Subsoil: Digging Deep into Hardpan without Over-Tilling

Subsoil: The term implies tilling in an out-of-sight area called the “subsoil.” Building these zones may be the most important tillage practice, and it also may be the least understood. To understand why it is necessary to till the subsoil, we must first look under the ground into the real world of agriculture.

We will find mysterious things lying underground that can severely limit yields, regardless of how well we have managed the surface zone. Let us begin by taking a slice of the soil to see what is under there. The farmer should begin by looking for evidence of worm activity in the upper 6 to 12 inches of soil. Worms are a beautiful sight for those who understand their value. Their burrows enhance soil aeration and soil fertility. The burrow linings thrive with microbial activity. Once the soil passes through a worm’s digestive tract, the castings will be much higher in nutrients such as phosphorous and potassium than the nearby undigested soil.

We may also see a number of vertical holes that are formed by a different worm, commonly called the “night crawler.” These holes may be as large as 3/8 inch in diameter and extend from the surface to deep into the subsoil. In other areas we may not find night crawlers because while some soils may have them, others do not.

Understanding why you till and how deep to till are important

As we dig deeper, we often see the dark topsoil abruptly end. And as we dig more holes, we become even more aware of the various depths of the dark topsoil.

Prairie grasses form a deep, dark topsoil because they have massive root systems that regenerate annually. The grass roots have decayed annually over thousands of years and have formed a black soil that is high in humus and extends to the depth the grass roots can grow.

Identifying the Hardpan

You will be able to tell where the natural pan starts by identifying where the black soil stops. The natural pan was in place before the prairie grasses became established. Prairie grass roots, just like the roots of our agricultural crops, could not penetrate the pan.

Unlike prairie soils, timber soils do not form a dark topsoil, for two major reasons.

First of all, grasses, with their extensive root systems, do not grow under the shade of a thick forest. And second, tree roots are woody structures that live for many years. As a result, there is little decay under the ground, and humus cannot accumulate. Trees drop their leaves onto the surface of the soil, and therefore do not form deep humus layers.

As we look into a 24- to 30-inch hole, we will see several different soil layers. The only exception to this would be if it is “muck” soil or has been windblown or water-deposited.

Subsoil lies under the topsoil, and the soils finally grade into glacial till or glacial rubble that has not yet had time to transform into soil. As we look into the underground soil profile, we know that the soil has been there for 10,000 to 12,000 years, since the last glacier receded. During this time span, it has become what we call “middle- aged,” having a serious problem in the “waist” area.

Soil ecosystems are composed of combinations of various-size particles such as sand, silt and clay. Because of the different amounts of rain that fell over thousands of years, the water has moved the smallest particles downward to different depths.

This settling, plus chemical cementing, has formed a zone that is more dense than the soil above or below it. In most Midwestern soils, the bottom of this layer varies from 12 to a little over 20 inches below the surface. This belt-line bulging of finer particles is the reason these soils are considered “middle-aged.”

The primary reason for deep tillage is to make a slot through this dense, natural layer so that roots and water can enter freely into the subsoil. With this hardpan in place, we are farming with both roots and water up, on top of the hardpan, making our crops vulnerable to weather extremes of either flood or drought. As we carefully dig a cross-section of the soil, we may find roots making a right angle, running along the top of this hardpan.

This is a sight you will not forget, because it is convincing beyond doubt that a problem exists. This root- and water-limiting barrier may be our number-one yield-limiting factor, because it places a farmer at the mercy of weather extremes.

Testing for Tillage Depth

To deep-till correctly, a farmer must know the depth of the problem and make certain the zone-builder penetrates through it. Also keep in mind, when using either a penetrometer or knife, the soil must be moist. A pan cannot be found in dry soil because the profile will be too hard for either a knife or penetrometer to move through. Dry soil particles will not separate easily.

A penetrometer can be used to locate the depth of a hardpan. It can be slowly pushed into moist soil until a resistance point is reached. The resistance point will be the pan. The penetrometer can then be pushed until it abruptly breaks through. At this point, the bottom of the hardpan, or “breakthrough depth,” is reached and can be measured.

If it is difficult to find the pan with a penetrometer, we turn to a second instrument, a knife. A hole 2 feet or more in depth can be dug with a spade or posthole auger. Then a strong-bladed knife is inserted 2 to 3 inches into the sidewall near the bottom of the hole. It is pulled slowly upward, and as it reaches the pan, it will suddenly be nearly impossible to pull further. The knife test is the simplest and surest way to find the bottom of the pan.

Here are some rules to observe when building your zones:

  • Determine the depth of the natural pan to make certain the shanks of your zone-building equipment penetrate at least 1 inch below it.
  • Make a narrow slot through this zone without bringing subsoil to the surface.
  • There is no advantage in using a shank point more than 2 inches in width.
  • Build your zones when the soil is moist. Moist soil requires less horsepower and will cause less wear on the points.
  • With some exceptions, zone-building should be done in the fall.

Tilling in Clay Subsoils

Soils that crack open under dry conditions contain clay. Clay expands when it is wet and shrinks when it dries, to form drought or shrinkage cracks.

