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Tongcheng Fu, Bokeun Ha and Jonghan Ko

Abstract

The potential doubling of atmospheric CO2 concentration and associated changes in temperature and precipitation are crucial issues for agricultural productivity. The CROPGRO-Soybean model in decision support system for agro-technology transfer v4.5 to simulate soybean (Glycine max cv. Pioneer 93B15) grown in an elevated CO2 environment was calibrated and validated. Crop growth and yield data were obtained from a series of experiments conducted in central Illinois at the soybean free air CO2 enrichment facility from 2002 to 2006. The model was applied to simulate the possible impacts of climate change on soybean yield in the region for the future years of 2080-2100, centred on 2090. The model reproduced the measured soybean growth and yield well under ambient and elevated CO2 conditions. For the period from 2081 to 2100, soybean yield was projected to decrease due to elevated temperature but to increase due to elevated precipitation and CO2 concentration, achieving counterbalance. The adverse impacts of the warming conditions on soybean yield can be mitigated by late planting within an optimum planting range (day of year 145 to 152) as a management option, as well as by controlling genetic responses to thermal days in the reproductive stage.

Open access

Tongcheng Fu, Jonghan Ko, Gerard W. Wall, Paul J. Pinter, Bruce A. Kimball, Michael J. Ottman and Han-Yong Kim

Abstract

Potential impacts of climate change on grain sorghum (Sorghum bicolor) productivity were investigated using the CERES-sorghum model in the Decision Support System for Agrotechnology Transfer v4.5. The model was first calibrated for a sorghum cultivar grown in a free air CO2 enrichment experiment at the University of Arizona, Maricopa, Arizona, USA in 1998. The model was then validated with an independent dataset collected in 1999. The simulated grain yield, growth, and soil water of sorghum for the both years were in statistical agreement with the corresponding measurements, respectively. Neither simulated nor measured yields responded to elevated CO2, but both were sensitive to water supply. The validated model was then applied to simulate possible effects of climate change on sorghum grain yield and water use efficiency in western North America for the years 2080-2100. The projected CO2 fertilizer effect on grain yield was dominated by the adverse effect of projected temperature increases. Therefore, temperature appears to be a dominant driver of the global climate change influencing future sorghum productivity. These results suggest that an increase in water demand for sorghum production should be anticipated in a future high-CO2 world.