Prediction Of Future Rice Planting Suitability In My Country Based On MaxEnt Mode

Rice is a major grain crop in China,thus,research on the suitability of rice planting plays an important role in improving rice production layout,increasing yield,and enhancing its adaptability under the background of climate change.In this study,the single rice and double rice were selected as the research objects.Based on historical periods(1971-2000)and the two future periods of 2021-2040 and 2041-2060 under the medium emission scenario(SSP2-4.5)and high emission scenario(SSP5-8.5)of four future climate models,climate,soil and terrain factors were selected as the environmental indicators which affecting rice planting distribution.Based on principal component analysis,Pearson correlation analysis,the maximum entropy model(MaxEnt)and geoinformation spatial technique,the dominant environmental variable factors affecting the distribution of single and double rice planting were determined.The MaxEnt model was used to simulate the potential distribution of planting suitability for single and double rice in the historical period,and to predict the distribution,changes and migration trends of planting suitability for single and double rice under the background of climate change in China.The research results provide reference for optimizing the local agricultural structure adjustment and layout,as well as addressing climate change.The main results are as follows:(1)The six dominant environmental factors affecting the suitability distribution of single rice planting in China are annual precipitation,elevation,mean diurnal range,precipitation of driest season,slope and mean temperature of coldest season.The potential suitable areas for single rice in China during the historical period and in the future are mainly distributed in Northeast,North China,East China,Central China,South China,Southwest,and some northwest regions of China.Based on the probability of existence corresponding to each level,the unsuitable areas and low,medium,and high suitable areas for single rice in China have been determined.Under the background of future warming,the unsuitable areas and low suitable areas for single rice in China are generally decreasing,but the medium and high suitability areas show an increasing trend.In the future,the new suitable areas for single rice in China will mainly be distributed in the eastern,central,and western regions of Inner Mongolia,and some areas in southeastern Tibet.The loss of suitable areas will be scattered in the western and northern parts of Sichuan,the southeastern edge of Tibet,southeastern Gansu,southeastern Qinghai,northeastern Guangxi,southeastern Guangdong,and at the border between Zhejiang and Fujian.Compared to historical periods,the center points of low,medium,and high suitability areas for single rice in China show east-north migration trends in in the future.(2)The five dominant environmental factors affecting the suitability distribution of double rice planting in China are maximum temperature of warmest month,annual precipitation,mean temperature of coldest season,slope,mean diurnal range.The potential suitable areas for double rice in China during the historical period and in the future are mainly concentrated in South China,East China,the southern part of Central China and some southwestern China.Based on the probability of existence corresponding to each level,the unsuitable areas and low,medium,and high suitable areas for double rice in China have been determined.Under the background of future warming,unsuitable areas for double rice in China are decreasing,while low,medium,and high suitable areas are all increasing,and the increase trends of low and high suitable areas are obvious.In the future,the new suitable areas for double rice in China will mainly be distributed in eastern Henan,the border between northern Hubei and Henan,northern Anhui,Jiangsu,eastern Sichuan,and Xinjiang,with almost no loss of suitable areas.Compared to historical periods,the center points of low,medium,and high suitability areas for double rice in China will migrate in the direction of west to north,north to west and west to north in the future,respectively.(3)In different future climate scenarios,the change range and migration trend of the suitable area for SSP2-4.5 and SSP5-8.5 scenarios from 2041 to 2060 are more significant compared to 2021 to 2040,and are more prominent in SSP5-8.5 scenarios.