Cover Crops
Cover crops have been in use for longer than you might have imagined. Ancient Romans knew the value of cover crops. A former legionary turned farmer, Lucius Columella, realized how important legumes such as lupine, black medic and vetch were to productive estates. He wished landowners, no matter how large or small, paid close attention to their soil.
Farmers around the world grow cover crops to protect the soil and increase crop yields; it adds fertility to the soil without chemical fertilizers. It can be left on the surface as mulch or tilled while it is still green into the soil, becoming a green manure. Farmers have used this technique for centuries. Green manures are crops that are grown not to be eaten by you, but to be turned into the soil and consumed by earthworms, insects and microbes.
Cover crops are an excellent tool for home vegetable gardeners as well, regardless of garden size, and provide many benefits:
soil erosion – the roots stabilize the root zone or surface of the soil, reducing the risk of erosion from wind and rain; the leaves and stems of the cover crop also decrease soil erosion by reducing the impact of rain and potential runoff.
soil compaction – the root systems can be used to combat both shallow and deep compaction.
soil organic matter – cover crop residues increase soil organic matter, providing numerous benefits to the soil and successive crops; increasing organic matter improves soil structure, soil water holding capacity and infiltration, and soil aggregate stability; decaying plant material contributes nutrients back to the soil to be used by future crops.
weed suppression – cover crops can provide an incremental benefit of weed control by out-competing weeds for light, water and nutrients.
disease and pest management – according to the Virginia Cooperative Extension, many articles have been published recently about cover crops being another tool for use in disease and pest management; particular members of the brassica family, certain mustards, and rapeseed varieties help control soil-borne pathogens such as root knot nematodes and verticillium wilt.
low maintenance – cover crops require very little maintenance, and additional nutrients are seldom needed to support them since cover crops scavenge nutrients already present in the soil, and may even “fix” additional nitrogen from the atmosphere.
Besides cover crops, gardeners can also improve the soil by adding compost or manures (when available) or other organic materials such as leaves, straw or grass clippings. Earthworms, bacteria, fungi, nematodes and other forms of life utilize the organic matter to build a healthy soil.
Source: Cornell Cooperative
