Non-Irrigated Corn Growth & Development Following Cover Crops.

Rye (Secale cereale L.) and oat (Avena sativa L.) cover crops (CC) grown after winter wheat in a winter wheat (Triticum aestivum L.) – corn (Zea mays L.) rotation can produce abundant dry matter, which contributes organic matter and provides winter ground cover and can improve soil health. However, large amounts of grass CC can immobilize soil N and possibly have allelopathic properties, both of which can inhibit growth of corn planted into these fields. In this study, effects of previous rye and oat CC on corn development were assessed. Rye and oat biomass were sampled in the fall & spring of 2015/2016 & 2016/2017. Corn physiological development, diameter and height were measured weekly starting 4 weeks post-planting in both 2016 & 2017. In 2016 yield was not affected by cover crop treatments. In 2017, i) corn stalk diameters in the July-planted rye-oat mix cover crop treatment were smaller than all others until the fourth week, but there were no differences among stalk diameters at the final sample date, ii) corn heights were not affected by the different cover crop treatments, iii) vegetative stages of corn following September-planted rye lagged behind the developmental stages of corn following July-planted rye, and iv) corn reproductive stages were similar for the various cover crop treatments.