Drought cracks may be over 2 inches wide and extend down as far as 3 feet. While you may think this gives a subsoiling effect, it does not, because the clay expands when it becomes wet, and the crack will close again. Since clay is the smallest particle of soil, it is the one that settles downward first. In a clay soil, the pan will be so solid that it must be slotted through when the soil is moist and the clay expanded.

The shank on your zone-building equipment will remove an expanded clay core, leaving a void that can be filled with normal soil. When the soil next dries, the slot will become wider and will not close when it becomes wet. If you “shatter” this clay zone when it is dry, the shatter lines will swell shut when it rains, in the same manner as a drought crack.

With certain exceptions, we recommend zone-building in the fall on medium- to heavier-textured soils in order to prevent the severe wheel-track compaction that can occur if it is done in the spring.

Determining Slot Placement and Depth

Correct positioning of the slots is important. Let us assume you farm a corn-soybean rotation and both are planted in 30-inch rows. You also plan to pursue the entire zone-building system next season. Your first priority is to purchase the equipment necessary to begin zone-building. This first step should be done immediately after harvest, because the slots that are built will set the stage for a successful zone- management system for the crops that follow.

Make an all-out effort to cover your entire farm. This operation is so important that you should follow the combine, running the equipment around the clock if necessary.

Soybeans will normally be harvested ahead of corn. It is important to start zone-building on the soybean ground where corn will be planted the following year. Soybeans appear to stand drought a little better than corn, so by zone-building the soybean ground ahead of the corn crop, you will protect the corn from weather extremes.

This does not mean, however, that you should stop zone-building after completing the soybean stubble areas. You must also immediately work the cornstalks with the purpose of covering the entire farm.

Exactly where should the zone-built slots be placed? They should be placed directly into the center of the last year’s rows and directly under where the following year’s soybean rows will be planted. These narrow slots will be hard to see when you go to the fields next spring with your entire system.

Stay in the center of the rows while planting. Don’t think you can plant corn back into the old corn rows. This has often been tried, with a resulting loss of yield. Remember, our first Tillage Commandment states that we cannot allow our tillage system to place limits upon yields.

We want to leave the old corn or soybean root mass to decompose without being disturbed. These roots decompose to provide nutrient-laden passageways deep into the soil for the following season’s growing crops.

Let us assume you have zone-built slots on 30-inch spacings across your entire farm. Are you now through deep tilling? The answer is no, because you must start over the following year in the 1-year-old decayed rows. After this, you will have a slot every 15 inches.

Keep in mind that the top priority is to place a slot every 30 inches during the first year. The goal of 15 inches apart is not quite so urgent, but it should be completed even if it takes two or more years to finish.

Let us assume your soybeans are drilled. In this situation, you put markers on the zone-building equipment and begin slotting the drilled soybean stubble just as if you were operating the corn planter. Be certain to remember on which side of the field you started, and start planting on that same side.

You may think you do not drive straight enough to keep the slots under the planter rows. Don’t worry, because those slots will still do the job even if they wander 4 to 8 inches from the rows.

The 15-inch slot spacing is as important for drilled crops as for wide-row crops. The roots of every drilled row will enter these slots and plunge into the subsoil to provide the crop with true protection from weather extremes.

Another factor we must address is the depth of the tines. Remember that most farms have a natural pan with bottom levels that range between 12 and 20 inches from the surface. In most Midwest soils that were formed in place, we find the bottom of the pan at 16 to 18 inches. This can vary, depending upon erosion or soil deposition.

We explained earlier how to use the knife test to find the bottom of your soil’s pan. If the depth is 17 inches, you will need to make certain your zone-building equipment runs 18 inches deep. It is essential to penetrate through the pan so the roots and water can enter the subsoil.

Subsoil Benefits Under the Row

The third question inquires about the function of the slots. A complete understanding of these will hurry you into the fields to zone-till.

Let us begin by visualizing the zone-tilled area with slots directly under the rows and spaced 15 inches apart across your entire farm. In effect, there is a funnel under the rows that allows roots and water to be funneled directly into the subsoil below.

Imagine this funnel effect on the crop throughout the season. In the spring, the soils will warm much faster because the system manages soil aeration, soil water, soil organism activity and the adsorption of heat. It takes many more BTUs to heat water than to heat the same volume of soil.

By keeping the soil moisture at full-field capacity, soils will heat up very quickly in sunlight. Once the soil water exceeds the maximum capillary thickness that a soil particle can hold, the free water begins to accumulate in the soil’s air spaces. This causes the heat requirement for soil warming to increase dramatically and also prevents air exchange which further slows soil warming.

The “funnel effect” causes the water to soak into the subsoil to keep the lower water reservoir fully charged. This, along with deep roots, allows crops to produce abundantly during periods of drought, in comparison to those crops being farmed with their roots and water “up.”

On average, because of hardpans we farm only to a depth of 8 to 12 inches. Every time this top zone floods with water, all of the oxygen is driven from the soils. Roots cease functioning after two to four days of flooding, and nutrient and water uptake is drastically reduced. Worse yet, the root hairs on the outer root tips die.

