Tillage and Nitrogen Application Impact on Cotton following Wheat

Received for publication June 2, 2004. Tillage and N fertilization influence cotton (Gosspium hirsutum L.) growth and yield. The objective of the study was to evaluate the influence of two tillage systems (conventional tillage [CT] and strip-till [ST]) and four N rates (0, 67, 134, and 202 kg N ha-1) on growth, development, and yield of ‘DP 5409’ cotton following wheat (Triticum aestivum L.). The experiment was conducted at the University of Floridaʹs North Florida Research and Education Center in Quincy, FL, in 1995-1997. Lint yields, plant height, boll no. plant-1, and boll no. m-2 varied across years. With every 1 kg N ha-1 applied to cotton, lint yields increased by 1.74 and 1.53 kg ha-1 in 1996, and 2.76 and 1.76 kg ha-1 in 1997 for CT and ST, respectively. In 1995, maximum lint yields were estimated with 105 kg N ha-1 for CT. Averaged across years, cotton lint yield increase with N application greater than 67 kg ha-1 was not significant and tillage did not influence lint yields. Plant height, boll no. plant-1, and boll no. m-2 generally increased with increasing N rates, except for boll no. m-2 in the ST system in 1995. Greatest boll weight and lint weight boll-1 were obtained with the application of 134 kg N ha-1. Compared with CT, ST reduced boll no. plant-1 and increased boll no. m-2. Tillage did not influence plant height, boll weight, and lint weight boll-1. These results indicate that cotton can be grown successfully in ST and that yields may not increase significantly with rates >67 kg N ha-1.