Cotton Growth and Yield Response to Slow-Release Nitrogen Fertilizers

While nitrogen (N) source, rate, placement and timing of application are important considerations for cotton production, so is the impact of N on water resources. Slow-release N fertilizers have potential to improve N use efficiency in several crops including cotton, and thus reduce N losses to water resources. A first-year field study was initiated in a river bottom soil with a low to moderate residual N level as determined by deep soil sampling. Fertility treatments included a control or 0 N added and 40, 60, 80 and 100 pounds of N per acre added using liquid urea ammonium nitrate (UAN). Six slow-release N products were blended at recommended ratios with liquid UAN fertilizer and applied at 80 and 100 pounds of N per acre. Fertility treatments were initiated by a subsurface band placement of fertilizer at six inches and second true leaf stage. Experimental plots were arranged in a randomized complete block design and replicated five times. Notes on maturity and growth were collected during the season. Lint yield and fiber quality were collected at harvest.