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United States Department of Agriculture

Agricultural Research Service

Title: THE RSML SPAR FACILITY: A TOOL FOR CROP MODELING AND CLIMATE

Authors
item Baker, Jeff
item Timlin, Dennis
item Reddy, Vangimalla
item Acock, Basil

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2000
Publication Date: N/A

Interpretive Summary: The development and testing of crop simulation models require the ability to precisely control major environmental variables to which crops respond. Outdoor, naturally sunlit, plant growth chambers referred to as SPAR (Soil Plant Atmosphere Research) units provide precise control of the major environmental variables influencing crop growth. These factors include temperature, humidity, and atmospheric C02 concentration. Major advantages of the SPAR facility include entire growing season experiments conducted with natural sunlight and realistic rooting volume. The SPAR units are fully automated to measure crop canopy gas exchange over short time intervals for an entire growing season. Global climate change may result in both increases in atmospheric C02 concentration and increases in air temperature and shifts in precipitation patterns. Due to this, it is highly desirable to have the capability to examine crop responses to combinations of these environmental variables. For example, a number of SPAR experiments have been conducted to determine the interactive effects of different levels of C02 and air temperature on major agronomic crops including rice, soybean, wheat, and cotton at the University of Florida and Mississippi State University. This poster illustrates many of the uses of the SPAR facility currently under development.

Technical Abstract: At the heart of mechanistic process-level, crop simulation models are rate equations which describe the physiological responses of crop plants to environmental variables. In order to develop these rate equations, experiments are conducted under carefully controlled environmental conditions. Outdoor, naturally sunlit, plant growth chambers referred to as SPAR (Soil Plant Atmosphere Research) units provide precise control of the major environmental variables influencing crop growth including temperature, humidity, and atmospheric C02 concentration. Major advantages of the SPAR facility include entire growing season experiments conducted with natural sunlight and realistic rooting volume. The SPAR units are fully automated to measure crop canopy gas exchange including photosynthesis, respiration, transpiration, and water use efficiency at 300 intervals. Global climate change may result in not only increases in atmospheric C02 concentration but also increases in air temperature and shifts in precipitation patterns. Due to this, it is highly desirable to have the capability to examine crop responses to factorial combinations of these environmental variables. For example, a number of SPAR experiments have been conducted to determine the interactive effects of different levels of C02 and air temperature on major agronomic crops including rice, soybeans, wheat, and cotton at the University of Florida and Mississippi State University.

Last Modified: 9/1/2014
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