Drive around any rural area in the springtime and you’re likely to see freshly tilled fields being made ready for crops. Tillage is so basic to agriculture it’s a paradigm that is frequently not questioned. We can’t understand no-till systems and why they are advantageous until we put them in the context of tillage and the disadvantages that go along with it.
The Disadvantages of Tillage
Tillage is one of the most time, labor, and equipment-intensive tasks on the farm.
It’s easy to see that a lot of time and effort could be saved if tillage were eliminated. The problem has always been how to prepare the soil for planting without tillage?
“Tilling the soil is the equivalent of an earthquake, hurricane, tornado, and forest fire occurring simultaneously to the world of soil organisms.” What radical, tillage-hating group made such a strong statement? The USDA-NRCS, in a pamphlet entitled “Farming in the 21st Century: A Practical Approach to Soil Health.”
It goes on to say, “Physical soil disturbance, such as tillage with a plow, disk, or chisel plow, that results in bare or compacted soil is destructive and disruptive to soil microbes and creates a hostile, instead of hospitable, place for them to live and work. Simply stated, tillage is bad for the soil.”
Tilling Damages Organic Matter
Tillage results in two self-perpetuating cycles: it burns up soil organic matter (OM) necessitating the addition of more, and it stirs up weed seeds, necessitating yet more tillage to kill the weeds.
Conventional farming “solves” these two problems in a manner that is not sustainable. For depletion of organic matter, it treats the soil as a substrate for holding plants and disregards the depletion of OM. For weeds, it has herbicides.
Organic agriculture offers improvements over conventional bare tillage. Most notably, organic system plans mandate that cover crops be grown between cash crops in order to add some organic matter back to the soil and to keep the soil covered when it is prone to erosion (over the winter, for example).
Soil has three properties that we are most interested in agriculturally: the physical, the biological, and the chemical. Tillage is bad for all three of them.
On the physical side, the action of tilling crushes the soil structure, making soil more likely to erode and less likely to absorb water efficiently. On the biological side, the action of tilling kills many of the organisms that live in the soil. Tillage breaks apart soil fungi and the aggregates they make that help soil resist erosion and promote water infiltration. Over time, this promotes a soil environment with more bacteria and less fungi.
And on the chemical side, accelerating the oxidization of organic matter promotes a short-term release of fertility, at the expense of the long-term reserves in the soil. Furthermore, the destruction of soil organic matter releases carbon that has been sequestered in the soil into the atmosphere as carbon dioxide.
In addition to the negative effects on the soil, tillage also wastes a lot of time and energy. On my farm, I’ve often thought, “If we didn’t have to spend all this time and energy tilling, we’d save a lot of time and energy.”
Tillage ties up a lot of money, in the form of fuel, labor, and equipment. It also ties up a lot of time, both in the sense of the time that it takes to do the tillage, but also in the sense that other farm operations may be delayed due to tillage. For example, tillage can’t be done when
it’s too wet or too dry, so farmers often find themselves waiting for the soil to dry out in the springtime to till, when the temperature is otherwise adequate to plant. If there was a cover crop on the ground before tillage, then you have to wait at least an additional two weeks for it to break down after tilling before planting.
No-till trades tillage for other methods of field preparation that are less complex, strenuous, and time-consuming. It is a less invasive, more efficient, and more profitable field prep process that grows healthy soil in order to grow healthy crops.
According to a USDA fact sheet, “A simple definition of soil health is the capacity of a soil to function. How well is your soil functioning to infiltrate water and cycle nutrients to support growing plants?”
The two best-understood areas of the soil are its physical and chemical properties. It has long been known that the physical condition and chemistry of the soil have a lot to do with the success or failure of crops. Now we know that the biology is very important too, but we still have a lot to learn about the biology of the soil.
Maybe it’s because soil biology was not thought important that conventional systems were designed to operate in spite of whether the soil was healthy or not. Tillage implements crush the soil into plantable submission, chemicals kill anything that might compete with the crop, and chemical fertilizers replace the fertility that was either lost from the soil or was no longer being cycled efficiently by biology. The cumulative effects of these practices are erosion, loss of fertility, and dead, nonfunctioning soil.
