Hairy Vetch Nitrogen Contribution in Cover Crop Situation: The Central Sands area of Wisconsin has low organic matte soil that are 1.0 % or less. With the higher nitrogen prices this trial was done to measure the nitrogen contribution of hairy vetch seed with triticale in the fall. This trial was done to measure the nitrogen contribution of hairy vetch when seeded with triticale and harvested as hay.
Seeding Date: September 5, 2007
Seeding Rate: On 1/2 of the field we seeded 15 lbs of hairy vetch and 50 lbs of triticale per acre. On the remaining 1/2 we seeded only 50 lbs of triticale with no hairy vetch.
Harvest Date of Cover Crop: June 12, 2008 with 2.1 tons of dry matter per acre removed from the vetch and triticale, 1.6 tons per acre from the triticale only portion of the field.
Fertilization: On the triticale only portion of the field we applied the following: 33% no fertilizer, 33% 40 units of N, 33% 60 units N
On June 15, 2008 the field was seeded with a no till drill and 18 lbs of hybrid pearl millet was seeded into the existing stubble. The pearl millet was harvested as hay on August 20, 2008 and the amount of dry matter was measured on each treatment.
Table 1.Hairy Vetch N Contribution
Summary: From this trial it appears the hairy vetch is contributing 45-50 units of nitrogen to the pearl millet crop. The hairy vetch also increased the amount of forage harvested as hay in June by 1000 lbs per acre.
Economic considerations: Cost of hairy vetch seed @ $2.00 per lb or $30 per acre. Increased hay yield of 1000 lbs at $70 per ton returns $35 per acre and the 45 units of N at $.40 per lb of N adds an additional $18 per acre for a total return of $53. Based on these values the addition of hairy vetch to this fall seeded triticale crop is $23 per acre.