Recent trends of a decline or stagnation in the yield of rice and wheat in rice-wheat (RW) systems of the Indo-Gangetic Plains (IGP) have raised serious concerns about the regional food security. The effect of future climate change on crop production adds to this complex problem. The validated CSM-CERES-Rice and CSM-CERES-Wheat (Ver. 4.0) data were used to test the sensitivity of the models in Punjab, India. The models were sensitive to climatic parameters (temperature, CO2 concentration, solar radiation and rainfall) on yields of both crops. Simulated rice yields were sensitive to weather as there was 13% less yield of rice in 1999 than in 2001. Similarly, simulated wheat yields were also sensitive to weather, with the highest yield in 2001, and the lowest in 2003. Increments in both maximum and minimum temperatures by 4°C, decreased rice yield by 34% and wheat yield by 4% as compared to base scenario with current weather data. By increasing 4°C for both maximum and minimum temperature along with an increase in solar radiation by 1MJ/m2/day, rice yield decreased by 32% as compared to base scenario while wheat yields were not affected. With the increase in maximum and minimum temperatures by 4°C, and also an increase in CO2 concentration by 20 ppm from the standard CO2 concentration of 335 ppm, the reduction in rice yield was 33%, but in wheat yield was only 3%. Rainfed wheat yield increased by 7%, by increasing daily rainfall by 1.5 times, and by 13%, by doubling the rainfall, both after 96 days of sowing (DAS) to maturity. Lowering rainfall to zero, for each day after 96 DAS to until maturity reduced wheat yield by 18%. The increasing maximum and minimum temperatures irrespective of whether the CO2 concentration increased or not, seemed to have more adverse effects on rice than to wheat. Simulations demonstrated that CSM-CERES-Rice and CSM-CERES- Wheat are sensitive to CO2 and climatic parameters, and can be used to study the impact of future climate change on rice and wheat productivity in RW systems in Asia.
Key words: CSM-CERES-Rice, CSM-CERES-Wheat, climate change, yield, phenology
J. Inst. Agric. Anim. Sci. 27:103-110 (2006)
Future climate change significantly alters interannual wheat yield variability over half of harvested areas
