Zinc Sulfate and Urea Ammonium Nitrate Interaction Effects on Corn-Cotton Production System

Zinc (Zn) deficiency has been observed in corn and cotton in certain parts of the Mississippi Delta region, where soils are low in organic matter content generally less than 1%. The application of Zn fertilizer in these low organic matter soils might increase corn and cotton yields. Therefore, a field experiment was conducted at the Delta Research and Extension Center, Stoneville, MS from 2018 to 2020 to evaluate the interactive effects of Zn sulfate and urea ammonium nitrate fertilizer application rates on crop yields, soil properties, and Zn uptake in a corn-cotton cropping system. The experimental design was a randomized complete block with five replications. Corn-Cotton rotation was maintained with each phase of crop appearing every year. Urea ammonium nitrate was applied at four rates (Corn: 160, 200, 240, and 280 lb N/acre; Cotton: 30, 60, 90, and 120 lb N/acre). Zinc sulfate was applied at the rate of 0, 5, 10, and 15 lb Zn/acre. Zinc concentration in corn biomass was highest (45 mg/kg) with  280 lb N/acre + 15 lb Zn/acre application compared to all other treatments. Zinc uptake in corn biomass was 4 lb Zn/acre greater for 280 lb N/acre + 15 lb Zn/acre treatment compared to 280 lb N/acre treatment. Corn grain yield was 214 bu/acre for 280 lb N/acre + 15 lb Zn/acre treatment, which was 14 bu/acre higher yield compared to 280 lb N/acre treatment. Seed cotton yield range between 2410 to 3241 lb/acre among different treatments and was highest for 120 lb N/acre + 10 lb Zn/acre treatment.