Analysis And Research On The Spatial And Temporal Evolution Of Planting Structure Of Main Food Crops In Three Northeastern Provinces

With the growing population of China,the people's demand for food is also increasing.China is a large agricultural country,and the three eastern provinces are very important grain bases.It is of great significance to understand the spatial distribution of the main grain crop planting structures in the three eastern provinces.With the development of remote sensing technology,the use of remote sensing images to analyze the spatial distribution of crop planting structure is an important symbol of modern agricultural development.In view of this,this paper analyzes the spatial distribution of planting structure in the research area through the MODIS remote sensing data of crop growth and development in the three northeastern provinces in 2000,2005,2010 and 2015.First,preprocess the MODIS remote sensing image,including mosaic,cropping and conversion projection operations,and then use the TIMESAT software to smooth the MODIS-EVI time series data,extract the crop spectral curve,and determine its characteristic value according to the time series curve of different crops.The eigenvalues combined with the crop phenology information,using hierarchical decision tree classification method to identify and extract the planting areas of the main food crops in the three provinces of Northeast China in 2000,2005,2010 and 2015,reveal the characteristics of the spatial pattern changes and qualitatively analyze crop Factors influencing the change of planting structure,put forward suggestions and countermeasures to optimize the layout of planting structure.The main research conclusions are:(1)MODIS remote sensing data image is used as a research data source and is an ideal data source to study crop planting structure in a large area with relatively stable planting structure.In this study,the overall accuracy of extracting crop planting area in the three eastern provinces in 2000,2005,2010 and 2015 reached more than 84%.(2)From 2000 to 2015,the dominant planting species in Heilongjiang Province was corn.The area of soybean-dominated planting areas has undergone an "increasing-decreasing" change process.The planting area of corn and rice has been increasing.Overall,soybean and rice There is a trend of scattered planting,while corn planting is more concentrated.From 2000 to 2015,the dominant planting species in Jilin Province was also corn.The planting area of corn and rice has been increasing,and there is a trend of cluster planting,but the planting area of soybeans is decreasing.From 2000 to 2015,the dominant planting species in Liaoning Province was rice.The planting area of corn has been increasing,but the opposite of soybeans is showing a decreasing trend.The planting area of rice increased from 2000 to 2010,but it showed a decreasing trend from 2010 to 2015.(3)The change of crop planting structure is the result of a combination of factors.Socio-economic factors have a subjective influence on the types of crops farmers choose to grow,natural conditions have an effect on the growth and development of crops,and national policies restrict the planting pattern of crops macroscopically.Therefore,from the perspective of improving crop quality and promoting national beneficial policies,suggestions for optimizing the crop planting structure were put forward.