Even though biodynamics is primarily about organization and biological activities, soil mineralization must be considered. It is pretty hard to organize something if it isn’t there. Many soils need gypsum or elemental sulfur. Many soils also need boron, especially after nitrogen fertilization, but also following overgrazing or clean cultivation. Silicon may also be needed to get the soil biology up and running so it can release more silicon from the surfaces of soil particles. It too is depleted by overgrazing, clean cultivation, or nitrogen fertilization. Many ‘organic’ farms using raw manure — especially chicken manure — as a nitrogen source, which deplete their sulfur, boron, and silicon. In addition to silicon rock powders, lime provides calcium; dolomite provides magnesium; and rock phosphorus provides silicon, calcium, and phosphorus. There are also natural potassium sulphates, and many rock powders provide trace elements. For high pH soils with large excesses of sodium and potassium, the remedy may be humates and zeolite to buffer pH and build additional storage capacity. Gary Zimmer, Gaining a Working Knowledge of Calcium, from the 2002 Eco-Ag Conference & Trade Show. Listen to Gary Zimmer talk about how calcium drives the flow of other minerals and nutrients through the soil and plant, and how to measure and balance calcium levels in your fields. Most importantly, the biochemical sequence shows us we need to start with a full correction for sulfur to expose the surfaces of soil particles to biological activity before the biochemistry can kick in. Other methods may not recognize sulfur’s key importance, but in biodynamics this should be clear. Liebig’s ‘law of the minimum’ rightly says plants only perform as well as their most deficient nutrient. Calculating Inputs A soil test can show how many parts per million (ppm) of each element are present and whether target levels are being met. The question is, how can we calculate the right adjustment and add no more and no less? Fortunately there is a rule of thumb. Two-hundred and fifty kg/ha (250 lbs/ac) of any input supplies that input’s percent analysis as parts per million. Note: This is based on the average weight of the top 17 centimeters of soil in 1 hectare, which is approximately 2,500,000 kilograms (to calculate, 2,500,000/250=10,000 which is 1 percent of 1 million parts per million). Since a hectare is 2.5 acres and a kilo is 2.2 pounds we can approximate this rule fairly closely using 250 pounds per acre in the place of kilos and hectares. For example, if the soluble test for sulfur (Morgan test) shows 5 ppm when the target is 50 ppm, then 45 ppm sulfur is needed. If gypsum is 15 percent sulphur, then 750 kilograms per hectare (750 pounds per acre) gypsum will deliver 45 ppm sulfur. If gypsum is 20 percent S, then 565 kilograms per hectare (565 pounds per acre) will be required. If the gypsum is 12 percent S, then nearly a metric ton per hectare (or 1,000 pounds per acre) is needed. Since gypsum is calcium sulphate, it provides both calcium and sulfur, which is usually desirable. However, in the event that the soil is already rich in calcium and has a pH of 6.3 or higher, elemental sulfur may be a better choice. In contact with moist soil, sulfur will oxidize to sulphate and lower the pH slightly, but it will open up the surfaces in the soil, stimulate soil biology, and release some mineral reserves. For practical purposes, elemental sulfur may be combined with 10 percent bentonite for ease of handling. Ninety percent elemental sulfur would require 125 kilograms per hectare (125 pounds per acre) to deliver 45 ppm S. As a different example, sodium molybdate is 42 percent molybdenum. To add 0.5 ppm Mo to the soil requires 42 divided by 0.5, which equals 84. If we divide 250 kilograms by 84 we get 2.976 kilograms sodium molybdate. However, to add this much in one go would be expensive and unwise. With most inputs, especially the traces, the soil has trouble adjusting to a full correction of anything other than sulfur. In the case of sodium molybdate, 0.5 kilograms per hectare (0.5 pounds per acre) is the usual correction and 1 kilogram per hectare (1 pound per acre) is considered the limit. The maximum manganese or zinc sulphate per application per hectare is 25 kilograms per hectare (25 pounds per acre), and copper sulphate rarely is applied at any rate higher than 15 kilograms per hectare (15 pounds per acre). Boron, Humates, and Trace Minerals When adding trace elements, especially boron, feeding the fungi of the soil food web is essential. Fungi hold on to inputs that would otherwise leach. If available, well-humified compost produced on the farm is highly desirable. If this is not available, then other humic inputs must be considered. Humic acids are extracted commercially from carbon-rich deposits such as leonardite, soft brown coal, and peat. While raw leonardite or brown coal may be processed and sold as raw humates, the extracts, sold as soluble humates, are a handy food concentrate for actinomycetes and mycorrhizal fungi, which are amongst the most important microorganisms for nutrient retention and delivery in the soil. Soluble humates and raw humates are excellent for buffering boron and trace elements such as copper, zinc, manganese, or sea minerals. They also are helpful when adding bulk minerals such as gypsum, silica rock powders, lime, rock phosphate, or potassium sulphate. Trace elements may be combined with 250 kilograms per hectare (250 pounds per acre) of raw humates or 25 kilograms per hectare (25 pounds per acre) soluble humate extracts in dry blends, or they may be dissolved in liquid soil drenches with soluble humates and water. This delivers them to the soil’s fungi, which hold on to and deliver them to plants. Crusher Dusts Siliceous rock powders such as granite or basalt crusher dusts only provide silicon from the surfaces of their particles, but they can be helpful in repairing silicon deficiencies while the soil biology starts releasing the soil’s silicon reserves. Siliceous rock powders can be fed to the soil biology along with humates as a food source, and the actinomycetes and mycorrhizae will gradually weather the particle surfaces and release silicon. Crusher dusts are especially effective when fed to pigs and their manure is composted. They also can be added to composts or spread along with composts. Generally 2 or 3 tons per hectare will produce a helpful response, and these rock powders also usually release boron, which is especially essential for legumes. Lime, Rock Phosphate, Potassium Sulphate, etc. Each of these has its own story, and, as Pfeiffer discovered, the soil total test is a better indication of whether these are needed than the soluble test. If deficient, any of these can be built into soils by inputs, with the caveat that it is not a good idea to add bulk lime to composts. Lime should not be added to compost at more than 0.1 percent of the total mass, as it tends to drive off nitrogen as ammonia. It can be spread along with composts, but when added to composts at more than 1 kilo per ton it tends to waste valuable nitrogen. Visual Soil & Crop Assessment Visual soil assessment is helpful in order to evaluate soil biology. New Zealand soil scientist Graham Shepherd has published a book on this titled Visual Soil Assessment Volume 1: Field Guide for Cropping & Pastoral Grazing on Flat to Rolling Country. While it may not be the last word on the subject, it is a surprisingly good start toward evaluating soils, their conditions, and their biological activity. This system assesses texture, structure, porosity, mottling, soil color, earthworm activity, aroma, root depth, drainage, and vegetative cover. There also are many visual clues to mineral deficiencies. For example, hollow stem clover, lucerne, beans, and potatoes indicate boron deficiency. Boron deficiency is also indicated by high Brix in the early morning, which shows that plants are holding their sugars in the foliage and the cycle of root exudation is not occurring at night. Dwarf leaves in clover indicate zinc deficiency. Purpling of grass and clover in winter indicates copper deficiency, and so on. Poor chlorophyll development and pale, yellowish green vegetation often indicate magnesium deficiency on a magnesium-rich soil. This is common where the soil is too sulfur deficient to release magnesium properly. Under these conditions, foliar analysis usually shows high sulfur because what little sulphate is present is soluble and plants take it up even though there is not enough in the soil for magnesium release. This slows growth and sulfur builds up in the plant because it is not being used. Adding magnesium to a high mag soil will only make matters worse, while the real cause of magnesium deficiency is the first priority of all soil amendment programs — sulfur. Soil consultant Noel Garcia, with Texas Plant & Soil Lab, speaks at the 2014 Eco-Ag Conference & Trade Show, on the Critical Growth Stages for Optimum Production. (1 hour, 15 minutes.) Listen in as he teaches a class on how to monitor plants for stress, and mineral and nutrition deficiencies. The taste and smell of vegetation can be clues of excess nitrate uptake and poor photosynthesis, while complex, delicious flavors and aromas indicate high Brix and nutritional density. Biodynamic growers should be aware that their own senses can be the best guide to determining what is going on with pastures and crops. Sending soil and plant specimens to laboratories for analysis is a useful tool for learning what the senses reveal, but firsthand observation is quicker as well as less expensive, and it can be far more informative. Nitrogen Fixation and Silicon Release Nitrogen and silicon are present in enormous abundance, though this usually goes ignored. Nitrogen fixation and silicon release should be the highest priority in agricultural research. If growers knew how to access nitrogen and silicon in abundance, it would eliminate the larger part of their fertilizer costs, to say nothing of most of the rescue remedies for weeds, pests, and diseases. Unfortunately, little funding is available for such research since industrial concerns would suffer if this knowledge became widespread. The nitrogen fertilizer industry currently uses 10 units of methane to manufacture 1 unit of ammonia. With a little more energy, this can then be converted into urea and applied as fertilizer. With straight urea applications to the soil, losses of 50 percent and more are normal, since large amounts of nitrogen evaporate as nitrous oxide (N2O) when the urea oxidizes. The same 10 to 1 carbon to nitrogen ratio holds true for biological nitrogen fixation since it takes 10 units of sugar from photosynthesis to fix 1 amino acid. However, the losses are nowhere near as great. The grower’s challenge is making photosynthesis as efficient as possible so that biological nitrogen fixation is abundant. Nitrogen fixation is more robust when plants have steady access to all the necessary requirements for efficient photosynthesis. This feeds a steady abundance of carbohydrates to their microbial nitrogen-fixing partners in return for amino acid nitrogen. Biodynamic farms attain this level of mineral balance and photosynthetic efficiency when everything is working near optimum. This deserves replicated scientific trials, but it hardly makes sense to wait for funding when there isn’t any money to be made from the research. Farmers must simply try their hand at it. Some will undoubtedly succeed with relative ease while others will find it difficult for a variety of reasons. Silicon, Nitrogen, and the Soil Food Web The previous subheading on soil testing indicates optimum levels of minerals for plant efficiency and nitrogen fixation. Though these guidelines are generally higher than those considered adequate in chemical agriculture, these levels are desirable for efficient photosynthesis, especially at lower temperatures. This is particularly true for silicon, which is almost always deficient in conventionally-farmed soils. Silicon, and its co-factor, boron, are the principal keys to transport speed, which is the key to abundant photosynthesis in plants. Energy must be transferred from the chloroplasts in the leaf panel to the leaf ribs where sugars are made. Silicon is basic to fluid transport, and this transport determines how fast sunlight is converted into sugar. Nitrates, nitrites, and other nonorganic forms of nitrogen impair the silicon chemistry of the plant as well as the symbiosis between plants and their microbial partners in the soil — unlike amino acid nitrogen, . Raw manures and poorly composted manures, especially raw poultry manure, are extremely detrimental because of the nitrate burden they impose on the soil biology. Nitrates flush silicon out of both plants and soils. How well a plant picks up silicon from the soil depends, at least in part, on the level of actinomycete activity at its roots. This in turn depends on the extent to which the soil opens up and is aerated, which in turn depends on sulfur levels and soil microbes such as Archaea that digest siliceous rocks. The sensitive biochemistry of these activities, in both soils and plants, is impaired by high levels of nitrates. Animal activity in the soil around plant roots provides freshly digested amino acid nitrogen, which encourages the release of silicon from the surfaces of soil particles. Living in partnership with plant roots, actinomycetes form fine fuzz along the root exudate zone of young roots, and nitrogen-fixing microbes make this their home. In the process, the actinomycetes utilize the silicon and boron in forming their fine, fuzzy hairs. As roots age and mature, these microbes are consumed by soil animals ranging from single-celled protozoa upward. The nutrients they excrete are taken up as nourishment by plants, often providing a high proportion of amino acid nitrogen and amorphous fluid silicon. Soil microbial life can only access silicon at the surfaces of soil particles where moisture, air, and warmth interact. The rest is locked up. Nitrogen fertilizers, particularly nitrates, suppress actinomycete development and the nitrogen-fixing microbial activity they host. On the other hand, if actinomycete activity is robust, the soil food web freely provides a luxury supply of both amino acids and amorphous fluid silicon. Biodynamic practices promote this activity as a way to achieve quality production that sustainably and efficiently rivals the yields of chemical agriculture. The bonus comes when environmental conditions are less than ideal. Biodynamic production can then easily surpass chemical yields. Hugh Lovel is an agricultural consultant serving clients in both the United States and Australia. He consults, speaks, and teaches on all aspects of agriculture. For more information, visit www.quantumagriculture.com. This article appeared in the July 2014 issue of Acres U.S.A.
