The evolution path of crop structure in the Sanjiang Plain in the 21st century

Analyzing crop structure objectively is important for optimizing and adjusting crop structure, advancing agricultural supply-side reform and realizing agricultural modernization. Based on the remote sensing images of Sanjiang Plain from 2000 to 2015, and applying the GIS spatial analysis and mathematical statistical analysis methods, this paper analyzed the spatial-temporal characteristics and evolution path of the crop structure. Results indicate that: 1) from 2000 to 2015, the planted acreage for corn and rice increased significantly, and the soybean acreage and other crop areas decreased; 2) in the past 15 years, the crop structure in Sanjiang Plain counties changed to single crop variety of rice or corn, and the structure of combination of soybean and other crops changed to the structure of the combination of rice and corn; 3) from the spatial perspective, the single crop structure and the structure of the combination of corn and rice were mainly expanded in the northeast river coast and the low-lying plain counties in the middle, while the structure of the combination of soybean and other crops shrunk to the high-lying mountainous and hilly counties in the northwest and the south; and 4) factors such as natural environment, social and economic conditions, agricultural investment and technological progress affect each other and jointly promote the spatial-temporal change of crop planting area and crop structure in Sanjiang plain. As for the national/regional agricultural supply-side structural reform, Sanjiang Plain needs to reduce the planting scale of corn, to increase the planting scale of soybean appropriately, and to stabilize the planting scale of rice to form a reasonable crop structure.