Interseeding Cover Crops in Corn: Impacts on Corn Yield and Cover Crop Biomass Production in the Mid Atlantic.

Cover crops have many advantages in cropping systems but are often difficult to establish following full season corn or soybeans.  Interseeding cover crops at the V5 to V7 stage is one opportunity to establish cover crops in these situations.  One issue is the impact of the interseeded cover crops on the corn yield potential and the amount of biomass that can be produced by the cover crops in the fall and spring.  Yield impacts would influence the economics and the potential for crop insurance on interseeded fields. Field trials were conducted at a total of 15 locations in PA, NY and MD to assess the impact of interseeding several cover crop mixes (annual ryegrass, annual ryegrass and legumes, and a legume mix) on corn yield and cover crop biomass production.  Averaged over all locations, interseeded cover crops had no significant impact on corn yields.  At individual locations, corn yields were increased compared to the control with cover crops in some situations and decreased in a few others.  Fall cover crop biomass varied among species and locations but overall averaged   approximately 300 kg/ha DM.   Spring cover crop biomass often was higher than the fall except in cases where severe winterkill or injury occurred.  These results show that interseeding is a viable means of establishing cover crops in many environments and yield impacts tend to be small or non-existent.  Future work should focus on developing techniques to improve the biomass production in the fall and spring.