Suitability evaluation of eco-climatic conditions for high quality rice production in Sichuan Province

This research evaluated ecological and climatic conditions in rice cultivation region of Sichuan Province and analyzed spatial distributions of those conditions in the region. The study aimed to provide a theoretical basis for rice quality improvement through optimization of rice cultivation region. Ecotone-based field experiments in Sichuan, Yunnan, Guizhou and Chongqing were conducted, based on which a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Statistical analysis of weather data and spatial interpolation in Geographic Information System (GIS) were used to study the adaptability of high quality rice to the climate and ecology in rice cultivation zones in Sichuan. Furthermore, the spatial distribution of high quality rice production zones in Sichuan was analyzed. The results showed significant regional specialties for high quality rice production in various rice cultivation zones in Sichuan. Through regression analysis between critical periods of rice growth and certain environmental and climatic factors, a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Besides, meteorological factors which remarkably affected rice growth and quality development were screened in the study areas. Mean daily temperature, percent sunshine, solar radiation and vapor pressure of the 30-day period after full heading stage was regarded as strong evaluation indices of climatic and ecological regionalization of high quality rice cultivation. A comprehensive evaluation model was developed for ecological adaptability of high quality rice in Sichuan rice cultivation zones. Based on the model, ecological and climatic adaptability of high quality rice in each rice cultivation zone in Sichuan were graded and the regional spatial distribution determined. The most suitable regions for high quality rice cultivation were mainly distributed in the northwest periphery of Sichuan Basin, the western and northern regions of the basin and most of the southwest mountain region (except the west part). Besides, odd pieces of land in the southwest and northeast on the periphery of Sichuan Basin were also suitable for high quality rice cultivation. Some areas such as the north and southwest on the periphery of Sichuan Basin, the east and south of the plain region in the west of the basin, the northwest and northeast of the shallow hill region in the center region of the basin, and the west of the mountain region in the southwest were classified as second high quality rice cultivation regions. This study thus provided scientific basis for optimizing the layout and structure of high quality rice production in Sichuan.