Root hairs are the only part of the roots that adsorb nutrients and water. Certain mycorrhiza root fungi attach to the older roots and adsorb some nutrients in exchange for sugar from the root. These organisms also suffer when the air spaces flood with water. Anything that causes soils to become anaerobic can stop all nutrient uptake from the root hairs and symbiotic fungi attached to the roots.

Once the water drains and air reenters the soil, the root ends must begin to grow so they can develop new root hairs for nutrient and water adsorption. Soil life, which includes the root fungi, also takes time to recover.

This recovery time required for new root growth and soil life to return represents a loss of growing time. The plants have undergone stress and a degree of permanent damage that can reduce yields even though growth returns. Action must be taken to reduce the impact of this type of stress.

It is an interesting observation that depending upon the temperature, plants can thrive in flooded areas for approximately three days before they start to wilt while standing in water. It takes a few days for the oxygenated rainwater to run out of oxygen. Hydroponic plants can continue thriving while their roots are in nutrient-laden water as long as the water is oxygenated.

The point to be made is this: Every time soils flood or become waterlogged, we can easily lose seven to 10 days of growing time. If we can eliminate this loss of growing time by using a zone-tillage system, we can dramatically increase yields.

The final yield of a crop reflects the total amount of effective growing time it has during the season. We may be losing as much as 40 to 50 percent of a season’s growing time, because of the many yield-limiting factors we have failed to remove.

The slot that enters into the subsoil directly under the row removes many major yield-limiting factors. For example, corn growing over a such a slot will have its roots into the subsoil by the time it is 12 to 15 inches tall. These slots are the heart of the system and eliminate the most serious yield-limiting factors associated with air and water management.

By Donald R. Schriefer. This article was originally published in the October 2000 issue of Acres U.S.A.

Tillage for Healthy Soil

By Donald L. Schriefer

As a beginning, we understand that to effectively manage the below-ground environment we must attend to four essential areas. These are:

  1. soil aeration,
  2. soil water,
  3. soil life, and
  4. soil fertility

These are the four cornerstones of our entire farm operation. Our farming success will be in direct proportion to our understanding and ability to manage each of these important areas.

Soil aeration

We must be as attentive to soil aeration as we are to assur­ing an adequate air supply to the cylinders of our tractor engines. Soil life, root growth, water and nutrient uptake are all oxygen-demanding processes.

The importance of nutrient uptake by the roots can be compared to a vacuum cleaner and its filters. A vacuum cleaner cannot gather things if its filters are plugged. Sufficient mois­ture and oxygen around the roots turns them into efficient vacuum cleaners in the gathering of soil nutrients and water.

Gas diffusion is a law of gasses which states: “Gasses diffuse from an area of higher concentration to an area of lower con­centration until pressure equalizes in all areas.”

Since oxygen is much higher in the atmosphere than in the soil, it makes every effort to diffuse into the soil. As more oxy­gen is used in the soil by roots and soil life, more carbon dioxide is released into the soil air. The high concentration of carbon dioxide within the soil then diffuses into the atmosphere, where the process of photosynthesis turns it into sugar to be used by the plants. This all happens during the growing season, when plants need all of the carbon dioxide they can get.

Crops such as corn need this additional supply of carbon dioxide since there is not enough in the atmosphere alone to produce the high yields desired. The gas diffusion process is dependent upon the loosening effect of the soil through correct use of tillage and the actions of soil life.

Soil water

Correct management of soil water involves three major principles. These are:

  • Under normal circumstances, rainfall and irrigation water must be able to penetrate into the soil where it falls.
  • The penetrating water must also be able to move downward into the subsoil.
  • In addition to water, the roots of crops must also have unrestricted access into the subsoil.

We must face two major problems in our search for ways to manage water, with the first being a recognition that almost all soils have a natural barrier of compacted soil particles that restrict roots and water from freely entering into the subsoil. Because of this natural barrier, we can make only limited use of the subsoil and are basically forced to farm with both roots and water in the “up” position.

Second, our cultivation practices impart massive compac­tion, mismanage residue, and severely limit the activities of soil life. As a result, soil seals over to become very dense and allow the water to run off. This promotes excessive erosion and pol­lution of waterways.

The soil decay system

Our third critical area of management is taking care of crop residue and its decomposition.

Figure 24 (below) illustrates how an untreated fence post decomposes from the soil surface downward 3 to 5 inches. In untilled soil, this is the most biologically active zone. However, deep, penetrating roots can carry biological activity all the way into the subsoil.

Decay zone for a fence post at soil line

Positioning residue on and near the surface ensures its decomposition, which releases nutrients and carbon dioxide, improves soil tilth, and imparts many other benefits to the soil-plant system.

On our list of “cornerstones” which include soil aeration, soil water, soil life and fertility, we have placed soil fertility last. This is not to diminish it in importance, but rather, to empha­size that pouring on fertilizer is not a guarantee of high yields.