The Soil Solution: 10 Keys By Graeme SaitFrom the June 2015 issue of Acres U.S.A. magazine Soil health directly affects plant, animal and human health. It also impacts topsoil erosion, water management and ocean pollution. Most importantly, it is now recognized that climate change is directly related to soil mismanagement. I believe a global soil health initiative can help save our planet. The Top Five Threats While in the UK, I met with a professor who shared some deeply concerning findings. He informed me that a recent survey of leading British scientists revealed that as many as one in five of the best thinkers in the country believe that we will be extinct as a species by the end of this century, or perhaps much earlier. This information should serve to spur meaningful action from every one of us. There are five core threats that need to be urgently addressed, and they all relate back to the soil. We have overtilled our soils, oxidized the humus and often ignored the replacement of key minerals that determine the health of humus-building microbes. Loss of Topsoil At the current rate of topsoil loss, we have just 60 years before the thin veil that sustains us is no more. This is a huge issue because we will hit the wall way before this six-decade deadline. What is driving this dramatic loss? Basically, it comes down to the massive decline in organic matter following the industrial, extractive experiment in agriculture. We have now lost more than two-thirds of our humus. Humus is the soil glue that determines whether rivers run brown following rainstorms or if the winds tear dust from the fragile upper layers of our food-producing soils. Nature teaches us that you must give to receive. However, this is not a lesson we have applied to our farmland. This universal law is at work in photosynthesis, the single most important process in nature. The plant pumps one-third of the sugars it produces from photosynthesis back into the soil to feed the microbes, which in turn fix nitrogen, deliver minerals and protect against plant and soil pests. It is a fairly basic concept that when you remove crops from a field, you are extracting carbon and minerals, and you cannot just keep taking indefinitely. Unfortunately, this has been the dominant model in many soils for the past century. We have overtilled our soils, oxidized the humus and often ignored the replacement of key minerals that determine the health of humus-building microbes. We have burnt out humus with excess nitrogen at the rate of 100 kg of carbon per every 1 kg of nitrogen oversupplied. We have removed massive amounts of minerals and carbon with ever-increasing yields from our NPK-driven hybridized crops. In many areas we continue to burn crop residues. This senseless practice floods the atmosphere with CO2, which should have been returned to the soil as humus. Burning also damages soil life while scorching precious organic matter in the process. The loss of topsoil has been increasing for a century and now, with the challenge of climate extremes, it is accelerating. Soil health legislation is essential in all of the 30 countries I have visited in the past year, and in the International Year of Soils we all need to be pushing for a Soil Restoration Bill. Ocean Acidification The oceans have absorbed around half of the CO2 that has billowed from our soils, smokestacks and cement- makers over the past century. This is a planetary self-balancing mechanism, which has helped avoid a much higher global temperature increase. However, there has been a price to pay for this compensatory carbon redistribution. The CO2 becomes carbonic acid in the ocean and, as a result, our seas have become increasingly acidic. It is basic chemistry that creatures that make their outer shells from calcium struggle to do so in increasingly acidic conditions. This directly impacts coral, shellfish, phytoplankton, algae and krill, and their struggle for survival has already begun. The key understanding here is that their survival is actually our survival. Algae and krill are the basic building blocks for all life in the ocean. Phytoplankton produce 60 percent of the oxygen we breathe, and we have already lost 40 percent of these creatures. The latest figures show a 10 percent increase in global carbon emissions over this past year. This is the biggest single increase ever recorded. Ocean Warming Ocean warming is possibly the most urgent issue at present. Methane is a greenhouse gas that is 23 times more potent in thickening the heat-trapping blanket that warms our world compared to CO2. Permafrost is the phenomenon where ancient organic matter releases methane gas as the ice cover melts. There are currently huge, unanticipated outpourings of methane associated with the rapid thawing of Siberia. However, there is an even more threatening methane-driven phenomenon linked to the loss of ice in the arctic. The arctic oceans house mountains of methane and carbon sludge called methane hydrates. This material remains stable at the low temperatures and high pressure found at depths below 500 meters. However, it is now suggested that there will be no summer ice cover in this region within less than two years. This means that the arctic oceans, lacking the reflective effect of the ice cover, will warm much more rapidly. In a recent edition, the prestigious scientific journal Nature warned of a strong potential for a massive “methane burp” from this region within the next two or three years. They suggested that this “burp” could involve 50 gigatonnes of methane in one huge release. This is equivalent to 1150 gigatonnes of CO2. Here are some figures that help to put this huge release into perspective. The entire man-made contribution of CO2 to the atmosphere from industry, energy generation and transport since 1860 is 250 gigatonnes. The loss of two-thirds of our humus through soil mismanagement represents another 476 gigatonnes. We may be set to see the equivalent of over 150 percent more CO2 than that combined total, released in one short time frame. Food Security Food security and feeding the billions become increasingly serious concerns as climate change progresses. There is no country I have visited in the past 12 months that has not had serious issues linked to climate change. Brazil, with its biggest drought in 80 years; California, with a three-year killer drought; India, with a belated, substandard monsoon; and large areas of Asia, New Zealand and Australia impacted with unparalleled weather extremes. It is becoming increasingly likely that these climate-related issues could serve to trigger economic recession or depression. In uncertain economic times, you are absurdly vulnerable if you are a country like Qatar, with 6 percent of the food security of Japan, who produce just 40 percent of their own food requirements. Turmoil and international aggression come hand in hand with financial collapse — it is easy to shut down the imported food supply of another country when seeking to fast-track capitulation. Improving your food security becomes an urgent necessity in this brave new world. Soil health determines productive capacity. In fact, good soil and water are increasingly seen as “the new gold,” in recognition of their expanding importance. The GMO companies have sold us the story that their GM varieties are the solution to feeding a growing world population. However, it is becoming increasingly obvious that these finely tuned hybrids require very specific and precise conditions to deliver their promise. They can be very productive when given the correct fertilizer, moisture requirements and climate conditions, but they can really struggle in challenging conditions. They do not have resilience, and resilience is the single most important requirement in a world that is becoming considerably less predictable. The more mineralized and biologically active your soil, the greater the crop resilience. There are tens of thousands of examples of this phenomenon. In fact, the obvious validity of a soil health strategy could be clearly contrasted with the failings of the conventional approach in the face of changing conditions. The reality is this: the billions are better fed with humus-rich, living soils that store precious moisture more efficiently and sustain crops that can adapt to and perform in changing conditions. Declining Nutrition Declining nutrition in our food and chemical contamination of our fresh produce are two other closely-related issues impacting our sustainability. The industrial, extractive agriculture model has seen the constant removal of soil minerals and a loss of two-thirds of the humus that helps to store and deliver those minerals. It is common sense to recognize that every time we take a crop from a field, we are removing a little of all 74 minerals that were originally present in those soils. We replace a handful of them, often in an unbalanced fashion, and we assault our soil life with a smorgasbord of farm chemicals. When we have bombed the microbe bridge between soil and plant there is a price to pay. The plant suffers, in that it has less access to the trace minerals that fuel immunity, and the animals and humans eating those plants are also compromised. It has been suggested that the food we now consume contains just 20 percent of the nutrition found in the food consumed by our grandparents when they were children. The immune-compromised plant will always require more chemical intervention, and repeated studies have demonstrated the cumulative effect of chemical residues in our bodies. This serious scenario is all about minerals and microbes, and they, in turn, are housed by humus. Humus Saves the World It may seem like something of an oversell to claim that the sweet-smelling, chocolate brown substance that determines soil fertility could really pull us from the mire. The key understanding here involves recognition that you can’t make more carbon. The number of carbon molecules present on our planet has remained constant since the dawn of time. This carbon is either stored in the soil as humus, the carbon-based life forms, or the atmosphere as CO2, and it cycles between these three. The problem is that a great deal of the carbon that used to be in the soil as humus (over two-thirds) is now in the atmosphere, thickening the blanket and trapping more heat. The very simple and obvious solution is to return some of that excessive atmospheric carbon back to the soil as stable humus. When we build organic matter (humus) in the soil we have effectively sequestered carbon from the atmosphere. This is a difficult concept to grasp for some people, but if you realize that you can’t make more carbon, it becomes clear that if it is returned to the soil, it is also removed from the atmosphere. Professor Rattan Lal is, perhaps, the leading scientist driving this humus awareness. He has suggested that an increase in organic matter in the top 6 inches of the soil can effectively counter 30 percent of man-made carbon emissions. This is an extremely conservative estimate because carbon sequestration via humus-building happens at depths much greater than 6 inches. The roots of plants release glucose, created from photosynthesis, to feed the surrounding soil biology. Some of this glucose is converted to humus in the soil. In this context, root depth determines the depth and scale of carbon sequestration in the soil. The fact is that many plants have roots that extend much deeper than 6 inches. Recent studies, for example, have identified Australian native grasses with roots that extend well over 100 feet down into the soil. A review of recent climate change science reveals a common and depressing overuse of the term “irreversibility” in appraisals of our future. If we constrain ourselves to the concept of reducing carbon emissions as our sole action strategy, this negative appraisal may be justified. However, when humus-building is incorporated into that game plan, the story changes. A global increase of 1.6 percent organic matter is sufficient to reduce CO2 levels in the atmosphere from 400 ppm to below 300 ppm, which effectively reverses global warming. The burning question remains — how do we do this within the short time frame involved? Top 10 Solutions 1- Composting Composting becomes standard practice wherever it is possible. On every farm, every council and in every home garden, we should compost or add compost. Composting involves the conversion of organic matter into stable humus, but it is much more than that. When we add compost to a soil it stimulates and regenerates the soil life responsible for building humus. We did not just add some stable humus to our soil with the compost inclusion; we triggered our existing soil life to build humus much more efficiently and rapidly. The single most important breakthrough in the science of composting is the finding that the inclusion of 6-10 percent of a high-clay soil to the compost facilitates the creation of a clay/humus crumb where the humus created lasts for much longer in the soil. In fact, it remains stable in the soil for up to 35 years (compared to a bacterial-dominated compost, based on something like lawn clippings where this “active humus” is only stored in the soil for around 12 months). 