(Vicia villosa Roth)
(also known as Winter Vetch)
Hairy Vetch is an excellent producer of residue and also nitrogen. It delivers high amounts of mineralized nitrogen that is readily available for the following cash crop. When used in a cropping rotation with cereal rye, soil moisture is actually greater than the soil in just a regular no-till or straight cereal rye cover crop field. With hairy vetch having vines that grow up to twelve feet, it quickly smoothers weeds, however with a very low carbon to nitrogen ratio, the residue is very quick to decompose. It is important that the farm manager is ready to take on the task of planting the cash crop into the hairy vetch residue, because it does have a tendency to wrap if given the opportunity. So minor equipment adjustments may be needed.Hairy vetch is a winter annual legume that has been used as a cover crop for years, primarily as a green manure crop for its nitrogen fixation ability. Its primary use has been in the Southern states due to the extended growing season. Vetch produces limited root growth compared to other legumes and grasses.
Hairy vetch requires a specific innoculum to efficiently fix nitrogen. Very little nitrogen fixation occurs below 40 degrees F, and since it takes three weeks for nodulation to develop, very little nitrogen is fixed in the fall in the upper Midwest. For maximum nitrogen production, the spring kill date needs to be delayed as long as possible, which in the upper Midwest is usually past the optimum planting date for corn. If nitrogen production is the primary objective, harvesting forage should be avoided since most of the nitrogen is in the top growth.
Cahaba vetch was bred to be an excellent forage in the east and southern parts of the US during the winter. In the transition zone it has shown good winter hardiness. It is produced and marketed through Saddle Butte Ag.
Caution: Hairy vetch can have 15-30% hard seed which may germinate for several years after planting. Avoid using ahead of wheat. Never let it go to seed in cropping fields. Hairy vetch is a host to soybean cyst nematode.