Nursing the Soil Back to Life

By JIM VAN DER POL

The first two principles of soil health-cover on the soil and reducing disturbance (tillage) are about keeping soil organic matter in place. The final three principles are about building it back up. And all three of those-diversity on the land, living roots in the soil, and animal impact-are related to the matter of annual plants vs perennial ones.

How did we get here? It seems to me that modern agriculture has been carelessly destructive of soil for as long as I have been aware, certainly for as long as it has been “modern.” Perhaps it is a century and more now, roughly corresponding to our increasing dependence on petroleum for fuel and fertility. I well remember in my earlier years seeing a regular series of articles in the farm press as to the usefulness of decreasing organic matter levels in the soil, the argument being that the decrease made the soil more “workable.” What was meant was that the soil held less water, and thus was available to be planted a day or so sooner, extending the season, always a premier issue with farmers. Lately now, in the last several decades, there has been a mind changing in academic agriculture about soil organic matter due at least in part to increasing concerns about runoff and erosion. From urging the slowing of soil loss, the academics began to talk of stabilizing it and finally, just lately, exploring the possibility of increasing it very slowly and gradually. This is somewhat analogous to the public mind changing about fats in the diet.

Organic matter levels in the soil are related to soil life. It is a mutually beneficial relationship in which an increase in one encourages building up of the other. Organic matter and soil life build soil health. A healthy population of microbes and fungi, as well as small insects and arthropods existing in symbiosis with the plants will produce a healthy soil. These increase organic matter, processing it from plant residue and animal manure and urine. Organic matter reduces compaction and puddling by improving soil structure, retaining and storing rainfall. Soil health has to do with how water cycles, how energy flows between soil and plants (symbiosis), and the carbon cycle. It is healthy soil that can reduce torrential rains by retaining rainfall, thus reducing the runoff that accelerates the water cycle. It can also fix atmospheric carbon into a stable form in the soil.

Anyone concerned about “climate change” would respond to the idea of sequestering carbon in the soil. But we must be careful. A focus on just this aspect of the soil community and its related cycles will not work. This is not about adoption of technology. It is rather about our management of the various places we live and work toward the rebuilding of soil health. It has been stated by soil scientists that there is, even in our current situation of depleted soil organic matter, more carbon in the soil than in all the plants on earth and the atmosphere. If this is so, the possibility certainly exists to help the soil accelerate the carbon cycle, by which carbon moves from the atmosphere to the soil. How?

One change available to us is to move from an annual agriculture toward a more perennial one. And I would have to say that my 40-plus years of farming this rural place has shown me that this kind of change has a tremendous impact on the land. I knew it before I knew much about the particulars of how it happens. I saw the reduced runoff, the reduced compaction, the presence of growing green things year around — yes even here in the savage winters of western Minnesota — and the increasing fertility and productivity of the land I had planted in perennials before I really began to understand about the importance of soil life.

Do this. Go to the library, or to the internet and find charts that show something of root complexity and development. Check corn and soybeans, which are the basis of our annual agriculture. Then also look at prairie grasses such as big bluestem, a warm season native perennial grass. Check out intermediate wheatgrass, a cool season perennial as well. Notice how these perennial plants show root systems that are not only very much thicker and more complex, but also very much deeper. They will grow to a depth of more than eight feet while corn and soybeans do not go much beyond two. Now imagine management to help the carbon cycle, as well as the energy and water cycles operate at that depth. Visualize the changes we could see in the climate and the land.

We know some of this. It is not all guesswork. We know that a planned grazing use incorporating a variety of species will build organic matter in the soil. Each time the animals graze the sward down, the plants slough off a comparable volume of root mass. This plant material is the building block upon which a healthy soil can act, increasing organic matter-and thus carbon-in the soil. The plant regrows, building in more carbon from the air and the soil, and the process starts again, somewhat like a pump. If the plants being grazed are deep rooted grasses with a large volume of root mass, this organic matter is being built from the top of the soil down as far as the roots go. And this is why it is easier to rebuild soil organic matter and sequester carbon with a planned grazing practice than with annual corn or soybean cropping. The perennial plants being used are superior for the purpose, they root a heavy volume at a deeper level and there are usually four to six grazing events each grazing season, compared to a single residue producing harvest for corn or soybeans. And there is little or no tillage, which knocks back much of whatever progress in building organic matter that has been made even by the most careful of farmers.

New on the scene is Kernza, bred by the Land Institute in Kansas and being developed by the University of Minnesota among others. It is a perennial wheat developed from intermediate wheatgrass. This crop can be both grazed and harvested for the grain. There are now several restaurants and bakeries in the Twin Cities working with the flour. This is exciting indeed. It gives us another avenue for farming using perennial plants.

Jim Van Der Pol farms near Kerkhoven, Minn. A collection of his columns, Conversations with the Land, was published by No Bull Press (nobullpressonline.com).

From The Progressive Populist, March 1, 2019

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