A trend has recently cropped up in the agricultural industry, and this one’s a keeper. Cover crops have overtaken the practices of heavy irrigation and chemical fertilizers to revitalize soil after the seven months between harvest and planting each year.
According to the 2017 agricultural census, the percent of U.S. cropland planted with cover crops increased by 50 percent between 2012 and 2017, from just over 10 million acres to more than 15 million.
Planting cover crops is an accessible agricultural strategy for improving soil health and water retention, nutrient cycling, and preventing weeds and nitrogen pollution in water and erosion. Some science even shows that cover crops can improve the ability of soils to store carbon.
Here we look at some of these benefits in more detail:
Soil Health and Fertility
Cover crops, particularly those with nitrogen-fixing abilities such as legumes and radishes create a continual loop of nutrient and nitrogen cycling that rivals compost and manure.
Improved Soil Texture
Plants like daikon radish have roots that break up compacted soil, while other plants like annual rye have fibrous roots that hold together loose soils. Selecting crops based on the characteristics and benefits of their roots will improve soil texture, which is as important as its fertility.
Cover crops protect the soil from drying out and being carried off by wind. They hold the soil in place during rain, while also helping to manage absorption of the rainfall and maintain pore space (avoiding compaction).
Both below and above ground growth of cover crops add organic matter to the soil, thereby increasing moisture retention and improving soil aggregation.
Prevention of Weeds
Cover crops, which are typically grown densely, fill the space weeds would otherwise invade, and block sunlight from weed seeds, so that they don’t have a fighting chance.
As cover crops, otherwise known as “green manure,” are on the rise in U.S. agriculture, the state of Maryland takes the cake: Politico reported that Maryland farmers planted cover crops on more than 43 percent of the commodity corn, soybeans, and cotton acres in 2017, and numbers reported by the state department of agriculture since then have been upwards of 50 percent. Other Northeast states report more than 30 percent of cropland in cover crops, but many Midwest states come in at under five percent, while only about four percent of the nation’s total cropland is planted with cover crops. The next census won’t be done until 2022, but the practice is spreading. Whether farms are large or small, that's less fertilizer used, which is a good thing for the environment.