MECHANISTIC PROCESS-LEVEL CROP SIMULATION MODELS FOR ASSESSMENT OF AGRICULTURAL SYSTEMS
Location: Crop Systems & Global Change
Title: Effects of carbon dioxide and temperature on crops: Lessons from SPAR growth chambers
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: January 15, 2010
Publication Date: September 13, 2010
Citation: Fleisher, D.H., Timlin, D.J., Reddy, K.R., Reddy, V., Yang, Y., Kim, S. 2010. Effects of carbon dioxide and temperature on crops: Lessons from SPAR growth chambers. In: Hillel, D., Rosenzweig, C., editors. Handbook of Climate Change and Agroecosystems: Impacts, Adaptation, and Mitigation. Hackensack, NJ: World Scientific Publishing Co., Inc. p. 55-86.
Sunlit growth chambers, known as Soil-Plant-Atmosphere-Research (SPAR) chambers, provide a unique environment for studying and quantifying the effects of environmental variables, either alone or in combination, on plant growth and development. SPAR chambers are appropriate for short-term or entire growing season experiments, have precise and repeatable environmental controls for atmospheric carbon dioxide concentration (CO2), temperature, water and nutrients, and allow canopy gas exchange measurements. To some extent, vapor pressure deficit can also be controlled. SPAR chambers with soil bins have the advantage of a realistic root volume and have the capability to monitor root growth and water use over the growing season. Because of their small size, SPAR chambers are not appropriate for estimating climate change effects on yields or end-of-season biomass at the field scale for crops that have low planting density requirements. They are uniquely qualified, however, for quantifying plant processes and plant responses to environmental variables over short time periods, minutes to days to months. The environmental conditions in the SPAR (other than light) can be controlled so the plant response will be affected by a minimum of variables. This allows one to develop equations and algorithms where responses are not confounded by varying temperature, vapor pressure deficit or water availability. Canopy-level photosynthesis, transpiration, and plant growth and development rates have been quantified for cotton, maize, potato, rice, soybean, and other crops under varying temperatures, nutrient levels, water regimes and CO2 concentrations. This has provided a large database for the development of functional relationships of plant responses to environmental variables. These algorithms have been incorporated into simulation models for cotton, maize, soybean and potato. Such models are useful for evaluating the effects of elevated temperature and CO2 on plant growth, development and yield at the field scales. We will show several examples of research results from SPAR facilities used to develop process-level crop models for simulations of real-world production environments.