Assistant Professor OSU-Extension Putnam County

This article is adapted from a new draft fact sheet on the “Benefits of Cover Crops” written by James Hoorman.
Cover crops protect the soil from erosion due to wind and water. Live plants provide the energy for soil microbes to recycle and store nutrients to build soil carbon and organic matter. They improve soil structure which improves water infiltration and water holding capacity. Cover crops may also reduce weed, insect, and soil disease pressures by adding diversity. Live plants also provide ecological services like purifying and cleaning air and water.

Soil erosion and sedimentation are major agricultural problems worldwide. According to Dr. David Montgomery (2012), even if farmers lose soil at the USDA-NRCS acceptable rate of four to five tons/acre/year, they will lose approximately one inch of top soil every 60 years. Montgomery says we are losing 0.5 percent of our arable agricultural soils every year worldwide due to soil erosion and it takes almost 500 years to replenish one inch of topsoil. Cover crops protect the soil by slowing down the wind at ground level. Blowing snow and dirt, also called “SNIRT,” is a common problem on bare or fallow soils. The reduction in sedimentation from water and wind erosion is a huge soil conservation benefit of cover crops (Hoorman, 2008).

Plants and microorganisms are critical in recycling soil carbon, nitrogen, phosphorus, sulfur, and micronutrients. Carbon ties up and stores major nutrients (water, N, P, S) and micronutrients (zinc, boron, copper). A recent study at Piketon, Ohio shows that 65-70 percent of the soil’s carbon originates from plant roots (Aziz PhD thesis, 2011). The soils in Illinois and Iowa are productive because they are high in soil organic matter. Carbon is the key to improving soil productivity because carbon ties up plant nutrients and still makes them plant available.