Cover crops, which are normally added to the crop rotation between two basic or forage crops, provide lively, seasonal ground cover with a variety of farm benefits, such as greater soil moisture capacity, better nutrient cycling and weed suppression. Cover crops are an integral part of organic no-till tillage. They help return nutrients to the soil and, when rolled up with the roller crimper, create a mulch that eliminates weeds. Plant cover crops in organic agriculture to provide nitrogen, control weeds and improve soil health.
In organic direct tillage agriculture, use a crimper to kill the cover crop and leave the mulch on the soil surface to conserve water. Or, incorporate the cover crop into the ground (sometimes called green manure) before planting the main crop. Cover crops are known to add organic matter to soils by incorporating them back into soils or by decomposing their root mass. Therefore, their inclusion can help producers maintain the productivity of their land in the long term.
Nevada's native soils have less than 1 percent organic matter, resulting in poor soil structure and lower water and nutrient retention capacity. Therefore, to improve soil quality, farmers should focus on increasing the organic matter content of soils. Increasingly, farmers and even urban and backyard gardeners are realizing that cover crops are critical to their operations and gardens. Whether you add cover crops to your current rotations or completely renew your agricultural system, you must devote as much planning and attention to your cover crops as to your cash crops.
The Rodale Institute is growing the organic movement through research, farmer training and consumer education. Soil erosion due to these forces (wind and water) causes the loss of soil particles, such as clay and organic matter, which are very important for maintaining soil fertility. Cover crops—plants that are grown primarily to promote the successful growth of other future crops—help combat soil erosion, improve soil health, eliminate weeds, control pests and diseases, increase biodiversity, and can bring many other benefits to your farm or garden, including greater profitability. Cover crops also keep something green and growing all year round, helping farmers to capture more carbon to combat greenhouse gas emissions.
For more information, read Crop Rotation on Organic Farms and the Profitable Management of Cover Crops, see the crop rotations page in this theme room and consult local experts. According to an analysis of yield data collected in a national cover crop survey, farmers can expect a 3% increase in their corn yield and a 4.9% increase in soybean yields after five consecutive years of using cover crops. Legumes also help prevent erosion, help beneficial insects and pollinators, and can increase the amount of organic matter in the soil, although not as much as grasses. NRCS provides technical and financial assistance to help farmers plant cover crops through the Environmental Quality Incentive Program.
Also remember that there probably isn't a single cover crop that's right for your farm (see Cocktails or Blends, below). Cover crops also help to quell weeds, control pests and diseases, improve water availability and increase biodiversity on the farm. Cover crops have also been shown to increase crop yields, break a plow, add organic matter to the soil, improve crop diversity on farms, and attract pollinators. Find examples of farmers using cover crops to combat insect pests and weeds in the Pest Management section of this theme room.
The incorporation of cover crops into soils helps to increase organic matter (OM) in the soil, thus improving the capacity of soil to retain water and nutrients. Non-leguminous plants are very useful for collecting nutrients, controlling erosion, eliminating weeds and producing large amounts of waste that add organic matter to the soil. .