2- Mycorrhizal funig Mycorrhizal fungi (AMF) become the most important creatures on the planet at this point in time. These endangered organisms, of which we have lost 90 percent in farmed soils, produce a sticky, carbon-based substance called glomalin. It is now understood that glomalin triggers the formation of 30 percent of the stable carbon in our soils. It is an inexpensive strategy to reintroduce these missing creatures to farmed soils. Recent research has also demonstrated that compost has a remarkable capacity to stimulate both existing mycorrhizal fungi and introduced AMF, so our first two solutions are inextricably intertwined (as are several of these proposed solutions). 3- Protection of soil life Protection of soil life, and their humus home base, becomes an essential strategy. There is little point in reintroducing beneficial microbes with one hand and then promptly destroying the new population with the other. How did we lose 90 percent of our AMF and seriously compromise cellulose-digesting, humus-building fungi in general? The use of unbuffered salt fertilizers dehydrates and kills many beneficials, overtillage slices and dices AMF and oxidizes humus, and we have often neglected to feed and nurture this important workforce. However, the single most destructive component of modern agriculture, in terms of soil life, has been farm chemicals. Some of the herbicides are more destructive than fungicides in removing beneficial fungi. Fungicides can sometimes take the good with the bad and nematicides are the most destructive of all chemicals. There needs to be legislation to regulate chemicals that are killing the microbes that may determine our long-term survival. In an extractive model, where the soil is viewed as an inert medium in which the plant stands, this has not been a concern. However, as the science floods in, we are thankfully recognizing the critical importance of the soil as a living medium and change is underway. 4- Carbon source A carbon source must be included with all nitrogen applications. If we investigate how we lost two-thirds of our soil carbon, it becomes apparent that mismanagement of nitrogen is a major player. This is not just an issue relevant to loss of carbon — agriculture currently contributes 80 percent of the greenhouse gas, nitrous oxide, which is 310 times more potent than CO2 in terms of its global warming side-effect. Here’s how it works: nitrogen stimulates bacteria, because these creatures have more need for nitrogen than any other organism (17 percent of their body is nitrogen). The bacteria seek carbon after this nitrogen feeding frenzy to balance out their unique 5:1 carbon to nitrogen ratio. In the absence of applied carbon, they have no choice but to target humus. They would never choose to literally eat themselves out of house and home, but we give them no choice. The destruction of humus via the mismanagement of applied nitrogen is a major factor that can be easily addressed. This is no small thing. Research demonstrates that we lose 100 kg of carbon for every 1 kg of nitrogen applied over and above what is required by the plant at the time. Think of large applications of starter N, where a young seedling cannot possibly utilize that much nitrogen. We need to regulate N applications, to adopt foliar application of N (which can be dramatically more efficient) and to include a carbon source with every nitrogen application. The carbon source offers an alternative to eating humus. This might include molasses, manure or compost or NTS Soluble Humate Granules, a carbon-dense source of concentrated humic acid, that also stabilizes and magnifies the nitrogen input. 5- Tillage Tillage must be modified. There is compelling research demonstrating the humus-building effect of no-till or minimum-till agriculture. Much of this comes from the Rodale Institute and their 25 years of in-depth research, quantifying humus-building dynamics. Every time we work the soil we disturb cellulose-digesting fungi and oxidize existing humus. I favor minimum-till over no-till, as there is evidence of mineral stratification that occurs over time in completely untouched soils. 6- Green manure and cover crops Green manure and cover crops must become indispensable carbon-building tools for all of us. There is a rural myth among some growers that, in dryland situations, these crops will steal moisture from the subsequent cash crop. This is not research-based. All of the evidence suggests that the increased moisture retention associated with this regular injection of organic matter more than compensates for the moisture removed in the production of the cover crops. There is compelling new U.S. research that cocktail cover crops may be particularly beneficial. It has been found that certain combinations of plants, typically involving cereals, grasses, brassicas, legumes and chenopods, can trigger the release of phenolic compounds from these plant roots, which have been shown to stimulate rapid humus building. The brilliant American consultant, Jerry Brunetti, has included a particularly successful cocktail cover crop recipe in The Farm as Ecosystem. Cocktail cover crops promote microbial biodiversity because each species tends to favor and feed specific groups of root organisms. The more diverse the plant species, the more varied the soil life — and nature thrives on biodiversity. The brassicas in the mix can also discourage pathogens like nematodes and some diseases with their biochemical root exudates. Cocktail cover crops are also profoundly drought protective, in that the great mass of roots involved exudes a gel-like mucilage that can absorb 10,000 times its own dry weight in water. The trillions of bacteria around the roots also release a gel-like substance that provides them protection from predators but also serves to retain water. Brunetti cites a cocktail mix that has proven tremendously successful for North Dakota farmer, Gabe Brown, who has, in turn, been inspired by the innovative work of Brazilian agronomist, Dr. Ademir Caligari. This mix includes at least a dozen of the following species: pearl millet, sorghum sudan grass, proso millet, buckwheat, sunn hemp, oilseed radish, turnips, pasha, ryegrass, canola, phacelea, cowpeas, soy beans, sugar beets, red clover, sweet clover, kale, rape, lentils, mung beans and subterranean clover. This mix includes the desired mix of legumes, grasses, cereals, brassicas and chenopods. It also involves cool season grasses and broad-leaved plants combined with warm season grasses. 7- Intelligent grazing Intelligent grazing must be encouraged or incentivized to the point of legislative management. Real science involves learning from the perfect blueprint of nature, rather than the futile attempt at improving upon nature that has characterized much of profit-based, scientific endeavor. In this context, we might examine nature to determine which soils on the planet have been most productive. The Great Plains captured more carbon and produced more biomass than any other region on Earth. This amazing productive capacity was driven by huge herds of bison that moved into one area for a day, depositing massive amounts of urine and dung and creating a seedbed with their hooves for improved germination of the diverse range of seeds present in their dung. In effect, they facilitated a cocktail cover crop, or pasture crop in this case. The herds tended to graze down to about 4 inches before moving on, almost as though they were aware of the fact that the leaf is the solar panel that fuels photosynthesis. A plant pumps down 50 percent of its photosynthates (glucose) to the roots, and 60 percent of this carbon is exuded into the soil (30 percent of total glucose production). The whole carbon-building mechanics of the pasture are impacted by the length of the leaf, because the roots, which are being fed by the leaves, prune themselves back in accord with leaf size. If you have grazed down to a bowling green, the root mass has reduced accordingly and you no longer have a carbon-building pasture. Researchers like Dr. Christine Jones in Australia have conclusively demonstrated that correctly managed pasture has the most carbon-sequestering capacity of any crop. Ruminants may yet be our savior, but only if we learn from nature and broadly adopt grazing practices where a post-grazing leaf length of 4 inches becomes the gold standard. 8- CAM plants CAM plants involve something called Crassulacean Acid Metabolism, where their stomates remain open during the night, but close during daylight. This allows much more efficient photosynthesis and much better water utilization (around 500 percent better). These plants thrive in hot, arid conditions, in low humus soils. Their role in these conditions is to maximize the benefits of minimal moisture, while pumping more sugars into the soil to build carbon in these barren soils. The good thing about these succulents is that they are absurdly easy to propagate. You simply break off a piece of plant and poke it into the soil. In suitable countries, the unemployed could plant trillions of these plants across areas that have been desertified by mankind’s footprint. We could improve those soils while sequestering massive amounts of carbon from the atmosphere. One of the CAM plants, surprisingly, is Moringa, which is one of the most nutrient-dense food plants on the planet. 9- Humates Humates become the most important of all farm inputs, from a humus-building perspective. Humic acid is the most powerful known stimulant of the cellulose-digesting fungi that build stable humus. It also holds seven times its own weight in water, which, of course, benefits crops and soil organisms. Humates improve root growth and soil structure and buffer the dehydrating (biocidal) impact of salt fertilizers. These inputs are effectively cost-neutral, so they remain a viable option even in subsistence farming. This “free” status is based upon the well-researched capacity of humates to magnify nutrient uptake by one-third, via a phenomenon called “increased cell sensitization.” Soluble humic acid granules are combined with fertilizers at the rate of 5 percent. The cost of this inclusion is deducted from the fertilizer bill (i.e., a little less fertilizer is used to accommodate the cost of the humate additive). The proven 33 percent increase in fertilizer performance ensures that there is no risk factor associated with the small reduction in applied fertilizer. Soil, plants, animals, humans and the planet can all be beneficiaries of what is essentially a cost-free input. 10- Biochar Biochar is based upon the discovery of terra preta soils in the Amazon that seem to be self-generating and expanding. They feature humus-rich topsoil meters deep and expand out beyond the villages from which they originated. It has been found that this remarkable fertility appears to originate from charcoal that was added to the soil from cooking fires. On the basis of this finding, the concept of manufacturing biochar as a humus-building soil additive has attracted considerable interest and associated research funds. I have been concerned that we have only embraced half of the story. The amazing terra preta soils must surely involve specific microbes in synergy with charcoal. We trialed a variety of task-specific organisms and broad-spectrum inoculums, like compost tea, in conjunction with biochar. However, we could not identify the specific synergy that turns biochar from inert carbon into a profound soil-building mechanism. I have had meetings with microbiologists who claim that the key synergist may be mycorrhizal fungi. Editor’s Note; This article appeared in the June 2015 issue of Acres U.S.A. magazine Graeme Sait is an internationally acclaimed author, educator and co-founder of Nutri-Tech Solutions (NTS). He has written hundreds of published articles and a popular book Nutrition Rules!. Graeme has formulated many of the soil health and human health products for which NTS are renowned and he has developed all of the nutrition programs that are the keystones of their proactive management approach. Visit www.nutri-tech.com.au.