We must judge a soil’s fertility based upon how well our crops respond to that fertility rather than by soil test results alone. Certain things must be addressed in the area of fertility management:

  • All essential nutrients need to be in balance within the soil system.
  • These essential nutrients must be accessible in ade­quate concentration to the plants.
  • Crops must be able to efficiently recover these avail­able nutrients.

Nutrient balance and concentration is the simplest part of managing soil fertility. Assuring nutrient recovery is consider­ably more complex. The first three areas of management — soil aeration, soil water and soil decay — are keys to guaranteeing nutrient recovery.

Root growth and the uptake of nutrients are oxygen-con­suming processes. Soil aeration guarantees these two functions if water is in adequate supply. Air and water are also necessary to the release of nutrients through the decaying of crop residue.

These first three areas of management are controlled primar­ily through tillage and the activities of soil life. Tillage and soil life are both important and must complement each other. The permanence of soil structure or tilth can be maintained only through the continuous activity of soil life. When soil becomes biologically inactive, gravity begins to rule and tightens the soil.

In effect, the soil life serves as a dispersion machine by floc­culating the soil particles with the glues of microbial exudates to prevent gravity from pulling individual soil colloids together into massive structures.

Figure 25 (below) shows massive structures formed in biologically inactive soils. These structures are not friendly to plant or soil life.

clods of soil

Figure 26, on the other hand, shows the beautiful crumb-like structure which only active soil life can form.

good top soil structure

We emphasize that most tillage operations are in some degree detrimental to the soil system. Excessive tillage can over-aerate the soil, cause too much oxidation of humus and residue, disturb soil life activity, and give way to compaction and clod problems, all of which can become very yield limiting.

On the other hand, tillage can encourage soil life if it improves soil aeration, water and residue management. Most tillage programs do not complement these three areas, and the result is that biological activity is not sufficient to maintain good soil tilth on many farms.

Let us review the effect standard preplant spring tillage systems have on soil microbial activity. In spring, we can usu­ally observe our soil starting to develop a crumb-like structure, which starts at the surface. This structure is the result of micro­bial activity releasing exudates that structure the soil by group­ing the soil particles into crumb-like aggregates.

This granulation or crumbing of soil particles will continue its downward mellowing effect until something interferes with the soil life. A heavy, beating rain on unprotected soil can seal the surface, causing soil aeration problems that slow or even stop the microbial soil-mellowing action.

Standard tillage is the major culprit in stopping this desir­able biological process. Preplant spring tillage works soil to a depth of 4 to 6 inches. This mixes the upper, biologically active layer of soil with the lower, cold, wet and biologically inactive soil. This loosening and mixing almost certainly stops biologi­cal activity dead in its tracks.

Soil mixing also causes smearing, drying and the formation of clods that break the continuity of the soil biology, sending it into dormancy. Unless conditions turn favorable, the biological activity may not reestablish itself for the rest of the season, with the result being tight, dense soil that can only be aided by extensive tillage to loosen the soil or crush the clods.

Clods such as those shown in Figure 25 (above) are primarily topsoil material, the most productive soil on the farm. They can represent 2 to 4 inches of the topsoil, and as such, they are totally out of production.

Biological activity within the soil is the only way to main­tain permanence in the soil structure. Destroying the biological environment leads to permanently nonstructured, compacted soil. This situation will not be tolerated by those who under­stand gas diffusion and the importance of soil aeration. When done correctly, practices such as zone-tilling to eliminate preplant spring tillage will enhance the biological process.

It is essential that the reader recognize that the primary purpose of a well-planned tillage system is to complement soil aeration, soil water and soil life in such a way that we guarantee optimal crop response to soil fertility. This is a radically new way to view the purpose of tillage and add new meaning to our term, “tillage in transition.” The term implies a change of direction. We must know exactly where we are going, and our changes must be based upon knowledge, rather than trial and error or hearsay.

Want more? Buy this book from Acres U.S.A. here.

About Donald Schriefer

Donald Schriefer

Donald L. Schriefer passed from this life on July 30, 1998. He had spent more than five years battling acute leukemia, but he did not lie down and wait for death to come. He left this manuscript as a legacy to his lifelong friends — the farmers — knowing that those left behind would have it published.

One of America’s first “environmental agronomists,” he is best known for his consulting work on behalf of many of the country’s largest, most successful farmers. His innovation in tillage systems, foliar feeding of crops, and soil fertility management earned him the respect of both conventional and ecological farmers. He contributed frequently to various agricultural publications and was well known for conducting numerous seminars and farm programs annually. He has previously writ­ten two books, From the Soil Up and Tillage in Transition.

An Introduction to the Organic No-Till Farming Method

By Jeff Moyer

It is the hope and dream of many organic farmers to limit tillage, increase soil organic matter, save money, and improve soil structure on their farms. Organic no-till can fulfill all these goals.

Many organic farmers are accused of overtilling the soil. Tillage is used for pre-plant soil preparation, as a means of managing weeds, and as a method of incorporating fertilizers, crop residue, and soil amendments. Now, armed with new technologies and tools based on sound biological principles, organic producers can begin to reduce or even eliminate tillage from their system.

