Tuesday, 8 November 2005 - 8:45 AM
132-4

Testing Elevated Temperature Responses of the Cropgro-Peanut Model with Data from Sunlit, Controlled-Environment Chambers.

Kenneth Boote1, P. V. V. Prasad1, and L. Hartwell Allen Jr.2. (1) University of Florida, Agronomy Dept., Gainesville, FL 32611-0500, (2) USDA-ARS, P.O. 110965, University of Florida, Gainesville, FL 32611-0965

It is important that crop models be able to accurately predict crop growth and yield responses to adverse weather including elevated temperatures. Our objective was to test the CROPGRO-peanut model against data from sunlit, controlled-environment chambers and verify model temperature functions for photosynthesis, vegetative, and reproductive processes. Peanut was grown from emergence to maturity in sunlit, controlled-environment chambers at temperatures ranging from 32/22 to 44/34°C diel Tmax/Tmin at ambient and elevated CO2. Final harvest measurements were based on 1 by 2 m land area. The temperatures, solar radiation, and CO2 levels were input into the model. The CROPGRO-peanut model, with no modification, was surprisingly accurate in predicting the elevated temperature sensitivity of pod yield, seed yield, seed number, and seed harvest index (HI). Pod yield, HI, and seed size were highest for the 32/22°C treatment, while total biomass was highest at 36/26 to 40/30°C. While yield was somewhat over-predicted at 32/22°C, the model accurately predicted the decline in yield to nearly zero as temperature increased to 44/34°C. The simulated decline in yield, HI, seed number and seed size, while generally well predicted, was too rapid with advancing temperature, and was improved with a 4°C increase in the ceiling temperature for the quadratic functions affecting pod addition rate and seed growth rate. With these changes, the temperature declines of pod yield, seed yield, HI, seed number, and seed size were improved, and predictions reached zero at 45/35°C. The predicted response to doubling of CO2 for biomass and pod yield was comparable to the observed response. These studies from sunlit, controlled-environment chambers were valuable for testing model responses to temperature.

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