| Jiangxi Province is one of the main rice producing areas in China.Rice as the main food crop.Encouraging the expansion of rice multiple cropping area is one of the effective ways to increase grain yield.Carry out remote sensing dynamic monitoring of the rice planting system in Jiangxi Province,and analyze the spatial changes of the rice planting system,which is conducive to the rational distribution of agricultural production.This article takes paddy fields in Jiangxi Province as the research object,and carries out the following research work:(1)Based on the GF-1,GF-2 and ZY-3,using ArcGIS software to visually interpret and digitize the vector range of paddy field in Jiangxi Province in 2019,and analyze the spatial distribution characteristics of paddy field in Jiangxi Province;(2)Based on the DEM and 2019 multitemporal Sentinel-1 SAR and Sentinel-2images,the topographic characteristics,spectral band characteristics,vegetation index characteristics,texture characteristics,and backscatter characteristics of rice in different cropping systems were analyzed.The feasibility of remote sensing extraction of rice planting system was discussed;(3)With the support of Google Earth Engine(GEE)cloud platform,the digital elevation model,Sentinel-1 SAR and Sentinel-2 data were used to compare and analyze different classification features.Based on the random forest classification algorithm,the accuracy difference of rice planting systems in Jiangxi Province was extracted and analyzed Spatial distribution of rice in different cropping systems.Research indicates:(1)The The paddy field area of Jiangxi Province is 27503.21 km~2.It shows continuous cluster distribution in the Poyang Lake Plain and Jitai Basin,and it is scattered and fragmented in the mountainous and hilly areas of southern Jiangxi.The paddy field is mainly distributed in areas with elevation from 200 m to 500 m and slopes range from 5°to 20°.The distribution of paddy fields in Jiangxi Province is quite different,the distribution is uneven,and the difference is obvious.The paddy fields are mainly distributed in the area 500 m from the waters and 200 m from the residential areas;(2)There is separability between rice in different planting systems,seasonal changes in the reflectance,vegetation index,and backscatter coefficient of the rice in the multispectral bands of different planting systems are significantly different.The elevation has a significant effect on the extraction of rice planting systems;(3)Based on the optimal feature set obtained from the DEM,Sentinel-1 SAR and Sentinel-2 multi-source data,a random forest classification algorithm was used to extract the rice planting system in Jiangxi Province with an overall accuracy of83.95%and a Kappa coefficient of 0.706;(4)In 2019,double-crop rice in Jiangxi Province accounted for 32.42%of the paddy field area,single-crop rice accounted for 54.16%,and waste was 13.42%.Double-season rice is distributed in the Poyang Lake Plain,Ganfu Plain,and Jitai Basin;single-season rice is distributed in towns,mountains,and hills;and remote mountain paddy fields are abandoned;(5)Rice in different planting systems is mainly distributed in areas with elevation from 0 m to 100 m and slopes range from 0°to 2°.The number of plaques and the average plaque area of different cooked rice were significantly different.Abandoned patches have the fewest number,and the average patch area of single cropping rice is the largest.The smaller the number of paddy fields under different planting systems as a whole decreases with distance from water systems and settlements,various types of paddy fields are basically distributed in areas that are500m from the water system and less than 200 m from the settlements.Paddy field abandonment phenomenon in all counties of Jiangxi Province,the abandonment is more serious in some counties in the east and south,and the abandonment rate is lower in the middle and west. |
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