Soil pH: Making Adjustments to Boost Fertility By Bill McKibben Soil pH adjustment may seem like a pretty straightforward operation, but there are many things to consider before undertaking such a bold step with soil chemistry. The first step is determine the direction you need to go and the products to use to achieve your goal. I cannot stress enough the importance of getting a good soil test. I’ve heard people say that based on the type of weeds or the fact that moss is growing means the soil pH needs adjusting. Assuming those statements were true, which direction and how much adjustment should be made? Without a good soil test it is pure and simple guesswork. Generally I prefer to see soil pH of 6.2 plus or minus two-tenths on soils with exchange capacities of 10 or higher. This does not apply to high organic matter soils with organic levels above 15 percent. These soils may slide down to a pH level of 5.5 or a little less and still have enough calcium and magnesium for adequate plant growth. At the low pH levels I become more concerned with manganese toxicity in the soil solution. I have experienced manganese toxicity on soils that have 5-8 ppm manganese levels on the standard soil test extracted with the Mehlich III. On light exchange capacity soils, I prefer pH to be 6.5 plus or minus two-tenths. There are two reasons for this slight increase in pH. The first is due to the low buffering capacity of sandy soils, which could result in a significant drop in the pH over a short period of time from manure or nitrogen applications as well as leaching. Secondly, it is especially difficult to maintain enough soluble calcium in solution in light, sandy soils. Soil expert and author William McKibben, The Art of Balancing Soil Nutrients, from the 2009 Eco-Ag Conference & Trade Show. (1 hour, 8 minutes). Listen in as McKibben talks about the steps you can take after you receive your soil test results to help balance your soil. For most soils the tendency is to see soil pH levels drop over time. This is primarily due to the loss of cations by crop removal, erosion and nitrogen displacement. Calcium, magnesium and potassium are the major cations affected by this removal process. Soils consisting of coral and calcareous sands have such large volumes of calcium in the base makeup of the soil that a drop in the soil pH may not be seen in one’s lifetime. It is for this reason that these calcareous soils, which may have pH levels around 7.5, cannot economically be adjusted downward. Raising soil pH is relatively inexpensive. Lime is the product of choice but there are two basic types of lime: high-calcium and dolomitic. Raising Soil pH Raising soil pH is the most common practice and is relatively inexpensive. Lime is the product of choice. There are two basic types of lime, high calcium and dolomitic. High calcium lime will normally test around 30 percent calcium and 3-5 percent magnesium, and dolomitic lime will test around 21 percent calcium and 12 percent magnesium. There are those who will say lime is lime so use whatever is closer to the farm. I prefer to balance the cations using William A. Albrecht’s ratios of 65 percent calcium and 15 percent magnesium base saturation. On soils with exchange capacities greater than 15, base saturations of magnesium greater than 20 tend to increase the tightness of the soil, resulting in more compaction issues and grass control problems. Neal Kinsey, Using Soil Analysis to Grow Crops, from the 2005 Eco-Ag Conference & Trade Show. (50 minutes, 12 seconds). Listen in as agronomist Neal Kinsey, the author of Hands-On Agronomy, teaches about how to test your soils, and use that data, to increase crop yield and decrease weed pressures. Depending on soil test data and the balance of the cations, either calcitic or dolomitic lime will be selected. If the magnesium base saturation is below 15 percent I start off with an application of dolomite lime. Assuming 2 tons of lime is needed to adjust the pH, the first ton would be dolomite and maybe a year later a ton of calcium. Lime applications need to be considered more like yearly fertilizer applications instead of a once every 3-5 year project. Putting on lime will impact the availability of potassium and especially phosphorus. Trace elements may also be affected by liming. Even though a soil may need 2 or 3 tons of lime, I prefer to limit most of my lime applications to 2,000-3,000 pounds-per-acre unless aggressive tillage will be performed. Since most farmers are going to no-till or minimum till, incorporation of the lime is very limited. This will reduce the solubility of the lime since the pH in the band at the surface will be rapidly increased. Gary Zimmer, Gaining a Working Knowledge of Calcium, from the 2008 Eco-Ag Conference & Trade Show. (56 minutes, 50 seconds.) Listen in as agronomist Neal Kinsey, author of Hands-On Agronomy, teaches a workshop on how available calcium in the soil can help drive all facets of soil nutrition. This layering of the lime could also affect the results of your next soil test if you are sampling deeper than what the lime has impacted in the soil. In the lab the soil will be ground and thoroughly mixed. Your results will show the soil as if it were a homogeneous mix when in fact you may have a layer of unreacted lime that was dissolved by the extracting solution, leading you to believe the nutrients are all available. This stratification is a real concern that is not being addressed in our no-till practices. Some new watershed data shows phosphorus levels in the water as high, and in some cases exceeding, the 1990 levels when no-till and minimum were not widely accepted practices. These issues could be alleviated with some aggressive tillage, even moldboard plowing every five or six years following wheat. This program would require immediate leveling and planting a good cover crop to prevent soil loss. The turf industry suffers from the same issues of stratification but only through aggressive core aeration and nutrient balancing of the top dressing materials can this be minimized. Besides considering the type of lime to be applied to the soil, the fineness of the lime is equally as important. I would prefer to see the lime ground to the point where 60-80 percent of the lime will pass a 60-mesh screen. The finer the lime, the more reactive the lime will be. The more reactive the lime, the smaller the applications should be but more frequent applications will be required. Fine limes do have one major drawback. The finer the limes the dustier they are and harder to spread in windy conditions. Spread widths should be adjusted to the finer portion of the lime and not the coarse particles. Lowering Soil pH Adjusting the pH downward with sulfur is recommended for calcareous soils and not for soils with a high pH as a result of sodium. High sodium levels as a result of irrigation water need to be flushed out through watering and possibly the use of gypsum rather than sulfur. Lowering pH is not generally done on a large-scale basis in general agriculture due to the cost factor. I have done it where a couple of acres were going to be planted to blueberries, gardens and turf situations. In agriculture situations where a farm has been over-limed, we generally increase phosphorus applications, preferably through starters and foliar feeding, along with foliar feeding traces. The use of more acidifying nitrogen sources during corn rotations is also beneficial. I prefer to lower pH levels over a period of a couple years so I can retest and monitor the progress. Attempting to lower the pH of calcareous sand-based soils is not feasible or economical. This article was first published in the March 2011 issue of Acres U.S.A. For more information, contact Logan Labs, LLC, P.O. Box 326, Lakeview, Ohio, 43331, phone 937-842-6100. For more information about soil pH, subscribe to Acres USA.
Fertile Soil: Understanding Fertility Levels and Inputs By Neal Kinsey Fertile soil is a goal of every farmer, gardener and orchardist, but achieving fertile soil and maintaining fertile soil takes some understanding of the soil ecosystem, including minerals, microbials and other inputs will affect your soil fertility. There are those in agriculture who insist that if you will only use the program they recommend, regardless of your farm’s condition, there will be no need to purchase phosphate and potassium and perhaps any other fertilizers anymore. Names of actual farmers successfully using such programs can be provided by the salesman. Some of these farmers have actually been able to maintain yields without the use of fertilizer for several years. Keep in mind that it is possible, under the proper conditions, to achieve excellent results without adding more fertilizer. But on most farms the proper conditions do not exist, and hardship would ultimately result for those involved in such a program. If a program to eliminate fertilizer is begun on highly fertile soils, it can look great for several years. If that same program is tried on a soil with very low fertility levels, that farmer is likely to become a victim within a few years — usually less than three. On a highly fertile farm it is possible to grow crops — sometimes several crops — without the use of fertilizer. But it is not possible to grow those crops without a sufficient level of soil fertility. In a given year, the farmer may be able to produce excellent crops without additional fertilizer, but this will not be accomplished without a sufficient level of fertility in the soil. Furthermore, that fertility must be maintained above a certain level, or the crops produced there will not continue to do their best. A farmer tosses a handful of soil. The only way to accurately determine whether this level is still there each year is by use of a soil test that provides a detailed fertility analysis. These tests should then make it possible to correctly identify soils that produce well versus soils with poor yields, just by looking at each soil analysis. Using such a detailed analysis of the soil, the formulation of a fertility program that will work best in all types of situations is possible. Neal Kinsey, Weeds and Soil Fertility, from the 2016 Eco-Ag Conference & Trade Show. (1 hour, 11 minutes.) Listen in as agronomist Neal Kinsey, author of Hands-On Agronomy, speaks about the relationship between soil health, soil nutrients and weed pressure. Using very detailed soil sampling and analysis techniques, farmers utilizing our testing program have tried various products in comparison to the normal methods of maintaining fertility levels. In every case, as crops were removed, the fertility levels would eventually begin to decline until yields were affected. The number of years that it took to noticeably affect the fertility depended on the nutrient levels present in the soil when the program was begun. For most soils, it required three years or less to see a decline in the general fertility levels, and on those with very low fertility, it happened the very first year. But for some of the best soils, the levels remained high for five years or longer without showing decline in general fertility. Fertile Soil is Always Changing These comments are not intended to even imply that there is no place for specialty products such as biological stimulants or broad-based nutrient materials that help to solve various needs or problems for a given soil. We discuss using various materials in Hands-On Agronomy, but readers should understand that there are circumstances surrounding changes in soil fertility which can sometimes be used falsely (whether intentionally or unintentionally) when a farmer decides to try a program which claims to eliminate the need for fertilizers or soil amendments. For example, as low calcium levels are increased by applying needed limestone, low phosphate levels will also tend to increase in the soil. Also when high magnesium levels and the soil pH drop at the same time, potassium levels will tend to increase. In actual fact, these increases can be expected to occur just by properly supplying the needed nutrients to the soil, and are not dependent on a specific product to eliminate the need for those materials. Neal Kinsey, Using Soil Analysis to Grow Crops, from the 2005 Eco-Ag Conference & Trade Show. (50 minutes, 12 seconds). Listen in as agronomist Neal Kinsey, the author of Hands-On Agronomy, teaches about how to test your soils, and use that data, to increase crop yield and decrease weed pressures. As another example, calcium levels, expressed as pounds of calcium per acre, can be shown to “increase” just by pulling the soil sample from the lighter areas of the field (shows lower exchange capacity and lower amount of available calcium) before using a program, and from heavier areas after using the program (shows a higher exchange capacity and higher amount of available calcium). Again, such situations have been