Organic no-till is both a technique and a tool to achieve farmer’s objectives of reducing tillage and improving soil organic matter. It is also a whole farm system. While there are many ways the system can be implemented, in its simplest form organic no-till includes the following elements:

  • annual or winter annual cover crops that are planted in the fall,
  • overwintered until mature in the spring, and then
  • killed with a special tool called a roller/crimper.
Jeff Moyer, Transitioning to Organic, from the 2015 Eco-Ag Conference & Trade Show. (1 hour, 3 minutes). Listen in as Moyer, the executive director of Rodale Institute, teaches a class on important details to know before you transition your operation to organic.

After the death of the cover crop, cash crops can be planted into the residue with a no-till planter, drill or transplanter. Whether you grow agronomic or horticultural crops, this system can work on your farm, and we’ll show you how to get started with this exciting new technology.

Farmer organic no-till farm
Organic no-till is a rotational tillage system that combines the best aspects of no-till while satisfying the requirements of the USDA organic regulations.

These techniques and tools can work equally well on both conventional (farms based on chemically based practices) and organic farms (farms that follow the USDA’s definition of organic).

Organic no-till is a rotational tillage system that combines the best aspects of no-till while satisfying the requirements of the USDA organic regulations. It is not necessarily a continuous no-till system but one that may include some tillage in rotation, especially to establish the cover crops. After cash crops are planted, no further tillage or cultivation is generally needed, and this greatly reduces the required field operations.

While organic farmers typically work the field several times just to get the crop in the ground, organic no-till farmers can get by with as few as two field operations: rolling the cover crop and planting the cash crop in one pass, and then harvesting the cash crop. By reducing the number of field operations, farmers can save on fuel and time — all the while building up their soil.

Cover crops are the cornerstone of weed management and soil building — so much so that they become as important as the cash crop.

Most organic farmers know something about cover cropping, but with organic no-till you’ll get a chance to sharpen your skills. If you are managing a chemically based operation you can still take advantage of these tools and use cover cropping on your farm. Winter annuals like rye and hairy vetch are common examples, but summer planted buckwheat, field peas, many small grains, and annual legumes are also a possibility. A later chapter on cover crops will tell you more about which cover crops can be killed by rolling and when.

Our rule of thumb is simple: if you can step on the plant and it dies, then you can kill it with a roller/crimper. This means that plants like alfalfa or perennial weeds are not good candidates for rolling.

Farmer no-till cover crop mulch
The author pulling back the killed cover crop to show no-till mulch in action with corn seedlings.

When seeded at the correct time during the fall, these cover crops will get started by developing an extensive root system and growing a small amount of vegetative matter. During the winter, the cover crops will either continue to grow slowly (in warmer climates) or essentially remain dormant (in the north).

There are several benefits to a winter cover crop, including erosion control, nutrient cycling, and microbial habitat in the root zone.

During spring, the cover crops jump to life and really put on biomass. Then they can be killed with the roller/crimper as they reach the peak of their life cycle.

With the winter annuals commonly used in the system, this corresponds to the period when they are entering their reproductive phase. For example, with winter rye, the correct time to roll the cover crop is when the rye is in “anthesis” or producing pollen. With hairy vetch, the vetch should be at least 75 percent in bloom, but 100 percent bloom is even better.

An annual crop typically allocates 20 to 30 percent of its resources toward the process of flowering and seed production. In addition, enzymatic changes at this time cause the plant to begin to senesce, or start the process of aging and breakdown prior to death. During this phase of the plant’s life cycle, it is much more vulnerable, and can be effectively killed by the roller/crimper.

No-till farm roller crimper
The Rodale Institute roller/crimper in action.

The roller/crimper is a specialized tool designed by John Brubaker and myself and tested at the Rodale Institute. It works by rolling the cover crop plants in one direction, crushing them, and crimping their stems.

The roller/crimper can be front mounted on a tractor, while a no-till planter, drill or transplanter brings up the rear, planting directly into the rolled cover crop. Or the roller can be pulled in a separate pass.

Since the system is based on biology and mechanics, it is scale neutral — suitable for use on either small or large farms. The roller/crimper can be pulled behind a tractor, a horse, or even by hand depending on the scale of the operation. While other tools, such as a stalk chopper, rolling harrows, and mowers have been used for this purpose; the roller/crimper has several advantages over other tools. It has been specially designed for organic no-till, and performs its function exceptionally well.

Provided that the cover crop is thick enough, the field will take care of itself for the rest of the season.

The mashed cover crops provide a mulch layer for the cash crop, both preventing the growth of weeds, but also breaking down gradually during the season to provide a long-term slow release of nutrients.

To achieve adequate weed control, the cover crop should be planted at a high rate and produce approximately 2.5 tons of dry matter per acre. For this reason, only certain kinds of cover crops, ones that yield a high amount of biomass, work well for the no-till system. It’s also important to select cover crops with a carbon to nitrogen ratio higher than 20:1. The higher the ratio, the more carbon, and the more slowly the crop will break down.

This will provide a consistent weed management barrier through the season. These topics will be explained in more detail further in this book.

