The nitrogen rates that produce optimum cotton growth and yield vary widely among soil types and with cropping history. Researchers in Louisiana have for many years conducted nitrogen studies to determine the best nitrogen management practices for specific situations. From these studies optimum rates were identified for Mississippi River alluvial and loess silt loam (60 to 80 lb/a), clay (90 to 120 lb/a), Red River alluvial silt loam (60 to 110 lb/a), and Red River alluvial sandy loam (60 to 80 lb/a). The optimum rates varied within the soil types depending upon cropping history and other factors. In Louisiana splitting the fertilizer nitrogen has not increased yield or fertilizer efficiency. Cropping practices that affect the fertilizer nitrogen requirements of cotton include crop rotation, winter cover crops, irigation and tillage. Cropping practices that do not affect fertilizer nitrogen requirements include row spacing and plant density.