COVER CROPS IN A WHOLE FARM SYSTEM
The Benefits of Cover Crops
by Lynda Prim
Cover crops are plants grown specifically for their soil-enhancing qualities. Many farm crops such as clover, vetch, field peas, oats, buckwheat, winter wheat, and winter rye can be soil rejuvenators. They also function to protect areas of the soil between plantings and build soil fertility as living mulches or turned in as green manure. Legume cover crops, such as peas, clovers, cowpeas, fava beans, and vetch, store nitrogen for future use by other plants.
The presence of cover crops on the landscape can increase nutrient capture and lower soil erosion, both of which can improve water quality. In annual row-cropping systems where biomass is being removed by annual harvest cover crops have been found to have a positive impact on soil quality by helping to offset the carbon and nutrient losses. A self-seeded cover crop system is a technique that can minimize competition with row crops, save the farmer time and money, while taking advantage of the effectiveness of self-seeding for plant vigor.
A crop rotation system with grass that includes other suitable plant associations improves the soil by mobilizing and, at the same time, continuously renewing its biotic potential. Cover cropping and crop rotations together are organic management practices that can help to restore biological diversity in the landscape by providing plant diversity and habitat for beneficial insects in the field and garden while protecting the soil and building its fertility. Cover cropping in a crop rotation system allows for growing annual vegetable crops while replacing the nutrients removed by the cultivars without the use of off-farm inputs. Cover crops can also supply rotational grazing for small-scale livestock. For this reason, an organic farm or garden can become a habitat for all the species living in the system — from cultivated and wild crops, to livestock, to beneficial and predator insects, to microbial life in the soil. In this context, the farmer/gardener maintains and manages biological diversity. The crop rotation contributes to the management of diversity by moving the cover crops in the field or garden through time and space as needed.