Effects of Cultivar Maturity, Nitrogen and Irrigation Rates On the Physiology and Yield of Cotton

Since the droughts of 2007 in TN, the acreage of cotton under irrigation in humid regions has increased. This has resulted in a surge of questions from producers on when and how much irrigation to apply and whether the recommended nitrogen application rates should be different for rainfed vs. irrigated cotton. Additional questions followed... Can we improve yield and reduce irrigation costs by applying different irrigation rates at different growth stages? Do irrigation and nitrogen recommendations depend on the maturity or determinancy of the variety selected? This study was conducted to address these questions and to assess the combined effects and interaction of cultivar maturity, nitrogen application rate, and irrigation rates at different growth stages on lint yield. Physiological and morphological parameters were measured at various growth stages to determine factors most affected by different nitrogen and irrigation treatments that may ultimately influence lint yield.