Replicated field experiments were conducted at multiple locations on soils commonly used for cotton production in Arkansas during the 2006 and 2007 cropping seasons to evaluate the effect of sidedressed N-fertilizer rate on seedcotton yield and petiole NO3-N concentration, and to identify soil presidedress soil test nitrate levels beyond which no agronomic yield response to N fertilizer will be expected.  Nitrogen fertilizer was applied in split applications at total-N rates of 0, 30, 60, 90, 120, and 150 lb N/acre.  Prior to, or at planting, 20 lb N/acre as ammonium sulfate was applied to all treatments except the 0 lb N/acre treatment. The balance of each total-N rate was sidedressed at first square stage. Prior to the application of sidedressed N, soil samples were collected by replication from the 0-to 12-inch soil depth and soil nitrate nitrogen were measured. Seedcotton yield, leaf nitrogen and petiole nitrate nitrogen were measured.