CONSERVE WYOMING’S SOILS: Farmers Harness Benefits from Cover Crops
July 3, 2013
By James Bauchert
acting state soil scientist
Bauchert is a soil scientist with USDA’s Natural Resources Conservation Service. He works in the agency’s Casper, Wy. state office.
A growing number of farmers in Wyoming have “discovered the cover”—and for some very good reasons. By “cover,” I’m talking about cover crops, which are plants established when cash crops are not being grown.
Cover crops are planted because of their excellent benefits, including improving the health and function of soil. This leads to better nutrient cycling, improved water infiltration and more consistent yields over time. Cover crops also suppress weeds, prevent erosion, control diseases and pests as well as help pollinators.
Farmers not familiar with how mixtures of cover crops work together might ask, “Why would I want to plant a cover crop that uses up all my water?” But using diverse annual cropping rotations and cover crop combinations increases soil organic matter. And for each 1 percent in organic matter, there is a 25 percent increase in water holding capacity and up to 30 pounds an acre more of available nitrogen.
While cover crops use some water in the soil profile to grow, they simultaneously improve the soil structure by building soil aggregates, providing armor for the soil surface, and recharging the water in the soil profile though increased infiltration.
About 600 farmers surveyed in 2012 on the impact of drought reported an average increase of 14 bushels of corn per acre and five bushels more of soybeans per acre where they had a cover crop as compared with fields without cover crops.
Planting cover crops is one of several key steps that farmers can take to improve soil health. The other two are rotating crops, including cover crops that are planted, and not tilling..
When a variety of cover crops are planted, especially when 10-12 plant species are planted, they increase the soil biology and speed soil health improvements. The more diversity you have, the more plant balance you have above ground, the better soil biology balance you have below ground. Plus, cover crops can help reduce compaction without deep tillage.
When only one cover crop species is planted, the single crop – or monoculture – will struggle in a drought or when facing pests. Many farmers are working with USDA’s Natural Resources Conservation Service to choose the right mix of cover crop seeds – or “cocktail” – for their farm.
If you farm or are interested in farming, visit your local NRCS field office for help on choosing the right conservation efforts for your land.