[Excerpt] The Organic No-Till Farming Revolution: The Disadvantages of Tillage
Andrew Mefferd, editor of Growing for Market and author of The Greenhouse and Hoophouse Grower’s Handbook (which we cannot recommend enough for protected culture growers), just published The Organic No-Till Farming Revolution. Take a listen to the NTMG podcast where he explains the impetus of his writing the book, his past experiences in no-till systems, and where no-till could have, and how he implements it in his high-tunnel production.
If his book is on your wishlist (or your cart already, use discount code NOTILL to get 35% off), and you didn’t win our giveaway, here’s an excerpt from chapter two about how the disadvantages of traditional tillage. For an overview, you can check our blurb for a better idea of the structure of the book itself. Get your copy from New Society Publishers today.
The Following is an excerpt from The Organic No-Till Farming Revolution: High Production Methods for Small-Scale Farmers, by Andrew Mefferd. Big thanks to New Society Publishers for giving us permission to run this excerpt. Farm publishers are the best…
The Disadvantages of Tillage by Andrew Mefferd
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."
Tillage results in two self-perpetuating cycles: it burns up soil 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.
Once again, organic systems do better by incorporating cover crops to make up for organic matter destroyed through tillage, and at least by not using all those chemicals. But I have come to think of most tillage systems as having built-in remedies to try and deal with the destruction that they cause.
Conventional systems try to get around degraded soil biology and physics by using chemicals to keep plants productive. Organic tillage based systems try to promote the biology in spite of the damage they are doing to the soil. Over the course of doing the interviews for this book, I've come to think of no-till systems as operating because of soil biology, not in spite of it.
No-till systems have advantages when it comes to promoting a healthy soil system. For one thing, they're not burning up the soil OM through tillage in the first place, so they don't have to do the one step forwards/one step backwards dance of tilling and then adding more OM to make up for the tillage you just did. So we can say they make it easier to raise the percentage of OM on your soil test.
In addition to sequestering carbon, increasing OM improves all three aspects of the soil. Higher OM increases the tilth of the soil (physical) and the life in the soil (biological), which will in turn improve the availability of nutrients in the soil (chemical).
Over the course of these interviews I've come to see what we used to regard as the least important element of healthy soil as the most important. Let's go back to our simple definition of soil health as the capacity of a soil to function. In a healthy soil the biology can improve the physical and chemical properties. Thus the organic adage to “feed the soil to feed the crop.” In no-till systems, I've seen how the biology is promoted specifically to make the soil texture and chemistry good for growing crops. Good biology builds good soil texture and chemistry.
In conventional systems, the opposite is true. Chemistry is used to make up for poor soil biology, texture, and chemistry. I think some of the systems in this book make the almost perfect "closed loop" system a lot of organic growers are looking for. Four Winds Farm, for example, has been using their system for two decades. They make their own compost, and over time the OM level in their soil has grown high enough that, even though the compost is not particularly high in fertility (by density or fertilizer standards), enough is being made available by biology to feed the plants.
More recently we've begun to understand the importance of biology—that it helps cycle nutrients in the soil and develop the aggregation that prevents soil from eroding. But soil biology is an area where we still have a lot to learn.
Let's go back to our definition of soil health as the capacity of a soil to function, so unhealthy soils are not very functional and healthy soils are highly functional. What chemical agriculture does is make unhealthy, low-functioning soils grow plants with quick hits of chemicals. Which is why conventional agriculture is compared to drug addiction-you're constantly adding more chemicals to make up for the damage of the previous chemicals, and constantly tilling (or spraying) to kill the weeds whose seeds you churned up the last time you tilled. Tilling more to make up for tilling. Spraying more to make up for spraying.
We need to start thinking of the health of the soil just like we think of the health of a forest, a field, a lake, or even a human community. These all can be self-sustaining ecosystems, with producers, predators, prey, and organisms that sustain them from season to season. In natural systems, or naturally managed agricultural systems, the soil can function as a self-sustaining community. But with frequent tillage, introducing the effects of “an earthquake, hurricane, tornado, and forest fire occurring simultaneously" on the soil ecosystem has the same effects such a cataclysm would have on a human community; not everything dies, but the larger organisms and fungi are disproportionately vulnerable when the physical environment of the soil is destroyed.
Repeated tillage has the same effect on the soil that repeated cataclysms would have on a human community; it throws the soil community into a cycle of constantly being destroyed and rebuilt, favoring the bacteria that survive to feed on those killed by tillage.