SENSITIVITY ANALYSIS OF CERES-WHEAT MODEL TO VARIOUS WEATHER AND NON-WEATHER PARAMETERS FOR WHEAT (CV.GW-496)

Abstract

The CERES-wheat model was calibrated and validated based on actual data of field experiments with an objective to test the sensitivity of model to various weather and nonweather parameters for wheat (GW-496) in middle Gujrat Agro-climatic region, Anand (Gujarat, India). The results showed that grain yields as simulated by the CERES-wheat (cv. GW-496) model due to alteration of ambient temperature in incremental units showed a gradual decrease in yield, while the down scaled ambient temperature was observed to have increased the yield by 2 and 6 % at 4 and 5 °C reduction in temperature respectively. The percentage values of change in the yield were 2 and 8 at –1 and –5 °C over the base yield respectively in case of down scaled ambient temperature under suboptimal conditions. Increase in daily solar radiation (3 to 5 MJm-2), resulted into nearly 6 to 9 % increase in yield over the base yield. Under gradual decrease of solar radiation no yield increment over the base yield was observed. This showed that the model was less sensitive to solar radiation than it was to temperature. When carbon dioxide (CO2) concentration was doubled, the grain yield increased up to 43 % over the base yield in optimal conditions, while corresponding yield increment under sub-optimal conditions was 73%. This showed that the model used had the potential for assessing impact of climate change on wheat production. Large yield reductions were noted under increasing plant population (150 to 500 sq. per mts ) both in optimal and sub-optimal conditions. This provided strong evidence in respect of the robustness of the model to account for the effects of plant population.