used to claim a product or program decreases the need for limestone, whether or not the individual may have intended to be deceitful. If the cation exchange capacity on a soil test from the same field reads significantly higher than previous tests, it is most likely due to sampling in areas of the field with a higher clay content. Soils with a high clay content generally contain more pounds of calcium as a result of the clay’s ability to attract and hold more of it. No matter what program of soil fertility is used, you can never “get something for nothing.” What is taken from the soil must be returned or eventually a price will have to be paid. It is only possible to receive from the soil in the same manner that fertility continues to be provided to it. Farmers who have access to — or have in the past used — plenty of manure or compost on their farms come closest to being able to grow a crop without additional fertilizer. But even in such cases, most farmers still are not able to adequately supply all of the necessary nutrients for the crops they are striving to grow. For example, sulfur and boron seldom increase from manure application, due to very low levels in the manure and their tendency to leach from the soil. Some clients who have used manure and/or compost annually for several years have shown no increase in copper, manganese and/or zinc, while others show significant increases after two or three years. Soils can react differently to the very same type of fertilization. The real key to whether or not a farm needs additional fertilizer depends on the current level of fertility in the soil and on what elements are contained in that soil to be released through the action of the biology and chemistry of the soil. Maintaining Fertile Soil On soils that have moderate or higher fertility levels, the approach to maintaining adequate fertility should always be to “feed” the soil and let the soil “feed” the crops to be grown there. This “feeding” is done by providing the necessary nutrients in the proper amounts for the soil on which crops of whatever kind are to be grown. Feed the soil and let the soil feed the plants. Programs which recommend a certain number of pounds of any nutrient per acre for a crop, no matter what the soil conditions, have forgotten this basic principle. Establishing the necessary levels of nutrients in each soil should be based on the specific needs of that soil. This is accomplished by use of broadcast applications, especially in regard to any “long-term influence” types of fertilizer. Some fertilizers are “soil builders,” providing long-term influence toward fertility of the soil (these will build the available nutrient levels in the soil under proper conditions). Other fertilizers are only “plant feeders” (no soil build-up). Such fertilizer programs are trying to second guess the basic soil needs and provide a “shortcut” to production. They strive to by-pass the biology of the farm soil and put on only what the plant itself will take up. This includes side-dressing, in-row fertilization, and trying to establish various ratios of one nutrient to another based solely on the measurement of the level of one or more of the elements present in that soil. Neal Kinsey, Compost & Manure Analysis, from the 2005 Eco-Ag Conference & Trade Show. (50 minutes, 39 seconds.) Listen in as agronomist Neal Kinsey, author of Hands-On Agronomy, speak about how to test compost and manure to ensure it is adding balance to your soil, and not throwing your soil and crops out of balance. Such programs may have to be used in certain cases for short-term situations, but for a program intended to build the soil fertility levels, these will not generally be as satisfactory, and should be avoided wherever possible. Some fertilizer salesmen will insist that building a quality soil is too expensive, but those who have accomplished such will verify that it is not. In fact, in the long run it is by far the most economical method of maintaining top fertility and crop yields. Keep in mind that the soil is alive with biological activity. This soil life is a vital part of building and maintaining soil fertility for growth and production. When you try to feed the plant and neglect the rest of the soil’s biological life year after year, it is a mistake which will rob nutrients from all such living organisms and restrict them from performing whatever they are specifically designed to accomplish in the soil. The soil is the plant’s stomach. Feed the soil to keep it vibrantly alive and working as it should. Feed the soil and the soil will do by far the best job of feeding the plants to be grown there. It is generally understood that fertilizers, limestone, manures and any other materials can add to the fertility level of a soil when supplied in the amounts actually needed. But what seems hardest for most growers to comprehend is that when too much is applied any one of these same nutrients can damage soil fertility levels. This specifically has to do with the fact that overuse of any of the major or secondary nutrients (lime, N, P, K & S) can affect the availability of the micronutrients or trace elements to the crop. These trace elements, especially if levels are borderline in the soil, can be tied up by the “glut” caused from an unusually large amount of a specific nutrient in the area where the plant roots must feed. This can happen either from broadcasting far too much of a product, or from too much side-dress or in-row material. For example, too much nitrogen ties up available copper, and too much calcium can tie up iron, manganese copper, zinc and/or boron. The same thing can happen in regard to the use of manures. The P & K levels in a good productive soil that receives manure can be raised enough to increase the availability of these nutrients in larger amounts than the crop takes out. Compost can do the same thing. Applying Manure or Compost When it comes to applying manure or compost, don’t overdo a good thing. Too much can be detrimental to crop yields, just the same as not using enough can hurt production on a field. As a rule of thumb, fields that already test high in phosphates and/or potassium should not receive indiscriminate applications of manure or compost. Only when a soil test shows the soil is ready to receive more manure or compost should an application of either one be considered. For example, if a farmer continues to apply manure or compost, increases unneeded phosphate availability, and copper or zinc levels are barely adequate in comparison, the phosphate can interfere with the uptake of these two minor elements. This overuse can cause the crop being grown there to be short of these needed micronutrients, and the problems that result from it. For example, copper provides resilience to the plant and is necessary along with potassium and manganese for strong stalks and wood. Zinc is needed for moisture uptake by the plant. Excessive phosphate levels in the soil will impede the uptake of zinc and may also affect copper levels in crops such as citrus. This can affect the productive ability of the plants growing there and also the nutritional value when consumed by animals or mankind. As potassium levels continue to rise from too much manure or compost, boron and manganese uptake can be restricted. If excessive enough (especially in lighter soils), a magnesium deficiency can be caused by too much available potassium in the soil. In addition, on some soils, manure or compost can unduly increase available zinc levels. When not too high, this is fine, but when zinc is already very high in a soil, this can begin to cause problems associated with zinc toxicity, and particularly phosphate tie-up. Keep in mind that where manure or compost has been used repeatedly and must be stopped, the amount of nitrogen which would have been supplied by the manure must be made up from other sources on those crops with high nitrogen requirements. Too much manure and/or compost, just like anything else that is excessively used, can cause problems. Those who have access to large amounts of manure or compost with only a small acreage or a garden need to especially heed the lessons of too much manure. Not only can excessive use of manure increase P and K levels and hinder the uptake of micronutrients in the soil; it can also contribute to health problems for those who rely heavily on those areas for sustenance. Some indications that the problem is very advanced in gardens include bitter tasting cucumbers, squash and even turnips in certain cases. The only sure way to know how much manure is enough on any soil is to take an accurate soil test, and, if the soil tests relatively high in fertility, a fertilizer analysis of the manure you are using. This should be an analysis which shows the saturation each soil contains in terms of calcium, magnesium, potassium and sodium. Phosphate content should be measured. Combined with an analysis which shows the content of major and secondary elements in the manure or compost to be used, it is then possible to know what conditions are present in the soil and what can be expected to happen if the material is applied. Still, there is no need to shy away from the use of compost and manure in the fields or on the garden. So long as a proper analysis of each soil is completed, and so long as that analysis is correctly interpreted in terms of the amount needed. Too much of a particular type of fertilizer can hurt yields and/or crop quality just as much as too little fertilizer can hurt them. Some growers fail to learn this until it is too late. Be safe with fertilizer and manure applications. Know you can use them profitably before they are applied. Only by developing a program of detailed testing and analysis on your soils can you know this for sure. If you have a program of soil fertility that is working well for you, continue to develop and perfect it. If you don’t have such a program, now is the time to begin one. As a sign in the office of one of my clients reads, “Stand for something — or you will fall for anything.” Base your stand on high fertility levels, not just high rates of fertilizer. By Neal Kinsey. This article was originally published in the September 1999 issue of Acres U.S.A. Learn about healthy soil with Acres U.S.A. this summer The second annual Healthy Soil Summit is a virtual event held this August 25-26, 2020. It will consist of 2 days of high quality soil health content. Klaas Martens will be the keynote speaker. Learn more about the Healthy Soil Summit here.
Soil Restoration: 5 Core Principles By Christine Jones Soil restoration is the process of improving the structure, microbial life, nutrient density, and overall carbon levels of soil. Many human endeavors — conventional farming chief among them — have depleted the Earth to the extent that nutrient levels in almost every kind of food have fallen by between 10 and 100 percent in the past 70 years. Soil quality can improve dramatically, though, when farmers and gardeners maintain constant ground cover, increase microbe populations, encourage biological diversity, reduce the use of agricultural chemicals, and avoid tillage. Soil restoration begins with photosynthesis. The Power of Photosynthesis Imagine there was a process that could remove carbon dioxide (CO2) from the atmosphere, replace it with life-giving oxygen, support a robust soil microbiome, regenerate topsoil, enhance the nutrient density of food, restore water balance to the landscape, and increase the profitability of agriculture. Fortunately, there is. It’s called photosynthesis. In the miracle of photosynthesis, which takes place in the chloroplasts of green leaves, CO2 from the air and H2O from the soil are combined to capture light energy and transform it into biochemical energy in the form of simple sugars. These simple sugars — commonly referred to as photosynthates — are the building blocks of life. Plants transform sugar into a great diversity of other carbon compounds, including starches, proteins, organic acids, cellulose, lignin, waxes, and oils. Fruits, vegetables, nuts, seeds, and grains are packaged sunlight derived from photosynthesis. The oxygen our cells and the cells of other living things utilize during aerobic respiration is also derived from photosynthesis. Significantly, many of the carbon compounds derived from the simple sugars formed during photosynthesis are also essential to the creation of well-structured topsoil. Without photosynthesis there would be no soil. Weathered rock minerals, yes… but no fertile topsoil. The Plant-Microbe Bridge It comes as a surprise to many that over 95 percent of life on land resides in soil, and that most of the energy for this amazing world beneath our feet is derived from plant carbon. Exudates from living roots are the most energy-rich of these carbon sources. In exchange for ‘liquid carbon,’ microbes in the vicinity of plant roots — and microbes linked to plants via networks of beneficial fungi — increase the availability of the minerals and trace elements required to maintain the health and vitality of their plant hosts (1,2). Bruce Tainio: Amending Soil Microbial Life, from the 2005 Eco-Ag Conference & Trade Show. (1 hour, 2 minutes) Listen in as the popular agronomist explains how to feed the microbial life in your