After harvest, the killed cover crops can be disked under and the next round of cover crops is planted for the following season. Thus, the crop year begins in the fall with planning for the following year. For this reason, organic no-till requires considerable long-term planning.

Principles of Organic No-Till

Organic no-till rests on three fundamental principles:

  • soil biology powers the system;
  • cover crops are a source of fertility and weed management; and
  • tillage is limited, and best described as rotational tillage.

In both the goals and ideology, organic no-till is very similar to other kinds of organic farming.

These include soil building with organic matter and soil biology, managing weeds, insects and diseases through diverse and non-chemical means, and achieving general plant health through soil health and good management practices. However, organic no-till uses different methods to achieve those goals. Much more emphasis is placed on cover cropping, which replaces tillage and cultivation as a means of soil building and managing weeds.

Maximize Natural Soil Biology

In organic no-till, as with all types of organic agriculture, biology replaces chemistry. This means that organic farmers let the soil organisms do the work of facilitating nitrogen fixation, improving nutrient cycling, as well as enhancing soil structure and texture.

These soil organisms include macroorganisms like earthworms and as well as microorganisms like soil bacteria and fungi. Organic no-till goes one step further than the current technology offered in organic systems.

By providing nearly year-round cover and limiting tillage, the soil biology is given a chance to thrive and power the system that is the organic farm.

Chemistry, as used by conventional agriculture, has some fundamental problems. When we say chemistry we mean synthetic products such as man-made fertilizers and pesticides.

Conventional no-till is closely tied to herbicide use, since this is the primary means of weed control. Typically, as tillage is reduced herbicide management is increased in an attempt to control weeds. Although some surface residues are generated from no-till, they are not enough to provide consistent weed control.

This dependence on herbicides generates a host of problems, from resistant weeds to the destruction of beneficial insects.

Genetically modified crops (GMOs) are also commonly used in a conventional no-till system since the marriage of herbicide resistant crops and ag chemicals has been a consistent theme.

There are a number of concerns about GMOs — they may cause allergic reactions in sensitive individuals, they can cross pollinate with non-GMO crops, and there is an increased dependence on chemical herbicides and pesticides. GMOs also prevent farmers from saving their own seed since these technologies are all patented. None of these technologies are currently allowed under the USDA organic standards.

About the Author

Author Jeff Moyer
Jeff Moyer

Jeff Moyer has been working in the field of organic agriculture all of his adult life. Over the past 28 years he has been the farm manager/director for the prestigious Rodale Institute located in Southeastern Pennsylvania. Moyer’s interest in agriculture began while growing up on a small farm in Pennsylvania where his family grew and produced much of the food they consumed. Eventually, his desire to participate in the organic movement of the ’70s led him to the Rodale Institute, where he worked for 20 years on designing equipment specifically for the management of cover crops. He currently chairs the United States Department of Agriculture’s National Organic Standards Board and serves as an advisor on organic issues to the Secretary of Agriculture. Jeff is also a founding board member of Pennsylvania Certified Organic, a private non-profit certification agency. He serves (and has served) as a member of several other committees and boards as well. He is also a past president and current member of the Northeast Society of Agricultural Research Managers. Moyer also manages Sky Hollow Farm, a small farm of his own where he and his family have lived for over 30 years.

SOURCE: Organic No-Till Farming

Non-toxic Management Practices for Weeds

Charles Walters describes important farm management practices concerning soil health and the identification and non-toxic treatment of weeds.

By Charles Walters

For now, it seems appropriate to walk through farm management practices worthy of consideration. How they fit soils in any area and how they dovetail with crop systems projections becomes all important for the grower who wants to minimize the hazards of weeds so that he does not have to depend on the obscene presence of herbicides to control them.

Fall Tillage

Fall tillage has to be considered number one. It is the first thing a farmer should want to do, yet every fall when the crop is harvested, that bad weather always seems to arrive. Often the fall work does not get done. The farmer is too busy harvesting and he can’t get in there and do the tillage.

Moreover, most crops are harvested late because schoolbook technology has given us degenerated soils. We do not convert and use fertilizers, nitrogen and other fertility factors locked up in the soil to properly grow field-ripened crops.

Proper fertility management would see to it that harvest can take place a month earlier and thus permit time for that fall work. That is when compaction could be best removed, when trash could be mulched in. That is also the time when pH modifiers could be applied. That is when lime and other nutrients could be used to influence the quality and character of the soil’s pH, all in time to meld into the soil during fall and over winter.

It is this procedure that would make the soil come alive in spring and get the growing season underway so that crops can germinate a week or ten days earlier.

Fall tillage is an important key to weed management. It is certainly one way to diminish the chances for foxtail and grass type weeds. If fall tillage is used to put soil systems into ridges, those ridges will drain faster in spring. They will warm up a week to ten days earlier. They will have germinating capacity restored earlier and permit planting earlier so that the economic crop can get a head start on weeds.

