Cover crop and green manure
Hairy vetch is a much appreciated legume as a cover crop and green manure. Sown during late summer or mid-autumn, it rapidly provides cover and large amounts of N to the soil. Hairy vetch provides sufficient N for many vegetable crops, partially replaces the need for N fertilizer for maize and cotton, thereby increasing yield and N efficiency of the cash crop. Root development during winter is beneficial to soil structure, as it increases soil capillarity while reducing lixiviation and compaction. Hairy vetch improves biological activity in the soil. It is a P scavenger and reduces excess P in the soil (SARE, 2008).
Wildlife habitat
Hairy vetch is a very good source of pollen and nectar for honey bees, which forage readily on its flowers (Weaver, 1965).
Weed controller
Hairy vetch readily resumes its growth during spring and, combined with a tendency to allelopathy, the stand smothers spring weeds efficiently (SARE, 2008). A mulch made from rye, crimson clover (Trifolium incarnatum) and hairy vetch can control weeds for between 6 and 8 weeks (SARE, 2008).