SPATIAL-TEMPORAL DYNAMICS OF SOYBEAN AREA RECOVERY IN HEILONGJIANG PROVINCE IN RECENT YEARS(2016-2020)UNDER THE SUPPORT OF AGRICULTURAL POLICIES
Heilongjiang province is the leading food production region in China.To cope with the impact of soybean imports in recent years leading to a sharp decline in soybean cultivation within the province,and to enhance soybean self-sufficiency,the change in cultivation structure driven by the increase in soybeans occurred in the province under the support of several national policies.And understanding the patterns and processes of crop structural changes can provide important information to support agricultural planning and enhance food security.To comprehensively diagnose the dynamic changes of planting structure,we first mapped the spatial distribution of main food crops(soybeans,corn and rice)in 2016 and 2020 of Heilongjiang province based on remote sensing.Secondly,we calculated the area planted by each crop and the transformation between crops by the transformation matrix,and spatially diagnosed the hot spots of the transformation.Then,we also evaluated the patterns and processes of crop conversion through a multi-dimensional moving window.The results were showed as follows.(1)The overall accuracy of crop mapping in 2016 and 2020 was 89%and 94%.(2)From 2016 to 2020,the soybean planting area in Heilongjiang province increased from 3.5 million hectares to 4.3 million hectares,an increase of 23%,concentrated in the soybean high-yield area in the northeast of the Songnen Plain,which was reflected in the conversion of concentrated continuous pieces of corn into soybeans;(3)The area of corn and rice showed a slight downward trend,and performed an irregular and more discrete distribution.In summary,under the influence of relevant policies,Heilongjiang soybean planting achieves a certain degree of recovery,and the soybean self-sufficiency rate is significantly improved,especially the increase in soybean planting in high-yielding soybean areas enhances feed security and food security,realizes the rational allocation of agricultural resources,and promotes sustainable agricultural development.
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