Summer survival is a major limitation to interseeding Poaceae cover crops in Kentucky

Abstract

AbstractInterseeding cover crops (CCs) may increase adoption in corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotations in areas with a limited establishment window after harvest. Interseeding could provide an additional use for grass varieties that have been developed from breeding programs. Interseeded CC species must survive through the summer, not cause yield loss in the main cash crop, and produce sufficient biomass to provision ecosystem services. We examined the potential of locally adapted forage grasses, most from the University of Kentucky's grass‐breeding program, as CCs interseeded in corn using field trials conducted over 2 yr (2016 and 2017) in Lexington and Princeton, KY. Grasses were drill‐interseeded when the corn was V5 or V6; density was measured through the summer and biomass measured the following spring prior to CC termination. Percent establishment was generally higher for the festulolium cultivars (× Schedolium braunii (K. Richt.) Stace [Schedonorus pratensis × Lolium perenne ssp. multiflorum]), one of the larger‐seeded entries. In all but one site‐year, most of the forage grass plants did not survive the summer, and biomass by the following spring was minimal. Tall fescue (Festuca arundinacea Schreb.) had the best summer survival in most site‐years though spring biomass prior to termination was less than 1700 lb acre−1 (1905 kg ha−1). Establishment of cool‐season interseeded CCs will remain a challenge in Kentucky due to hot summer temperatures. Future research on interseeding CCs in this region should focus on finding tolerant species as well as evaluating soil and crop management strategies to support interseeding CCs.