Abstract: Using the ground measurements of crop yield and instrumental climate data during 1950-2014, we studied the responses of crop yield to inter-annual climate variability and to climate change trend within decade. The results demonstrate that inter-annual crop yield variability was positively correlated with precipitation (P) and rainfall days (Rd). There were correlation coefficients of 0.35 (P<0.10) and 0.24 (P<0.10) between wheat yield (Wy) and P and Rd, respectively. The correlation coefficients were all 0.32 (P<0.05) between rice yield (Ry) and P and Rd. However, the inter-annual crop yield variability was negatively correlated with temperature (T) and Potential Evapotranspiration (PE). Between Wy and T, PE, there were correlation coefficients of -0.32 (P<0.05) and -0.41 (P<0.001), respectively; and, for the Ry, the correlation coefficients were -0.26 (P<0.05) and -0.33 (P<0.01), respectively. In the sights of climate change trend within decade, the national mean crop yield exhibited a decreasing trend during 1996-2005, during which the climate changes were characterized by drying and warming trend. Moreover, the spatial variability of crop yield changes was correlated with that of climate changes. The spatial variability of Ry changes was positively correlated with that of P and Rd changes (R=0.24, P<0.001; R=0.11, P<0.05), respectively and were negatively positively correlated with that of T and PE changes (R=-0.13, P<0.01; R=-0.33, P<0.001). The spatial variability of Wy changes was as well as positively correlated with that of P changes (R=0.18, P<0.001) and was negatively correlated with that of PE changes (R=-0.12, P<0.05). Abovementioned findings suggest that moisture is the dominant meteorology factor that determines the variations of crop yield in India. Even though India has developed agriculture irrigation infrastructure, crop yield would be below normal as a response to the climate conditions of less moisture and higher temperature.

Key words: India, rice, wheat, crop yield, climate changes