Climate Change Effects on Texas Dryland Winter Wheat Yields

Wheat offers winter forage for cattle grazing and is one of the most valuable cash crops in Texas. In this study, we evaluate the impacts of climate change projections on winter wheat grain yields in five major wheat producing counties in Texas (Deaf Smith, Ochiltree, Hansford, Moore, and Parmer). For this purpose, extant soil and climate data were utilized in conjunction with Agricultural Policy Environmental eXtender (APEX) and Coupled Model Intercomparison Project-Phase 5 (CMIP 5) climate projections to determine the most reasonable future trajectory of Texas winter wheat yields. The results indicate that Deaf Smith and Parmer counties are projected to experience the greatest yield decrease, 33.33%, about 696 kg/ha under the CMIP5 RCP4.5 (Texas projected temperature increase between 2.2 and 3.3 degrees C) 2046-2070 scenario compared to a 1981-2017 baseline. The maximum percentage yield increase was noticed in Ochiltree County under the CMIP5 RCP8.5 2071-2095 scenario, with an 84.2% (about 1857 kg/ha) yield increase compared to the 1981-2017 baseline. Parmer County is projected to experience the greatest yield decrease of 20%, about 348 kg/ha, under the RCP4.5 2046-2070 scenario when compared to the 1981-2005 baseline. The maximum percentage yield increase is projected for Ochiltree County-a 105.9% increase, about 2089 kg/ha-under the RCP8.5 2071-2095 scenario when compared to the 1981-2005 baseline. In general, with few exceptions, winter wheat yields are projected to rise under the projected climate scenarios.