soil, and develop optimal microbial biodiversity. Microbial activity also drives the process of aggregation, which enhances soil structural stability, aeration, infiltration, and water-holding capacity. All living things — above and below ground — benefit when the plant-microbe bridge is functioning effectively. Sadly, many of today’s farming methods have severely compromised soil microbial communities, significantly reducing the amount of liquid carbon transferred to and stabilized in soil. This creates negative feedbacks all along the line. Over the last 150 years, many of the world’s prime agricultural soils have lost between 30 and 75 percent of their carbon, adding billions of tons of CO2 to the atmosphere (3). The loss of soil carbon significantly reduces the productive potential of the land and the profitability of farming. Soil degradation has intensified in recent decades — around 30 percent of the world’s cropland has been abandoned in the last 40 years due to soil decline (4). With the global population predicted to peak at close to 10 billion by 2050, the need for soil restoration has never been more pressing. Soil dysfunction also impacts human and animal health. Nutrient Depletion In Our Food Over the last 70 years, the level of every nutrient in almost every kind of food has fallen between 10 and 100 percent. This is an incredibly sobering fact. An individual today would need to consume twice as much meat, three times as much fruit, and four to five times as many vegetables to obtain the same amount of minerals and trace elements available in those same foods in 1940. Dr. David Thomas (5,6) has provided a comprehensive analysis of historical changes in food composition from tables published by the Australian Medical Research Council, the Ministry of Agriculture, the Ministry of Fisheries and Foods, and the Food Standards Agency. By comparing data available in 1940 with that in 1991, Thomas demonstrated a substantial loss in mineral and trace element content in every group of food he investigated. The nutrient depletion summarized in Thomas’ review represents a weighted average of mineral and trace element changes in 27 kinds of vegetables and 10 kinds of meat: 5. Mineral Depletion in Vegetables (1940-1991; average of 27 kinds of vegetables):Copper – declined by 76%Calcium – declined by 46%Iron – declined by 27%Magnesium – declined by 24%Potassium – declined by 16% 6. Mineral Depletion in Meat (1940-1991; average of 10 kinds of meat):Copper – declined by 24%Calcium – declined by 41%Iron – declined by 54%Magnesium – declined by 10%Potassium – declined by 16%Phosphorus – declined by 28% Significant mineral and trace element depletion was also recorded in the 17 varieties of fruit and two dairy products tested over the same period (5). The mineral depletion in meat and dairy reflects the fact that animals are consuming plants and/or grains that are themselves minerally depleted. In addition to the overall decline in nutrient density, Thomas found significant changes in the ratios of minerals to one another. Given that there are critical ratios of minerals and trace elements for optimum physiological function, it is highly likely that these distorted ratios have an impact on human health and well-being (5). Restoring Nutrient Density to Our Food It is commonly believed that the significant reduction in the nutrient density of today’s chemically-produced foods is due to the dilution effect. Dilution occurs when yields rise but mineral content falls. Significantly, though, vegetables, crops, and pastures grown in healthy, biologically active soils do not exhibit these compromised nutrient levels. Only in rare instances are minerals and trace elements completely absent from soil. Most of the “deficiencies” observed in today’s plants, animals, and people are due to soil conditions not being conducive to nutrient uptake. The minerals are present in the soil but are simply not plant-available. Adding inorganic elements to correct these so-called deficiencies is an inefficient practice. Instead we need to address the biological causes of dysfunction. Around 85 to 90 percent of plant nutrient acquisition is microbially-mediated. The soil’s ability to support nutrient-dense crops, pastures, fruits, and vegetables requires the presence of a diverse array of soil microbes from a range of functional groups. The majority of microbes involved in nutrient acquisition are plant-dependent. That is, they respond to carbon compounds exuded by the roots of actively growing green plants. Many of these important groups of microbes are negatively impacted by the use of “cides” — herbicides, pesticides, insecticides, and fungicides. In short, the functioning of the soil ecosystem is determined by the presence, diversity and photosynthetic rate of actively growing green plants — as well as the presence or absence of chemical toxins. But who manages the plants and the chemicals? You guessed it… we do. Fortunately, consumers are becoming increasingly aware that food is more than a commodity (7). It is up to us to restore soil integrity, fertility, structure, and water-holding capacity — not by applying Band-Aids to the symptoms, but by better managing our food production systems. The Soil Carbon Sink Soil can function as a carbon source — adding carbon to the atmosphere — or a carbon sink — removing CO2 from the atmosphere. The dynamics of the source/sink equation are largely determined by land management. Over the millennia a highly effective carbon cycle has evolved, in which the capture, storage, transfer, release, and recapture of biochemical energy in the form of carbon compounds repeats itself over and over. The health of the soil and the vitality of plants, animals, and people depends on the effective functioning of this cycle. Technological developments since the Industrial Revolution have produced machinery capable of extracting vast quantities of fossil fuels from beneath the Earth’s surface as well as machinery capable of laying bare large tracts of grasslands and forests. This has resulted in the release of increasing quantities of CO2 into the atmosphere while simultaneously destroying the largest natural sink over which we have control. The decline in natural sink capacity has amplified the effects of anthropogenic emissions. Many agricultural, horticultural, forestry, and garden soils today are a net carbon source. That is, these soils are losing more carbon than they are sequestering. The potential for reversing the net movement of CO2 to the atmosphere through improved plant and soil management is immense. Managing vegetative cover in ways that enhance the capacity of soil to sequester and store large volumes of atmospheric carbon in a stable form offers a practical and almost immediate solution to some of the most challenging issues currently facing humankind. The key to successful soil restoration and carbon sequestration is to get the basics right. Five Principles for Soil Restoration Green is good — and year-round green is even better Photosynthesis draws hundreds of billions of tonnes of CO2 from the atmosphere every year. The impact of this reduction was dramatically illustrated in a stunning visualization released by NASA in 2014 (8). The movement of carbon from the atmosphere to soil — via green plants — represents the most powerful tool we have at our disposal for the restoration of soil function and reduction of atmospheric CO2. While every green plant is a solar-powered carbon pump, it is the photosynthetic capacity and photosynthetic rate of living plants (rather than their biomass) that drive the biosequestration of stable soil carbon. Photosynthetic capacity is the amount of light intercepted by green leaves in a given area (determined by percentage of canopy cover, plant height, leaf area, leaf shape and seasonal growth patterns). On agricultural land, photosynthetic capacity can be improved through the use of multi-species cover crops, animal integration, multispecies pastures, and strategic grazing. In parks and gardens, plant diversity and mowing height are important factors. Bare soil has no photosynthetic capacity. Bare soil is also a net carbon source and is vulnerable to erosion by wind and water. Photosynthetic rate is the rate at which plants are able to convert light energy to sugars. It is determined by many factors, including light intensity, moisture, temperature, nutrient-availability and the demand placed on plants by microbial symbionts. The presence of mycorrhizal fungi, for example, can significantly increase photosynthetic rate. Plants photosynthesising at an elevated rate have a high sugar and mineral content, are less prone to pests and diseases, and contribute to improved weight gains in livestock. Photosynthetic rate can be assessed by measuring Brix with a refractometer. An increase of around 5 percent in global photosynthetic capacity and/or photosynthetic rate would be sufficient to counter the CO2 flux from the burning of fossil fuels, provided the extra carbon was sequestered in soil in a stable form. This is feasible. On average, global cropland is bare for around half of every year (9). If you can see the soil, it is losing carbon! Both photosynthetic capacity and photosynthetic rate are strongly impacted by management. Leading-edge light farmers are developing innovative and highly productive ways to keep soil covered and alive, while at the same time producing nutrient-dense food and high-quality fiber. Grazing Management Figure 1: Growth of both tops and roots is significantly impaired if more than 50 percent of the green leaf is removed in a single grazing event. This topic requires far more space than is available, but it is vitally important that less than 50 percent of the available green leaf be grazed (see figure above). Retaining adequate leaf area reduces the impact of grazing on photosynthetic capacity and enables the rapid restoration of biomass to pre-grazed levels. Over a 12-month period, significantly more forage will be produced — and more carbon sequestered in soil — if pastures are grazed tall rather than short. In addition to leaf area, pasture height has a significant effect on soil building, moisture retention, nutrient cycling, and water quality. To maintain photosynthetic capacity (and to ensure rapid recovery) it is highly beneficial to remove livestock from a pasture before you can see their feet. Regenerative grazing can be extremely effective in restoring soil carbon levels deep underground. The deeper the carbon, the more it is protected from oxidative and microbial decomposition. The sequestration of most significance is that which occurs below 30 cm (12). Crop Production Increasingly sophisticated machinery and a plethora of “cides” have provided the means for the planet’s rapidly expanding population to create bare ground over billions of acres, dramatically reducing global photosynthetic capacity. Reduced levels of photosynthesis have in turn resulted in reduced carbon flow to soil, significantly impacting soil and landscape function and farm productivity. Organic carbon holds between four and 20 times its own weight in water. This means that when carbon levels are depleted, the water-holding capacity of the soil is significantly compromised. Low water-holding capacity results in poor structural stability when soils are wet and reduced plant growth when soils are dry. One of the most significant findings in recent years has been the improvements to infiltration, water-holding capacity, and drought-resilience when bare fallows have been replaced with multi-species covers. This improvement has been particularly evident in lower rainfall regions and in dry years (13). Microbes matter A healthy agricultural system is one that supports all forms of life. All too often, many of the life-forms in soil have been considered dispensable. Or, more correctly, they have not been considered at all. The significance of the plant-microbe bridge in transferring and stabilizing carbon in soil is becoming increasingly recognized. The soil microbiome is now heralded as the next frontier in soil restoration research. One of the most important groups of plant-dependent soil-building microbes are mycorrhizal fungi. These extraordinary ecosystem engineers access water, protect their hosts from pests and diseases, and transport nutrients such as organic nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, iron, and essential trace elements including copper, cobalt, zinc, molybdenum, manganese and boron — all in exchange for liquid carbon. Many of these elements are essential for resistance to pests and diseases and climatic extremes such as drought, water-logging, and frost. When mycorrhizal symbiosis is functioning effectively, 20-60 percent of the carbon fixed in green leaves can be channelled directly to soil mycelial networks, where a portion is combined with biologically-fixed nitrogen and converted to stable humic compounds. The deeper in the soil profile this occurs the better. Humic polymers formed by soil biota within the soil matrix improve soil structure, porosity, cation exchange capacity, and plant growth. Soil function is also strongly influenced by its structure. In order for soil to be well-structured, it must be living. Life in the soil provides the glues and gums