Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2005
Publication Date: December 1, 2005
Citation: Tolk, J.A., Howell, T.A., Evett, S.R. 2005. An evapotranspiration research facility for soil-plant-environment interactions. Applied Engineering in Agriculture. 21(6):993-998. Interpretive Summary: The Soil-Plant-Environment Research (SPER) facility was opened in 1990 at the ARS Conservation and Production Research Laboratory, Bushland, TX, for the purpose of studying how soil characteristics such as water holding and water transmission capacities affect crop growth and irrigation management practices. The facility had undisturbed soil cores of three major Great Plains agricultural soil series that were contained in large metal boxes (lysimeters) that could be picked up and weighed so water loss (evapotranspiration, or ET) could be determined on a weekly basis. A shelter that automatically covered the lysimeters during a rain allowed control of water applications for irrigation research. The facility has now been upgraded with the addition of a fourth soil type that increases the range of soil nutrient and water holding chacteristics, the installation of 48 deck (platform) scales for the continuous measurement of ET, and the use of a pressure-compensating drip system for easy, accurate irrigation applications. These improvements to the SPER facility will expand the type and quality of plant stress and irrigation management research projects that can be performed.
Technical Abstract: The Soil-Plant-Environment Research (SPER) facility at USDA Agricultural Research Service at Bushland, TX, opened in 1990 with 48 weighable lysimeters containing monolithic soil cores of three major soil groups and a rain shelter. Its purpose was to provide an environment for intensive plant water stress research and evaluate the impact of soil hydraulic characteristics on irrigation management strategies. The facility has now been upgraded with the addition of a fourth soil type collected using static weights, the installation of 48 deck (platform) scales for the continuous measurement of evapotranspiration (ET), and the use of a pressure-compensating drip system. The additional soil was selected to provide a wider range of nutrient and water supplying capacity compared with the other three soils. The conversion to weighing lysimeters allows the collection of diurnal ET data needed for plant physiological studies and validation of ET measurement equipment and models. The drip system reduces labor, increases precision of application amount, and reduces disturbance around the lysimeters. These improvements to the SPER facility will expand the type and quality of plant stress and irrigation management research projects that can be performed.