Introduction

Six treatments of hairy vetch and rye cover crops were planted at several different rates Aug. 24, 2005 in a randomized complete block design consisting of four replications. Three of these treatments were of vetch alone at 30 lb/A and three were a mix of vetch (25 lb/A) and rye (2 bu/A). Rye alone was planted for three additional treatments Sept. 15 at 2.5 bu/A.

Methods
All treatments were rolled/crimped (R/C) June 5, 2006 and were seeded with food-grade S2020 variety soybeans at 180,000 seeds/A. One of the vetch treatments was R/C twice, once May 25 and again June 2. All other treatments were R/C June 2. Heavier than anticipated mulch and poor seed-to-soil contact resulted in two-thirds of the treatments being replanted to soybeans June 15. To evaluate the replanting, the remaining one-third of the treatments were not replanted.

results
Soybeans were harvested Oct. 15. Replanted plots did not yield significantly different from similar treatments that were not replanted. The lowest-yielding plots were of vetch only, averaging 23 bu/A. There was a significantly higher yield for rye only treatments (36.3 bu/A) as compared to the vetch only treatments. The vetch only treatments had the lowest soybean yields and had the highest fall weed biomass. Rye plus vetch plots yielded an average of 31.56 bu/A.

The research using the cover crops R/C for this year demonstrated that replanting soybeans into an existing soybean stand can increase soybean populations, but it did not show the R/C system to significantly increase soybean yield.