that enable soil particles to stick together into pea-sized lumps called aggregates. The spaces between the aggregates allow moisture to infiltrate more easily. Moisture absorbed into soil aggregates is protected from evaporation, enabling soil to remain moist for longer after rain or irrigation. This improves farm productivity and profit. Well-structured soils are also less prone to erosion and compaction, and they function more effectively as bio-filters. Sadly, many of the microbes important for soil function have gone missing in action. Can we get them back? Some producers have achieved large improvements in soil health in a relatively short time. What are these farmers doing differently? They diversify. Diversity is indispensable Every plant exudes its own unique blend of sugars, enzymes, phenols, amino acids, nucleic acids, auxins, gibberellins, and other biological compounds, many of which act as signals to soil microbes. Root exudates vary continuously over time, depending on the plant’s immediate requirements. The greater the diversity of plants, the greater the diversity of microbes, and the more robust the soil ecosystem. The belief that monocultures and intensively managed systems are more profitable than diverse biologically based systems does not hold up in practice. Monocultures need to be supported by high and often increasing levels of fertilizers, fungicides, insecticides, and other chemicals that inhibit soil biological activity. The result is even greater expenditure on agrochemicals in an attempt to control pests, weeds, diseases, and the fertility issues that ensue. The natural grasslands that once covered vast tracts of the Australian, North American, South American, and sub-Saharan African continents — plus the “meadows” of Europe — contained several hundred different kinds of grasses and forbs. These diverse grasslands and meadows were extremely productive prior to simplification through overgrazing and/or cultivation. Figure 2: Triticale monoculture (left) suffering severe water stress while triticale sown with other species (right) is healthy. In addition to triticale, the “cocktail crop” contains oats, tillage radish, sunflower, field peas, faba beans, chickpeas, proso millet and foxtail millet. Innovative farmers are experimenting with up to 70 different plant species to see which combinations perform best for soil restoration. Some grain and vegetable producers are setting aside up to 50 percent of their cash crop area for multi-species diverse soil primers. They believe the benefits far outweigh the costs. It has been reported that two full seasons of a multispecies cover can perform miracles in terms of soil health. Mixtures of peas with canola, clover or lentils with wheat, soybean and/or vetch with corn, and buckwheat and/or peas with potatoes are becoming increasingly common. The integration of animals into cropland can also be extremely beneficial. This doesn’t need to be complicated, though. Something as simple as including one or two companions with a cash crop can make a world of difference. As well as improving soil function, companion plants provide habitat and food for insect predators. Recent research (15) has shown that as the diversity of insects in crops and pastures increases, the incidence of insect pests declines, reducing the need for insecticides. An aspect of plant community structure that is gaining increased research attention is the presence of ‘common mycorrhizal networks’ (CMNs) in diverse pastures, crops and vegetable gardens. It has been found that plants in communities assist each other by linking together in vast underground super-highways through which they can exchange carbon, water and nutrients (16,17). CMNs increase plant resistance to pests and diseases (18), enhance plant vigor, and improve soil health. In my travels I’ve seen many examples of monocultures suffering severe water stress while diverse multi-species crops beside them remained green (see photo above). In mixed-species plantings, warm-season grasses (such as sorghum and maize) are the most generous ‘givers’ to soil carbon pools, while broadleaf plants benefit the most from the increased availability of nutrients. In livestock production systems, animal health issues linked to lack of plant diversity (and hence animal nutrition) can often mean the difference between profit and loss. Chemical use can be dangerous Living soils can significantly improve the mineral cycle. Researchers have shown, for example, that mycorrhizal fungi can supply up to 90 percent of plants’ nitrogen (N) and phosphorous (P) requirements (20). In addition to including companions and multi-species covers in crop rotations, maintaining a living soil often requires reducing the application of high-analysis synthetic fertilizer and other chemicals. Profit is the difference between expenditure and income. In years to come we will perhaps wonder why it took so long to realize the futility of attempting to grow crops in dysfunctional soils, relying solely on increasingly expensive synthetic inputs. No amount of NPK fertilizer can compensate for compacted, lifeless soil with low wettability and low water-holding capacity. Indeed, adding more chemical fertilizer often makes things worse. This is particularly true for inorganic N and P. An often-overlooked consequence of the application of high rates of N and P is that plants no longer need to channel liquid carbon to soil microbial communities in order to obtain these essential elements. Reduced carbon flow has a negative impact on soil aggregation and limits the energy available to the microbes involved in the acquisition of important minerals and trace elements. This increases the susceptibility of plants to pests and diseases. Inorganic Nitrogen The use of high-analysis N fertilizer poses a significant cost to both farmers and the environment. Only 10 to 40 percent is taken up by plants, which means that 60 to 90 percent of applied N is lost through a combination of volatilization and leaching. It is often assumed that nitrogen only comes from fertilizer or legumes. But all green plants are capable of growing in association with nitrogen-fixing microbes. Even when N fertilizer is applied, plants obtain much of their N from microbial associations. Farmers experimenting with yearlong green farming techniques are discovering that their soils develop the innate capacity to fix atmospheric nitrogen. If high rates of N fertilizer have been used for a long time, though, it is important to wean off N slowly, as free-living nitrogen-fixing bacteria require time to re-establish. Another of the many unintended consequences of the use of nitrogen fertilizer is the production of nitrous oxide in water-logged and/or compacted soils. Nitrous oxide is a greenhouse gas with almost 300 times the global warming potential of carbon dioxide. Inorganic Phosphorous The application of large quantities of water-soluble P, which is found in fertilizers such as in MAP, DAP, and superphosphate, inhibits the production of strigolactone, an important plant hormone. Strigolactone increases root growth, root hair development, and colonization by mycorrhizal fungi, enabling plants to better access phosphorous that is already in the soil. The long-term consequences of the inhibition of strigolactone include destabilization of soil aggregates, increased soil compaction, and mineral-deficient (e.g. low selenium) plants and animals. In addition to having adverse effects on soil structure and the nutrient density of food, the application of inorganic water-soluble phosphorus is highly inefficient. At least 80 percent of applied P rapidly adsorbs to aluminium and iron oxides and/or forms calcium, aluminum, or iron phosphates. In the absence of microbial activity, these forms of P are not plant-available. It is widely recognized that only 10-15 percent of fertilizer P is taken up by crops and pastures in the year of application. If P fertilizer has been applied for the previous 10 years, there will be sufficient P for the next 100 years, irrespective of how much was in the soil beforehand. Rather than apply more P, it is more economical to activate soil microbes in order to access the P already there. Mycorrhizal fungi are extremely important for increasing the availability of soil P. Their abundance can be significantly improved through cover crops, diversity, and appropriate grazing management. Avoid aggressive tillage Tillage may provide an apparent quick-fix to soil problems created by lack of deep-rooted living cover. Repeated and/or aggressive tillage increases the susceptibility of the soil to erosion, though. It also depletes soil carbon and organic nitrogen, rapidly mineralizes soil nutrients (resulting in a short-term flush but long-term depletion), and is highly detrimental to beneficial soil-building microbes such as mycorrhizal fungi and keystone invertebrates such as earthworms. The increased oxidation of organic matter in bare soil from tillage, coupled with reduced photosynthetic capacity, not only adds carbon dioxide to the atmosphere but may also contribute to falling levels of atmospheric oxygen. Conclusion All food and fiber producers — whether grain, beef, milk, lamb, wool, cotton, sugar, nuts, fruit, vegetables, flowers, hay, silage, or timber — are first and foremost light farmers. Since the Industrial Revolution, human activities have sadly resulted in significantly less photosynthetic capacity due to the reduced area of green groundcover on the Earth’s surface. Human activity has also impacted the photosynthetic rate of the groundcover that remains. Our role, in the community of living things of which we are part, is to ensure that the way we manage green plants results in as much light energy as possible being transferred to — and maintained in — the soil battery as stable soil carbon. Increasing the level of soil carbon improves farm productivity, restores landscape function, reduces the impact of anthropogenic emissions, and increases resilience to climatic variability. It is not so much a matter of how much carbon can be sequestered by any particular method in any particular place, but rather how much soil is sequestering carbon. If all agricultural, garden, and public lands were a net sink for carbon, we could easily reduce enough CO2 to counter emissions from the burning of fossil fuels. Everyone benefits when soils are a net carbon sink. Through our food choices and farming and gardening practices we all have the opportunity to influence how soil is managed. Profitable agriculture, nutrient-dense food, clean water, and vibrant communities can be ours… if that is what we choose. The author extends special thanks to Sarah Troisi for expert technical assistance with the photographs used in this article. Soil ecologist Dr. Christine Jones works with innovative farmers and ranchers to implement regenerative land management practices that enhance biodiversity, nutrient cycling, carbon sequestration, productivity, water quality, and community and catchment health. She launched Amazing Carbon (www.amazingcarbon.com) as a means to share her vision and inspire change. In 2005, Dr. Jones held the first of five “Managing the Carbon Cycle” forums to promote the benefits of soil carbon. Over the past decade she has gained international recognition as a speaker. She was also the keynote speaker at the 2017 Acres U.S.A. Eco-Ag Conference & Trade Show in Columbus, Ohio, and taught a course on restoring diversity to agricultural soils during Eco-Ag University. This article originally appeared in the October 2017 issue of Acres U.S.A. magazine. Literature cited: 1. Jones, C.E. (2008). Liquid carbon pathway. Australian Farm Journal, July 2008, pp. 15-17. 2. Kaiser, C., Kilburn, M. R., Clode, P. L., Fuchslueger, L., Koranda, M., Cliff, J. B., Solaiman, Z. M. and Murphy, D. V. (2015), Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation. New Phytologist, 205: 15371551. doi:10.1111/nph.13138. 3. Lal, R., Follett, R.F., Stewart, B.A. and Kimble, J.M. (2007). Soil carbon sequestration to mitigate climate change and advance food security . Soil Science, 172 (12), pp. 943-956. doi: 10.1097/ss.0b013e31815cc498 4. Pimentel, D. and Burgess, M. (2013). Soil erosion threatens food production. Agriculture 2013 , 3, 443-463; doi:10.3390/agriculture3030443 5. Thomas, D.E. (2003). A study of the mineral depletion of foods available to us as a nation over the period 1940 to 1991. Nutrition and Health, 17: 85115. 6. Thomas, D.E. (2007). The mineral depletion of foods available to us as a nation (1940-2002) a review of the 6th Edition of McCance and Widdowson. Nutrition and Health , 19: 21-55. 7. Latham, J. (2016). Why the food movement is unstoppable. Independent Science News. https://www.independentsciencenews.org/health/why-the-food-movement-is-unstoppable/ 8. Miller, P. (2014). Stunning NASA visualization reveals secret swirlings of carbon dioxide. https://www.nasa.gov/press/goddard/2014/november/nasa-computer-model-provides-a-new-portrait-of-carbon-dioxide/ 9. Siebert, S.; Portmann, F.T.; Döll, P. Global Patterns of Cropland Use Intensity. (2010). Remote Sensing, 2 (7), 1625-1643; doi:10.3390/rs2071625 10. Voth, K. (2015). Great “Grass Farmers” Grow Roots. National Grazing Lands Coalition. 11. Crider, F.J. (1955). Root growth stoppage resulting from defoliation of grass. U.S. Department of Agriculture Technical Bulletin 1102, 23 p. babel.hathitrust.org 12. Jones, C.E. (2011). Carbon that counts. New England and North West Landcare Adventure 16-17 March 2011. amazingcarbon.com 13. Weller, J. (2015). Testimony to House of Representatives Committee on Agriculture bipartisan subcommittee on Conservation, Energy and Forestry hearing on the Benefits of Promoting Soil Health in Agriculture and Rural America. 14. Natura, H. (undated). Illinois Native Plant Guide. Root systems of prairie plants. nrcs.usda.gov 15. Lundgren, J.G and Fausti S.W. (2015). Trading biodiversity for pest problems. Science Advances 1(6). doi: 10.1126/sciadv.1500558 16. The Plant Guy (2012). Plant Social Networks- is this why companion planting & inter-cropping work? 17. Walder, F., Niemann, H., Natarajan, M., Lehmann, M.F., Boller, T. and Wiemken, A. (2012). Mycorrhizal networks: Common goods of plants shared under unequal terms of trade. Plant Physiology , 159(2): 789797. doi: 10.1104/pp.112.195727 18. Johnson, D. and Gilbert, L. (2014). Interplant signalling through hyphal networks. New Phytologist, 205(4): 1448-1453. doi: 10.1111/nph.13115 19. Kelly (2014). Who knew? Cover crop cocktails are commune hippies. 20. Smith, S.E, Read, D.J. (2008). Mycorrhizal Symbiosis, 3rd Edition. Academic Press.
