Abstract
Interseeding cover crop by aircraft into standing corn to provide for fall/winter grazing is a practice gaining interest in southcentral Idaho based on grower input. University of Idaho Extension faculty cooperating with a dairy producer studied the efficacy and best timing to plant a cover crop into corn. The questions guiding the research were: 1) what is the correct crop stage to interseed cover crop into standing corn to provide late-season grazing; and 2) will interseeding cover crop reduce corn silage yield? The study was replicated in 2017, and 2018 with the only researcher-controlled variable being planting date. Results indicate there was no statistical difference in yield between planting date treatments in 2017 (P=0.43), but there was a statistical difference in 2018 (P=0.03). The cover crop was clipped and weighed in October of each year to determine available forage. The results show that planting the cover crop at approximately corn stage V6 gives the best opportunity for establishment before the corn closes the canopy.