ISPRS Archives XXXVIII-8/W3 Workshop Proceedings: Impact of Climate Change on Agriculture 110 ANALYZING THE IMPACT OF RISING TEMPERATURE AND CO2 ON GROWTH AND YIELD OF MAJOR CEREAL CROPS USING SIMULATION MODEL

Temperature and CO2 are two important parameters related to climate change, which affect crop yield. In this study, an attempt has been made to assess the impact of these two factors on the productivity of the four major cereal food crops (wheat, rice, maize and pearl millet) taking New Delhi as study area. This study also aims at identifying the most sensitive growth phase of these crops to the rising temperature. A soil-plant growth simulator CropSyst model was used for this purpose. Calibrated crop coefficients and soil data of the study area were collected from the previous experiments. Five years’ weather data was used to simulate the actual crop yield under unstressed condition. Maximum and Minimum temperature was increased by 1, 2, 3, 4 and 5 C for whole year. Yield was simulated with different rising temperature scenarios.. Yield was also simulated at present level of CO2 as well as doubled CO2 situation using each of the rising temperature scenarios. To find out the most sensitive growth phase to the change in temperature, maximum and minimum temperature was increased by 1-5 C only during each of the three important phenophases (Emergence to Peak LAI; Beginning of flowering to beginning of grain filling; Beginning of grain filling to beginning of physiological maturity). The difference in yield, biomass, water use in terms of actual evapo-transpiration and total crop duration was estimated and analyzed to assess the effect of elevated CO2 and temperature. All crops showed reduction in yield with increasing temperature. Wheat was the most sensitive crop and maize is the least sensitive crop to temperature rise among the four. Doubled CO2 increased yield at all temperature rise situation. Wheat and rice showed increase in yield up to 2 C rise in temperature at doubled CO2 condition. Maize increase yield up to 3 C rise in temperature under doubled CO2 situation and pearl millet sustained yield only up to 1C rise in temperature with doubled CO2 level. Except for wheat, active growth phase was found to be the most sensitive growth phase to temperature rise resulting in maximum of 26, 30 and 49 percent reduction in yield of rice, maize and pearl millet, respectively. For wheat it was the grain-filling phase that was found to be most sensitive to temperature rise resulting in 12 percent reduction in yield. ∗ [email protected]