Sourcing Fertility in the Soil By Charles Walters and Esper K. Chandler The book Ask The Plant is based on the agronomy of Esper “K.” Chandler, and offers farmers and growers a better way to grow plants that involves reading the unique language of plants, utilizing leaf and petiole testing, and in turn knowing how to produce a better crop using only the fertilizers and soil-building ingredients that are truly needed, when they are most needed. Instead of following the decades-old conventional model where plants are given copious amounts of soluble nitrogen fertilizers aimed to force-feed the landscape green, Ask the Plant addresses how to build a healthy soil without excessive inputs. After more than seven decades of soils being mined not replenished, especially of organic matter and minerals — it is time to “ask the plant” and find out what our crops and soils are really telling us so we can produce a better crop using only what is truly needed. The excerpt below discusses soil minerals, including issues, ideal levels and requirements. From Chapter 6: Sourcing Fertility There may be many troublesome words in modern agriculture, but none glows in the dark as much as “conventional.” How a recently minted term such as “conventional” came to label practices less than 60 years old in agriculture, a practice that goes back 10,000 years, surely must puzzle etymologists. Nevertheless, we appear to be stuck with the word, and might as well examine it in the context of modernity. Calcium (Ca) “On any soil on any continent,” says Chandler, “we are required to look at the available calcium level, which is possibly the most variable of the elements required for crop growth.” The needs of the soil dictate the kind of lime to be applied. Some soils have fairly good magnesium. Therefore, calcareous sources of lime ask for evaluation. There are many such sources, Chandler cautions. He cites oyster shells, even caliche, and if magnesium is deficient, then high-magnesium limestones are needed. What, then, is dolomitic lime and what is high-magnesium lime? In Texas, dolomitic lime is notoriously absent, but there are natural lime deposits of 8, 10, and 11% magnesium. “Get to know your highway department because they know where the deposits are,” farmers are often told, and it’s valid advice. “In Texas,” Chandler explains, “most of the local limestone is used in roadbed construction. The Texas-Louisiana Aglime and Fertilizer Association, supported largely by the Sneed family of Georgetown, Texas pioneered the agricultural lime business, supporting research, education, and quality programs for generations. But then when we go to agricultural lime, an overriding factor is the fineness of the grind.” Specifically, it must be ground as finely as talcum powder if it is to be reactive. This is a basic problem. Chandler learned back in his experimental station days that Arkansas dolomite lime ground only to the fineness of beach sand would have little to no effect on pH. This meant more fineness was needed. Such a grind takes a generation of weathering to be useful. But lime with the consistency of talcum powder goes to work quickly as microbes break it down to help neutralize the soil’s natural acidity. The classes and sources of limestone are too numerous to catalog in one sitting. Just the same, mere consideration of the subject makes it necessary to determine what is available to the plant. Or, as Chandler recites, “You have to ask the plant whether indeed it is getting the calcium.” The Rio Grande Valley has soils with 4,000 to 10,000 ppm cation exchange capacity calcium, based on conventional testing. Still, calcium- deficient crops grow on that soil. The lesson is clear. Without the required amount of calcium available, how can such an overload be released? The problem is staggering in its dimensions. Soils well endowed with calcium often produce hungry plants because that prince of nutrients is not available. Conventional agriculture asks for water solubility, and yet the natural product often is not water-soluble. In any case, conventional testing does not look at water solubility (available H2O/Ca). That’s the why and wherefore of calcium, the major building block of all life. Many soils are not well endowed with calcium. Even if measured, the calcium is often not available. The one lesson commercial farming has to face tells us more than a lot of farmers want to know about those microbes. The microbes alone can slowly regenerate the fertility of the minerals. The business of extracting the minerals is one of nature’s finest accomplishments. Humus and calcium have an intractable partnership in good soil tilth. Calcium is often called the VIP of minerals. Calcium takes top billing in some lab recommendations after humus. Here, gypsum enters the fray. Chandler puts it this way, “The overriding factor in getting calcium available is converting it to an available form of calcium-sulfate as gypsum. Enter the sulfur content coming from the natural degradation of organic matter, which contains the sulfur nutrient, or it has to come from elemental sulfur itself.” Magnesium (Mg) The process of loading the soil colloid with an available form of calcium is crucial to cell life. Soil biology is a major factor. From there, the equation progresses to the magnesium factor. Magnesium is not as major an element, but it commands a ratio and has an essential function. Thus, the hunt for sources of magnesium calls up Epsom salts. Magnesium sulfate is a primary source, as is the mined naturally occurring mineral called Sul-Po-Mag and K-Mag, which is sulphate of potash magnesium. When conventional agriculture made its case, the rush was on to buy up either magnesium deposits or vulnerable competitors. Magnesium is a finite resource. This reality had smaller companies finding and exploiting smaller veins, now dominated by the marketing name of K-Mag. Potassium (K) The next major fertility requirement is potash, often available as K2O. Most sugar crops require more potash than nitrogen. Potash is a natural, mined mineral. It is not a rare earth, but it calls for entrepreneurial skill and dedication to wrest it from the earth. Deep-vein, hot- water mining in Canada has placed high-cost extraction in the United States onto the back burner. “I’m told that we have some deep deposits of potash in the Rocky Mountains. It can be mined using Canadian technology,” Chandler points out, citing the method that has been proved. Chandler is more than a little concerned about the future of fertilizer inputs, not because of technology that powders, prills, and otherwise refines the materials for field distribution, but because sources are finite and use is often wasteful. “We have natural deposits of potash,” Chandler reminds, “from the desert and Dead Sea areas where it has accumulated due to a natural distillation process. These materials have ample amounts of other minerals as well. So, there are many sources of potash, but it is the economic considerations that usually prevail.” As an aside, Chandler explains the range of the subject to natural/organic folks who often want to prohibit the use of potassium chloride because of the chlorine. This, in excess, is a problem. Unfortunately, “you run the cost up to the natural/organic grower when he or she has to turn to more costly sources of potash,” reminds Chandler, “and potash is one of the largest quantity elements necessary for production of all crops.” Some soils are well endowed with potash as measured by almost any laboratory inventory, but is it available? And even more important, how can it be made available? To ask these questions is to suggest the availability of an answer. Here is where natural/organic insight comes to the rescue. These denizens of the academic underworld forced down the throats of academia the come-lately consideration of humus, the food for microbial balance in the soil for release of minerals and plant nutrients. A natural mineral that once figured in the research of William A. Albrecht is langbenite, more commonly known as Sul-Po-Mag, and now as K-Mag. Chandler has extensive experience with this mined product. Langbenite is the basis for both chemical and organic agriculture. It is, as the secondary name implies, a balance of sulfur, potash and magnesium. Unfortunately, many of the owners of such mines have relegated K-Mag to the back burner of company economics. This means little or no investment in production facilities. Cargill controls both ends of major production. As it stands, fertilizer fabricators literally synthesize the natural product much as they do all salt fertilizers. The label misleads farmers who often burn crops because they believe the label, thinking their purchase is the real thing. Most of the firms that control mineral resources are busily consolidating, as the saying goes, “into a few strong hands.” The process erases competition, establishes administered prices, and relies on the old iron law of “What will the traffic bear?” Chandler sharply defines secondary minerals as absolutely essential, the primaries being NPK. (“Potash”) Chandler seldom drops the fertilizer subject or the laboratory equivalent thereof without a word on potassium. Potassium is the largest cation in almost any plant. It usually accounts for more pickup than nitrogen. This appears to be a strange statement since nitrogen has the reputation as a dominant element. There seems to be a natural antagonism between potash and phosphorus. The two are constantly trying to tie each other up, and nature loves balance as much as fecundity. Now the sequence becomes clear. That overload of phosphorus supplied at the beginning of the year tends to run out. Electrical charges figure, most notably the penchant of potassium to tie it up. As phosphorus uptake falters, so does yield. Small amounts of phosphorus in the drip line along with humic acid doubles the phosphate uptake. Moreover, merely using humic acid can deliver as much phosphate to the petiole as a smaller amount of phosphate alone. The two together seem to double the P uptake. This achievement, faced off against the usual research-proven 5-15 percent P uptake, confers an efficiency on precision agriculture only wished for by staid conventional farmers. Chandler asserts that the above procedure with seaweed hormones and soil inoculants, all together, have quadrupled the effects of available phosphorus. When phosphorus is taken up, so too climbs the uptake reading of nitrogen and all other nutrients. Now Albrecht’s sage observation kicks in. Plants in touch with exchangeable nutrients have the capacity for manufacturing their own hormone and enzyme systems, which are needed to challenge insect predators and crop diseases. Want more? Buy this book here. About Charles Walters Charles Walters Charles Walters was the founder and executive editor of Acres U.S.A. He penned thousands of articles on the technologies of organic and sustainable agriculture and authored many books on the subject, including Weeds: Control Without Poisons, Dung Beetles, Grass, the Forgiveness of Nature, A Farmer’s Guide to the Bottom Line, Fertility from the Ocean Deep, as well as many others. A leading proponent of raw material economics, he served as president of the National Organization for Raw Materials (NORM) and authored several books on economics, including Unforgiven: The American Economic System Sold for Debt and War. About Esper K. Chandler Esper K. Chandler Esper K. Chandler was a professional agronomist and soil scientist who traveled the country consulting with growers in a quest to improve yields, quality, and profits. He was the owner of TPS Lab for more than 27 years. K. Chandler was a founding member of the National Oraganic Standards Board and a Certified Professional Agronomist (CPAg) by the American Society of Agronomy. He has been proclaimed as a leader in the soil fertility and plant nutrition field. Chandler passed away in 2008.