ICASALS 2006 poster Peanuts and deficit irrigation

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Effects of Deficit Irrigation and Temperature Stress on Peanut Production Paxton Payton1, David Tissue2, Wilson Faircloth3, and Diane Rowland3 1USDA-ARS Cropping Systems Research Laboratory, Lubbock, TX USA 2Department of Biological Sciences, Texas Tech University, Lubbock, TX USA 3USDA-ARS National Peanut Research Laboratory, Dawson, GA USA Figure 5. Effect of soil surfactant application to peanut yield in West Texas. A. Mid-season photosynthetic rates under 50%, 75%, and 100% irrigation. Photosynthesis was measured in both Control test plots (no product applied; red bars) and test plots with applied surfactant (blue bars). B. Total yield for the 2006 growing season for test plots (red bars) and plots with applied surfactant (blue bars). Irrigation treatments have been combined into drought period application (ALL = drought throughout the season, NONE = 100% irrigation application; E, M, L signify drought during early, mid, and late season respectively and combinations of drought periods. Asterisks denote significant differences at p < 0.1 level. Effect of Soil Surfactant Application on Irrigation Efficiency Summary Deficit irrigation results in moderate decreases in total yield and maturity. Early season deficit irrigation (50% of control) up to 80 DAP reduced mature yield approximately 15% and total yield by 16%. Mid- to late-season deficit irrigation resulted in 20-30% yield and mature yield reductions. Reduced yield and maturity are correlated with late day reductions in photosynthesis and stomatal conductance in the test plots during mid- to late-season growth. Photosynthetic rates declined as much as 70% in the afternoon for plants grown under 50% irrigation rate, compared to a 40% decline in control plants and late season declines on 45% in the 75% treatment. The use of soil surfactants increased yield under deficit irrigation compared to plots with no surfactant. In several treatments, yield was significantly increased compared to the full irrigation treatment. The use of soil surfactants to ameliorate water repellency in managed systems has been well documented. We tested the effect of a commonly used soil surfactant, IrrigAid Gold (Aquatrols, Paulsboro, NJ USA), on peanut production under deficit irrigation in west Texas for the 2006 growing season. Figure 2. Soil volumetric water content (VWC) was measured at 8, 16, and 24 inch depths throughout the growing season for all treatments. Data shown represent VWC in the 50% and 100% treatments. Effects of Deficit Irrigation on Peanut Physiology and Yield USDA-CSRL Marie Syapin Kayla McCartor JR Quilantan Michael Metzler Texas Tech University Andrew Tredennick Erica Chipman Blake Watkins Ntaasja van Gestel USDA-NPRL Larry Powell Chris Butts Manuel Hall Acknowledgements Figure 1. Effect of deficit irrigation on photosynthesis and stomatal conductance. Gas-exchange was measured at 45 (Early), 80 (Mid), and 125 (Late) Day After Planting (DAP). Treatments included 50% (red bars), 75% (yellow bars), 100% (blue bars) irrigation for the entire season. Additionally, 50% (purple bar) and 75% (green bar) irrigation levels were applied through mid-season, followed by 100% irrigation during late season pod set and development. Photosynthesis and conductance were measured approximately 5 hrs. (solid bars) and 10 hrs (hashed bars) into the photoperiod to monitor the diurnal change in A and gs in plants 1 day post-irrigation (DPI) and 1 week post-irrigation (7 DPI). Bars represent mean + SE, n=6. Figure 3. A. Effect of timing and severity of deficit irrigation on crop maturity and yield in Texas runner peanuts for the 2005 growing season. Maturity was determined using the hull scrape method. Full maturity for Flavor Runner 458 is > 70% brown/black pods. Irrigation treatments have been combined into drought period application: ALL = 50% irrigation for the entire season; NONE = 100% irrigation application; E, M, L signify drought during early, mid, and late season respectively and combinations of drought periods. Data represent mature yield (percent maturity X total yield). B. Late-day depression of photosynthesis in plants under 50%, 75%, and 100% irrigation during early-, mid-, and late-season growth periods. Data represent the afternoon photosynthetic rates as a percentage of mid-morning (5 hrs. into the photoperiod) rates. A. Introduction Abiotic stresses, particularly water-deficit and high temperature, are the primary factors limiting crop productivity, accounting for more than a 50% reduction in yields worldwide. Compounding the problem of reduced yields is the prediction that the world population will exceed 8 billion by 2030, requiring a doubling of world food production on current arable hectares. Given that most of the Earth’s arable land is already under production and consumes almost 70% of the available freshwater, it is important that we increase food production while reducing water consumption. Cultivated peanut (Arachis hypogaea L.), is both a major food crop and one of the top oilseed crops produced in the world. It is grown on 25 million hectares, with a total global production of 36 million tons. In 2004, the U.S. produced nearly 2 million tons of peanuts and exported over 16,000 metric tons worth $1 billion to farmers and $6 billion to the economy overall. Texas is the second largest producer of peanuts in the United States. In the southern High Plains of west Texas and eastern New Mexico, low natural rainfall (450 mm) requires significant irrigation, and rapid depletion of the Ogallala Aquifer is already limiting crop production. At current rates of water use, it is estimated that this water source will be locally depleted within 30 to 40 years. Therefore, it is extremely important that we develop an irrigation schedule that maximizes peanut production while reducing overall water consumption. Objectives Our overall objective is to develop an irrigation schedule that maximizes peanut maturity and yield, but reduces water consumption, in an economically viable fashion. Our specific objectives are: Determine the impact of deficit irrigation on peanut yield and maturity. Determine whether the yield and maturity response to deficit irrigation is influenced by plant physiology. Determine whether the application of a commercial surfactant affects yield and maturity. 50% 100% 75% This project is supported by: USDA CRIS 6208-21000-013-00D USDA CRIS 6604-21000-002-00 Howard Hughes Medical Institute National Peanut Producers