Potential productivity of rice in Sichuan Province in recent five decades

Climate change has significantly influenced agricultural production in Sichuan, a main grain producing region in China. Scientific evaluation of the impact of climate change on rice production is crucial for sustainable development of regional agriculture. In this study, daily meteorological data for the period 1961?2010 from 45 weather stations were collected along with phenological data of rice for the period of 1981?2010 in order to analyze the temporal and spatial distributions of potential productivity of rice in Sichuan. The whole area of Sichuan was divided into 8 regions, including 7 rice growing regions and one non-rice growing region. Photosynthetic potential productivity, light-temperature potential productivity and climate potential productivity of rice in each region were calculated and the corresponding spatial and temporal variations analyzed. The improvements in potential yields of rice were further analyzed by comparison of potential productivity to actual yield. The results showed that while photosynthetic potential productivity was high in the southern Sichuan, it was low in central Sichuan. Light-temperature potential productivity was high in the northern and low in the southern regions. Climate potential productivity was high in central Sichuan and low in the northern and southern regions. Decreasing sunshine hours in the last five decades led to the declines in rice photosynthetic potential productivity since the 1980s. Temperature increase benefited light-temperature potential productivity of rice and the peak value of light-temperature potential productivity was in 2006. Precipitation was one of the main limitations and decreasing precipitation resulted in low climate potential productivity since the 1990s. A significant gap was noted between potential productivity and actual yield and the potential for improving rice yield declined with the decades. There was urgent need to develop science and technology in order to make better use of the climate resources and raise the yield of rice in the study area.