Irrigation Strategies That Use Cutout for Optimum Boll Maturation and Yield Where Growing Season Duration Is Limited

Irrigation water available is decreasing due to greater competition or declining availability of water sources and producers now face compliance with annual pumping restrictions that may challenge overall cotton productivity. This is further complicated by a limited growing season in the Texas Panhandle and Kansas because late season irrigations may not produce mature bolls. The lower chance of maturing bolls from late growing season blooms defines the last effective bloom date (LEBD) and pumping irrigation water to mature fruit forming after the LEBD is a potential waste of water. Cotton matures rapidly after the white flower is within five nodes of the terminal or “cutout” and the plant discontinues further flowering. Imposing water stress during bloom hastened cutout and consequently reduced boll retention, which suggests a mechanism to manage the crop boll load and improve water use efficiency. Our research goal was determining the efficacy of managed water stress to induce cotton cutout corresponding to LEBD for improved boll maturation, lint yield, and quality. Crop growth and yield of cotton receiving typical evapotranspiration replacement irrigations was compared to cotton placed under post bloom water deficit stress to induce cutout. Preliminary data identified some success in improved lint quality factors and inconsistent yield response, but further investigation is needed.