Cotton growth stage specific irrigation and fiber quality response in the Great Plains region

With decreasing water availability and increasing cotton (Gossypium hirsutum L.) production in the Great Plains region, a more efficient irrigation schedule and variety response needs to be assessed to make production more sustainable in this arid, short season environment. A two-year study was conducted in Goodwell, Oklahoma to determine a more efficient irrigation schedule using subsurface drip tape (SSD) and evaluating variety response. The performance of four early maturing cotton varieties was assessed under four irrigation treatments based off evapotranspiration (ET) replacement schedules of 90% ET, 63% ET, 90/63% ET, and 36% ET replacement. Crop growth and development, crop maturity, yield parameters, and fiber quality properties were evaluated in response to variety and irrigation schedule. Excessive rainfall and reduced heat units in 2020 resulted in maturity delays, reduced yield, and poor fiber quality. There was minimal effect of irrigation treatments due to the excess rainfall, while differences in growth and yield parameters were present due to variety, with those exhibiting earlier maturing characteristics resulting in a 20 – 30% higher lint yield. Varietal differences were still present when growing conditions improved in 2021, and in this year irrigation treatments also influenced some growth parameters, as well as lint yield. Variety was more impactful on plant growth and development, as varieties exhibiting earlier maturing characteristics in 2020 again had lower node above white flower and height values. The lowest ET replacement irrigation treatment resulted in a 6 – 27% higher open boll percentage compared to all other treatments. The 90% ET and 63% ET treatments had 21 – 34% higher lint yields then all other irrigation treatments. The results of this study illustrate the importance of both correct variety selection and management in irrigated short season production environments