(A version of this article appeared in the Nov. 2016 edition of Ripples, an internal newsletter of The Center at Donaldson)
What do you call the stuff underneath your feet? We often call it “dirt,” usually a negative term. We may dig up “dirt” on other people. Our clothes get “dirty.” But it’s not an accurate term. What we really mean is soil.
Soil is not some dead brown crust. It’s alive, and without it, we wouldn’t be. It’s more like a raucous party, or a battlefield, or a city: A single pinch of soil contains millions of bacteria representing thousands of species, not to mention all the nematodes, springtails, rotifers, mites, and tardigrades. (be thankful your parents didn’t give its name or looks!). These are all interacting with, chomping on, and moving around various nutrients, minerals, fungi, and roots of living plants. Soil also stores water, anchors plants, and changes the Earth’s atmosphere.
But despite having a lot to show off, soil is shy. It “wants” to stay covered up and keep its beauty under a clock of vegetation. As an ecological default, natural systems trend toward perennials, plants which persist in the soil for years at a time.
Our challenge is that our major agricultural crops are annuals, which we plant into a living community primed for perennial associations. We plant seeds in May, keep the weeds down, then harvest everything in October. But from November to April, the soil surface bare. The tiny species that keep the soil healthy begin to starve for lack of solar-powered plant roots injecting food into the system. Nutrients begin to leech out of the soil and into waterways. We’re farming naked!
Enter cover crops, which are simply annual plants that can share soil space with our main agricultural crops. Planted in late summer or fall, they thrive in the cool wet months when corn or soybeans cannot grow. Some species even withstand frost and persist into the spring. In the spring, any remaining cover crops are then terminated (killed by tillage or herbicide) to allow space for planting of the main crop.
Research has shown several benefits of certain cover crop rotations: reduced compaction, erosion, and fertilizer inputs; increased soil moisture and soil carbon; and feeding the microcommunities that keep soil alive. Aesthetically, a green, textured field is a great improvement over an endless blanket of brown. Some flowering cover crops can even benefit pollinators. Indiana has seen a 500% increase in cover crop usage since 2011, now covering one million acres, about 10% of our corn and soy fields.
This fall, we are planting cereal rye as a cover crop in a field just east of the farm, on 9C road. This planting is made possible with funding from Clean Water Indiana, provided through the Marshall County Soil and Water Conservation District.
Since the soil feels a little shy about its glory, we’ll try keep it covered with living plants. If you see our hard-working farmers, be sure to thank them for not farming naked!