Forecast El NiÑo–Southern Oscillation Phases and Best Irrigation Strategies to Increase Cotton Yield

Equatorial Pacific sea surface temperatures cause a systematic El Niño-Southern Oscillation (ENSO) coupling with the atmosphere to produce predictable weather patterns in much of North America. Forecast ENSO phases and dependent rain have been related to modeled grazing and grain production for limiting risk of dual purpose wheat production in Texas. Similarly, irrigation management could be varied by ENSO phase to improve lint production for forecast growing season conditions. Our objective was to optimize partial pivot deficit irrigation strategies based on simulated cotton lint yield response to irrigation capacity and duration during different ENSO phases for the Texas High Plains. We used, GOSSYM, with ENSO phase specific weather records during 1959-2000 at Bushland, TX to simulate net lint yields of cotton grown with 50 or 75% initial soil water contents for all possible combinations of irrigation duration (0, 4, 6, 8, and 10 weeks) and rate (2.5, 3.75, and 5.0 mm/d). Forecasting early growing season, June, ENSO phase conditions often differed from the maturing phases of fall, but the most consistently classified La Niña phase had limited rain that depressed lint yields below the wetter Neutral and El Niño phases. Deficit irrigation strategies that focused fixed water resources on a smaller area were well suited to conserve or increase net yield during the drier and warmer La Niña phase conditions. Favorable rain during both El Niño and Normal phase years increased net lint yield for irrigation strategies that spread water over larger areas except when both initial soil water and irrigation amount were limiting.