ABSTRACT

Three out of ten years in South Texas are marked with high rainfall in the first 60-90 days of the growing season. Frequently, this cotton is subjected to poor surface drainage and substantial nitrogen losses occur which result in reduced lint yields. Cotton growing at fifteen Texas Coastal Bend locations was evaluated for response to applications of foliar urea beginning at the onset of chlorosis. Individual and supplemental treatments of PGR IV were also made at selected test locations so that each product could be evaluated for its own effect, as well as any additive effects. Applications were made at times least damaging to cotton leaves; however, some concessions were necessary to evaluate application effects. Favorable increases in lint yields were observed under conditions of light root damage and chlorosis, where lint yields exceeded one bale/acre (locations without serious stunting and fruit shed). Seriously damaged cotton (< 1 bale/acre cotton) did not respond to any treatment in a cost-effective manner. Eighty percent of all yield increases were attributed to increased boll numbers and twenty percent was attributed to increased boll weight. Favorable results were obtained from both foliar nitrogen and PGR IV when used individually. Combined treatments on low yield cotton were not successful. Use of foliar urea does not replace the need for adequate soil-applied nitrogen. Foliar urea is recommended only as a supplemental treatment to maintain favorable nutrition for cotton with (projected) higher yield potential.