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Water‐Yield Relationships for Irrigated and Dryland Wheat in the U.S. Southern Plains
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1994
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Linear Regression ResponseEngineeringLand UseCropping SystemAgricultural EconomicsWater‐yield RelationshipsU.s. Southern PlainsEarth ScienceIrrigation ManagementAgricultural Water ManagementSustainable AgriculturePublic HealthAgricultural EfficiencyCrop YieldCrop Water RelationIrrigationCrop Growth ModelingWater DeficitsDryland WheatDroughtAgricultural ModelingFarming SystemsEt Threshold
High evaporative demand and limited precipitation in the semiarid U.S. southern High Plains constrain winter wheat yields, but these stresses can be mitigated by practices that increase soil water storage at planting or by irrigation. The study aimed to develop grain yield and water‑use efficiency relationships across a wide range of seasonal evapotranspiration and to assess yield response to stored soil water at planting using a 178‑crop‑year database from Bushland, TX. Researchers analyzed the 178‑crop‑year irrigated and dryland wheat dataset, applying linear regression to relate grain yield to seasonal evapotranspiration and to soil water stored at planting.
Abstract A climate with high evaporative demand and limited precipitation restrict yields of winter wheat ( Triticum aestivum L.) grown in the semiarid U.S. southern High Plains. Stress effects can be avoided or minimized by management practices that increase soil water storage at planting or by application of irrigation water. We analyzed a 178 crop‐year database of irrigated and dryland wheat data from Bushland, TX, to develop relationships that define the grain yield and water‐use efficiency (WUE) response to a wide range in seasonal evapotranspiration (ET) associated with water deficits and to evaluate yield response to stored soil water at planting. The ET‐grain yield relationship was determined as linear, with a regression slope of 1.22 kg grain per m3 ET above the ET threshold of 208 mm required to initiate grain yield. Maximum yields (>7.0 Mg ha −1 ) required 650 to 800 mm seasonal ET. Maximum yields observed in the combined database were 2.8 and 8.2 Mg ha −1 for dryland and irrigated wheat, respectively. The linear regression response of grain yield to soil water stored at planting, 1.57 kg m −3 , was significantly higher than the yield response to seasonal ET. Largely similar WUE values occurred over a wide range of seasonal ET within irrigated and dryland data sets; however, WUE values for irrigated wheat averaged about double the values for dryland wheat. A curvilinear relationship determined between WUE and yield emphasizes the importance of obtaining high yields for efficient water use.