Once the soil is conditioned, it won’t be necessary to turn the soil so much in spring. Obviously, every time the soil is turned, more weed seeds already in the soil are exposed to sunlight and warmth and other influences that wake them out of dormancy. Soil bedded in the fall, with pH modified so that the structure does not permit crusting when spring rains arrive, will permit rain to soak in faster, bringing air behind it. Such a soil will warm faster and therefore determine the hormone process that will take place. Good water and air entry into the soil will not likely set the stage for foxtail (image below), nut sedge, watergrass and other debilitating influences on the crop.

Foxtail can be avoided with practical weed management
Anhydrous ammonia is almost an insurance policy for its proliferation. Foxtail grows in organic matter soil where there is a surplus of humic acid. Although pH adjustment has been front burner stuff so far, the topic has to surface in any discussion of the foxtail weed problem.

When the cash crop is germinated under these conditions, that is when your little pigweeds and lambsquarters, your broadleaf weeds — which require a good quality available phosphate — hand off their message. They say the phosphate conversion is good and the fertility release system is more than adequate to grow a high-yielding crop.

Such broadleafs are easy to manage. When they germinate and achieve growth of an inch or less, and you tickle the soil before you insert the seed, they are easily killed off. As a consequence, the hormone process gains the upper hand for four to six weeks, a time frame that permits the crops to grow big enough to be cultivated.

Organic Materials in the Soil

Needless to say, the bio-grower has to depend on proper decay of organic materials in the soil. Root residue and crop stover are always present, and these have a direct bearing on how prolific weeds might grow. This means farmers, one and all, must learn how to manage decay of organic matter better.

As we incorporate it into the soil, preside over proper decay conditions by pH management and regulate the water either present or absent, we achieve plenty of air and good humid conditions that will allow organic material to decay properly and in the right direction to provide the steady supply of carbon dioxide necessary for a higher yield.

While adjustments are being made in the soil — soils are sometimes out of equilibrium for years — it is unrealistic to expect the situation will be corrected in a single season or a single month. We can speed the process with the application of properly composted manures. The point here is that there is a difference between quality of various composts, just as there is a difference between predigested manures and manures sheet composted in the soil itself.

Readers of Acres U.S.A. in general, and those who have enjoyed the short book, Pottenger’s Cats, will recall how that great scientist planted dwarf beans in beach sand at Monrovia, California, as part of an experiment. Cats had been raised on that beach sand. Some had been fed evaporated milk, others raw meat, still others meat that had been cooked to achieve near total enzyme-destroying potential and some had been fed on raw milk. Cats fed evaporated milk, cooked meat — dung going into the beach sand — produced a dilapidated, depressed crop of beans. Cats fed whole milk — their dung also going into the beach sand, produced a prolific and extended crop, the dwarf bean variety growing to the top of a six-foot-high cage. The quality of manures used in composting have a direct bearing on the performance of that compost.

Experience has taught all those who wish to see that the kind of compost Fletcher Sims of Canyon, Texas, introduces into the soil has many desirable fungal systems of bacteria and molds. These have the capacity to attack rhizome roots of quackgrass, Johnsongrass, and those type of roots so far under the top of the soil they cannot be reached with physical tools. Compost tells us that we have to set in motion an environment with antagonistic fungi that will attack the rhizomes when they are in a dormant phase as the season begins to close.

In late August and early September, the length of the day shortens. Everything starts to go into fall dormancy. If at that time we can apply a wholesome, properly composted material to the soil and have it working for thirty days before the soil freezes and becomes inactive, a lot of weed cleanup work takes place at that time. Compost will simply digest most of the dormant weed seeds, and in two or three years of this approach seeds are literally vacuumed up, like soil particles on the family room carpet.

The key is timing. When weeds go into dormancy, they are subject to decay. They can be turned into fresh humus, rather than a charge of gunpowder ready to explode. Quackgrass in particular responds to the compost treatment. With calcium-adjusted pH, compost will attack quackgrass roots and rot them out in one season. The same principle operates with deep-rooted rhizomes, Johnsongrass and thistles.

Quackgrass signals soil decay systems are poor
Quackgrass, sometimes called couchgrass. Agropyron repens is shown here (A); its spikelets (B); the ligule (C); and florets (D). Decay systems are at fault when this weed appears.

The simplest way to start a biological weed control program, then, is to adjust the pH. This affects the intake of water and makes it possible to manage water.

In the cornbelt, where rain often comes at the wrong time and where droughts frustrate the best of intentions, this management of water and its capillary return is front burner stuff. pH management directly relates to so many desirable things, there is justification for referring the reader to the several volumes of The Albrecht Papers for background insight.

Soil Management

Each weed has a direct bearing on the track record of the farm. Each reflects back to what the farmer has done correctly or incorrectly over the years. Too often — in this age of super mechanization — we have large fields with soft spots and hard textured soils. The farmer moves across one then over the next area because he feels impelled to farm big fields with big machinery. All the low soil is too wet, and so a pass through sets the stage for wild oats or foxtail in corn, or fall panicum.

Some soils get the wrong treatment simply because they, not the weeds, are in the wrong place. It may be that the eco-farmer will have to redesign the shape of his fields, or plant in strips so that similar types of soils can be planted at the same time, with due regard being given to the need for soils to dry out and warm up and drain properly. It might be better to wait a couple of weeks. A little delay is better than wet soil work which leaves no chance at all for a crop.

