Monday, November 5, 2007 - 2:35 PM
61-5

Irrigation in Water Restricted Regions: Managing Water Use Efficiency with Limited Available Water.

Diane Rowland1, Giovanni Piccinni2, Terry A. Howell3, Jonghan Ko4, Thomas Marek2, Wilson Faircloth5, Paxton Payton5, and David Tissue6. (1) USDA-NRCS, USDA-ARS Nat'l Peanut Research Lab, PO Box 509 1011 Forrester Dr. Se, Dawson, GA 39842-0509, (2) Texas A&M University, Texas Agricultural Experiment Station, 1619 Garner Field Rd., Uvalde, TX 78801-6205, (3) Conservation and Production Research Laboratory, USDA-ARS, P.O. Drawer 10, Bushland, TX 79012, (4) Texas Agricultural Experiment Station, Texas A&M University, 1619 Garner Field Road, Uvalde, TX 78801-6205, (5) USDA-ARS, National Peanut Research Laboratory, 1011 Forrester Dr. SE, Dawson, GA 39842, (6) Texas Tech University, Dept. of Biological Sciences, PO Box 43131, Lubbock, TX 79409

Political and social pressure to increase water-use efficiency in agriculture from plant to regional scales is reaching critical levels.  A region where these pressures have been extremely acute is in most semi-arid parts of Texas where crop production is only possible through irrigation. Regulations restricting water use from underground aquifers, increased urban competition for water, coupled with drought during crop production continue to place a large strain on aquifers and water resources in the Edwards and Ogallala aquifer regions.  Irrigation in these two intensively cropped areas is often mismanaged.  A better understanding of how much and when to apply water, whether based on ETc values derived from climatic models, direct crop water use measurement, or precise soil moisture monitoring, can be the basis for improved irrigation management and optimum application rates.  One research approach targeted at increasing water-use efficiency is based on the understanding that the plant available water needed to sustain transpiration and avoid water stress is not a fixed quantity but depends on the atmospheric demand.  Thus, the possibility of managing water restrictions depends on the average atmospheric demand for the period between irrigations. Another approach has aimed at developing irrigation schemes that maximize crop production in this environment while reducing overall water consumption through the use of early season deficit irrigation and increased crop tolerance to late season drought.  Furthermore, we are conducting studies to develop more accurate and region-specific crop coefficients, improving the precision of weather-based irrigation scheduling for economically-important crops in Texas.  These results provide applicable solutions to growers that increase water-use efficiency while maintaining economic viability under water scarcity.  The environmental and economic impact of this research is measured in terms of water savings and net returns to farmers.

Back to Symposium--Yield Response to Water: Physiological Analysis of Crop Water Use and Efficiency
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Back to The ASA-CSSA-SSSA International Annual Meetings (November 4-8, 2007)