Location: Soil and Water Management ResearchTitle: Crop water production functions of grain sorghum and winter wheat in Kansas and Texas
|MOBERLY, JOSEPH - Kansas State University|
|AIKEN, ROBERT - Kansas State University|
|LIN, XIAOMAO - Kansas State University|
|SCHLEGEL, ALAN - Kansas State University|
|Baumhardt, Roland - Louis|
Submitted to: Journal of Contemporary Water Research and Education
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2017
Publication Date: 12/1/2017
Citation: Moberly, J., Aiken, R.M., Lin, X., Schlegel, A.J., Baumhardt, R.L., Schwartz, R.C. 2017. Crop water production functions of grain sorghum and winter wheat in Kansas and Texas. Journal of Contemporary Water Research and Education. 162:42-60.
Interpretive Summary: As water available for irrigation from the Ogallala Aquifer decreases, dryland farming will become more common place on the Southern High Plains. Farmers will need information on dryland yield potential based on weather forecasts to determine the optimum levels of inputs. However, currently the ability to predict wheat and sorghum yields are rather limited. Therefore, ARS scientists from Bushland, Texas worked with researchers in the Ogallala Aquifer Program at Kansas State University with the objective to better forecast dryland sorghum and wheat grain yields from weather variables and water use. Crop production functions relating water use and grain yield were developed based on the Kansas Water Budget (KSWB). The KSWB model was found to be an useful decision support tool for relating water supply to grain yield. In the future farmers may be able to combine short term weather forecasts (30-90 days) with KSWB to determine yield potentials and the optimum levels of inputs including irrigation applications.
Technical Abstract: Productivity of water-limited cropping systems can be reduced by untimely distribution of water as well as cold and heat stress. Our study objective was to develop relationships among weather variables, water use, and grain productivity to produce production functions for forecasting grain yields of sorghum and winter wheat in water-limited cropping systems. The relationship of grain yield to crop water use, reported in several crop sequence studies conducted in Bushland, TX, Colby and Tribune, KS, were compared against the Kansas Water Budget (KSWB) modeling results. Field studies showed that winter wheat had stable grain yields over a wide range of crop water use, while sorghum had a wider range of yields over a smaller distribution of crop water use. The relationship of winter wheat yield to crop water use, simulated by KSWB, was comparable to relationships developed for four of five studies, except for one study conducted in Bushland that suggested less crop water productivity. For grain sorghum, experimental yield response to an increment of water use was less than that calculated by KSWB for three of five cases; for one study at Colby and Tribune, simulated and experimental yield response to water use were similar. Simulated yield thresholds were consistent with observed yield thresholds for both wheat and sorghum in all but one case. The KSWB model provides a useful analytic framework for distinguishing water supply constraints to grain productivity.