More recent wheat cultivars extract more water from greater soil profile depths to increase yield in the Texas High Plains

Authors: THAPA, SUSHIL - Texas A&M Agrilife; XUE, QINGWU - Texas A&M Agrilife; JESSUP, KIRK - Texas A&M Agrilife; RUDD, JACKIE - Texas A&M Agrilife; LIU, SHUYU - Texas A&M Agrilife; PRADHAN, GAUTAM - North Dakota State University; DEVKOTA, RAVINDRA - Texas A&M Agrilife; BAKER, JASON - Texas A&M Agrilife

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2017
Publication Date: 10/5/2017
Citation: Thapa, S., Xue, Q., Jessup, K.E., Rudd, J.C., Liu, S., Pradhan, G.P., Devkota, R.N., Baker, J. 2017. More recent wheat cultivars extract more water from greater soil profile depths to increase yield in the Texas High Plains. Agronomy Journal. 109(6):2771-2780. https://doi.org/10.2134/agronj2017.02.0064.
DOI: https://doi.org/10.2134/agronj2017.02.0064

Interpretive Summary: Drought is the most important factor limiting wheat yields on the U.S. Southern High Plains. Adoption of suitable cultivars and crop management practices are crucial to reducing yield loss from drought however, the parameters associated with tolerance to drought are not fully known. Therefore, scientists from Texas A&M University and North Dakota State University in the ARS led Ogallala Aquifer Program conducted a 5-yr study to investigate soil water extraction by four wheat cultivars. There were large variations in grain yields (474 to 3,685 kg per ha) in dryland wheat across years and cultivars. Yield was largely determined by plant available soil water at planting and seasonal precipitation. More recent cultivars (TAM 110, TAM 111, and TAM 112) were able to extract more water from deeper in the soil profile than the legacy wheat cultivar, TAM 105, especially during the dry years. This study demonstrated that effective use of soil water from greater soil depths is important for wheat yields on the Southern High Plains.

Technical Abstract: Drought is the most important factor limiting wheat (Triticum aestivum L.) yield in the U.S. southern High Plains (SHP). Adoption of suitable cultivars and crop management practices are crucial to reducing yield loss from drought in the area. We conducted a 5-yr study to investigate the depth and amount of net soil water extraction (SWE) in four wheat cultivars at different growth stages. Plants were grown under dryland conditions and volumetric soil water content (SWC) was measured in 0.2-m increments to the depth of 2.4 m at planting, jointing, anthesis, and maturity. There were large variations in grain yields (474–3685 kg per ha) in dryland wheat across years and cultivars. Yield was largely determined by plant available soil water (PASW) at planting and seasonal precipitation. In a season with high yield (3548 kg per ha in 2016), net SWE occurred in the whole 0.0- to 2.4-m profile. In contrast, in a season with very low yield (650 kg per ha in 2011), net SWE was limited to the upper 1.2 m. More recent cultivars (TAM 110, TAM 111, and TAM 112) were able to extract more water from deeper in the soil profile (particularly between jointing and maturity), and had higher evapotranspiration (ET), biomass, and yield than the legacy wheat cultivar (TAM 105), especially during the dry seasons of 2011 and 2012. This study demonstrated that effective use of soil water from greater soil depths is important for greater ET and yield under dryland conditions in a semiarid environment.