Nitrogen and potassium fertilization strategies in integrated systems in different black oat management on corn crop

This study aimed to evaluate levels of potassium and nitrogen fertilizer inversion in the black oat crop on corn crop yields. The experimental design was a randomized block design with subdivided plots with three repetitions. The treatments were four nitrogen fertilization strategies, four potassium fertilization strategies, and two oat crop managements (forage and cover crop). The strategies involved winter (oats) and summer (corn) application, respectively, with the following combinations of nitrogen (200-0; 150-50; 50-150; 0-200 kg N ha-1) and potassium (80-0; 60-20; 20-60; 0-80 kg K ha-1). We evaluated the morphological aspects, grain productivity, chlorophyll contents, and light interception of oats for forage production and ground cover, and for corn the yield components and productivity. Oats managed as forage showed higher forage mass production but lower values of residual biomass, canopy height, extended tiller length, lodging index, radiation interception, and oat chlorophyll A and total. Light interception in the oat crop was higher when nitrogen was applied in the pasture. For the corn crop, nitrogen applied partially on black oat and the remaining on corn row crop increases stalk diameter. Fertilization strategies showed no significant effect on both crops in the system, indicating that it is possible to reverse or apply the entire amount of N and K predicted for the two crops in winter.