Submitted to: Proceedings of the Central Plains Irrigation Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/17/2009
Publication Date: 2/24/2009
Citation: Colaizzi, P.D., Evett, S.R., Howell, T.A., Baumhardt, R.L. 2009.Comparison of grain sorghum, soybean, and cotton production under spray, LEPA, and SDI. In:Proceedings of the Central Plains Irrigation Conference and Exposition, February 24-25, 2009, Colby,Kansas. p.122-139. Interpretive Summary: Irrigation is important for crop production in the U.S. Great Plains. Several types of advanced irrigation systems are available, including self-propelled sprinkler systems (center pivots being the most common) and subsurface drip irrigation (where water is delivered directly in the soil by buried flexible tubing). Both sprinkler and drip can be more efficient than furrow irrigation (where water is applied so that it runs down the furrows between the crop rows), provided that irrigations are properly managed. We compared crop production under sprinkler and drip irrigation; crops included grain sorghum, soybean, and cotton. In most cases, greater crop production was observed with drip irrigation. This was probably because drip irrigation results in less evaporative losses compared with sprinkler irrigation, and also results in warmer soil temperatures. However, sprinklers sometimes resulted in greater grain sorghum and soybean production if too much irrigation water was applied. These results show that drip irrigation may result in greater crop productivity than sprinkler irrigation under proper irrigation management. Also, drip may be advantageous for cotton production where it is produced in cooler climates, such as the Northern Texas Panhandle or Southwestern Kansas.
Technical Abstract: Crop production was compared under subsurface drip irrigation (SDI), low energy precision applicators (LEPA), low elevation spray applicators (LESA), and mid elevation spray applicators (MESA) at the USDA-Agricultural Research Service Conservation and Production Research Laboratory, Bushland, Tex., USA. Each irrigation method was compared at irrigation rates meeting 25, 50, 75, and 100% of full crop evapotranspiration (ETc). Crops included three seasons of grain sorghum, one season of soybean (planted following a cotton crop that was destroyed by hail), and four seasons of upland cotton. For grain sorghum, SDI followed by LEPA, MESA, and LESA resulted in greater grain yield, water use efficiency, and irrigation water use efficiency at the 25- and 50% irrigation rates, whereas MESA followed by LESA outperformed LEPA and SDI at the 75- and 100% irrigation rates. For soybean, the same trend was observed at the 25- and 50% irrigation rates, whereas SDI followed by MESA, LEPA, and LESA resulted in the best crop response at the 75% irrigation rate, and MESA followed by SDI, LESA, and LEPA resulted in the best crop response at the 100% irrigation rate. Cotton response was consistently best for SDI, followed by LEPA, and either MESA or LESA at all irrigation rates. Within each irrigation rate, few significant differences were observed among irrigation methods in total seasonal water use for all crops.