Tests were conducted in 2004 and 2005 to determine if additional nitrogen fertilizer was needed by cotton grown with conservation tillage. The dryland test area consisted of conservation residues of corn, soybeans and cotton as well as wheat cover crop residue with and without tillage. These tests were conducted in small plot research areas where recommended cotton fertilizations rates were compared to nitrogen fertilizer rates increased an additional 30 pounds per acre. Nitrogen fertilizer rates on irrigated cotton were conducted in a large field trial, where plots were four rows wide and planted into a wheat cover crop. Nitrogen fertilizer rates of 90,110, and 130 pounds per acre were compared across the field in eight replications. Preliminary results indicate that additional nitrogen fertilizer may be needed on dryland cotton if planted into crop residue or a wheat cover crop. In 2004 irrigated cotton yields were still increasing when nitrogen fertilizer rates of 130 pounds per acre were applied.