As far as weeds as related to insects, the great Professor Phil Callahan has given us a roadmap that cannot be ignored. He called it Tuning In To Nature, and in it he related how the energy in the infrared that is given off by a plant is the signal for insect invasion.

It stands to reason that a plant that is subclinically ill will give off a different wavelength than the one with balanced hormone and enzyme systems. That these signals match up with the signals of lower phylum plants is more than speculation.

While writing An Acres U.S.A. Primer, I often made field observations that supported Callahan. It became obvious that when farmers did certain things in the soil, the crop could endure the presence of insects because they seemed incapable of doing much damage. I didn’t know how the mechanism worked, at least not before the release of Tuning In To Nature.

Weeds are going to tell about the nutritional supply, and they therefore rate as a worthy laboratory for making judgments about the soil’s nutritional system. They can often reveal the nutrients that must be added to the foliage of the growing crop to react with the negative effects of stress. After all, all growing seasons have variable degrees of timing and stress. It is not only necessary to arrive with nutritional support in time, it is mandatory.

The many mansions in the house of weeds all have family histories. They tell more about gene splicing and DNA manipulation than all the journals of genetic engineering put together. And if we pay attention during class, weeds are our greatest teachers. To learn our lessons, we have only to get into the business of watching weeds grow.

Source: Weeds—Control Without Poison 

Tillage Types for Soybeans: Traditional, No-Till and Ridge-Till Methods

By Dr. Harold Willis

The tillage methods you use for soybeans should depend on your climate, soil type, slope, crop rotation, machinery and costs.

Traditional Soybean Tillage

Tillage is done for three reasons: to prepare a seedbed or improve-soil structure, to incorporate organic matter and fertilizers, and to control weeds. There are several commonly used tillage methods. The moldboard plow lifts and turns the soil, inverting the plow layer. This causes drastic disturbance in the soil ecosystem, but can be useful in heavy soils if done in the fall. Winter freezing and thawing may improve soil structure.

Chisel plows fracture the soil rather than turning it. Less energy is needed-to pull the plow, and the soil is disturbed less. Some plant residue is left on the surface, which is helpful for reducing erosion.

Discs cut and loosen soil and incorporate much of the plant residue, but they compact the soil beneath the blades.

Field cultivators and springtooth harrows dig and lift the upper layers of soil and do not compact lower soil. Little residue is incorporated.

Rotary hoes break up clods and crusts and leave a fine-particle layer.

Subsoilers and deep chisels are used to fracture subsoil and break up hard-pans, in an attempt to improve drainage and deep soil structure. Generally the effects are temporary, and without increasing soil humus, hard soil conditions will return.

In general, tillage on humus-poor, heavy soils causes deleterious effects, espe­cially if overdone. Soil structure is destroyed, organic matter disappears and ero­sion increases. Tillage operations should be kept to a minimum if soil is poor.

no-till soybean field
A no-till soybean field in Argentina.

No-till Soybean Farming

The above disadvantages of tillage in poor soils have led to the development and promotion of various reduced- and no-till systems. By using special planters that can operate in surface crop residue and by using high levels of herbicide for weed control, crops can be grown fairly successfully (except in northern climates on poorly drained clay soils).

While it is true that reduced-tillage systems do reduce erosion and save fuel, the requirements for high amounts of fertilizer and pesticides and the long-term tendency for deep soil to become depleted in oxygen and toxic are disadvantages. Soil-living pests and diseases often increase, and springtime soil temperatures may be cold.

All of these disadvantages of no-till could be eliminated and most of the advantages obtained if an adequate level of humus (up to 10 to 12%) is main­tained in the soil and if the use of materials toxic to soil organisms is reduced or eliminated (pesticides, some herbicides, high-salt and chlorine-containing fertilizers, over-use of raw manure). Humus and soil life create loose, non-crusting soil structure and break up hard subsoil and hardpans, improving drainage. Erosion is greatly reduced because humus holds soil particles in small clumps (aggregates).

Ridge Planting

A fairly new tillage method that works well in some cases for corn and soybeans is called ridge planting or ridge-till. Rows must be at least 30 inches apart to allow ridges and valleys to be built up (branching varieties of soybeans must be used). The crop is planted on top of the ridges, with crop residue left in the valleys. Earlier planting is possible because ridge tops warm up soon, and wind erosion is reduced. Ridges catch more snow in winter. Weeds can be cultivated out in the valleys and if necessary, in-row herbicide can be used. Ridges must be built up each year, and machinery must be compatible with the ridge widths.

Still don’t know? Try these studies to learn more about the practical results from no-till and tillage studies:

Rodale Institute study on No-Till

A Yield Comparison from No-Till & Till (Kansas State University)

Benefits of No-Till (Michigan State University)

Soybean Seeding Rates by Tillage (Ohio State University)

No-Till Versus Conventional Soybeans (University of Kentucky)

Source: How to Grow Super Soybeans