Geographical variation of climate change impact on rice yield in the rice-cropping areas of Northeast China during 1980-2008

Abstract

Northeast China (NEC) is one of China's major rice production areas and has experienced obvious climate warming over the past three decades, similar to other mid- to high-latitude regions in the Northern Hemisphere. The present study investigates the temporal and spatial impacts of climate warming on rice yield in mid-high latitude regions. In this study, two time series datasets of rice yield and climate records in the NEC, including 178 county sites and 105 climate stations and covering the period from 1980 to 2008, were compiled. From these data, the responses of rice yield to the rice-growing season temperature (GST), growing degree days (GDD), and precipitation (GSP) were estimated using a regression model. The results indicate that rice yield benefits from climate warming in the NEC. GST positively impacted rice yield in 64.6% of the counties, with an increase of approximately 3.65%; GDD positively impacted yield in 64% of the counties, an increase of approximately 3.2%; and GSP negatively impacted rice yield in 68% of the counties, with a decrease of approximately 2.3%. Spatial variation was observed in the climate-rice yield relationships. The statistical relationships of GST and GDD with rice yield were significantly and positively correlated with latitude, longitude, and altitude, while that of GSP and rice yield was significantly and negatively correlated with latitude and longitude and showed a nonsignificant positive correlation with altitude. In summary, climate warming has significantly increased rice yield over the last three decades in the region north of 42°N, east of 122.4°E, and at an elevation of 134-473 m, which covers the majority of the rice-growing areas in the NEC.