Spatiotemporal changes and driving forces of main grain crop planting types in Northeast China from 2017 to 2021

Abstract

[Objective] Northeast China, with its unique resources advantages, provides one-third of China’s commodity grain, making it a crucial part of national food security. Analyzing the spatial distribution, spatiotemporal evolution, and driving forces of grain crop cover types and cropping patterns in Northeast China is crucial for preserving the region’s “black soil granary”. [Methods] Based on Google Earth Engine (GEE), this study integrated existing crop cover type product from 2017 to 2019 with remote sensing extraction results of major grain crops from 2019 to 2021, analyzed the spatiotemporal change characteristics of grain crop planting types and cropping patterns, then revealed the driving forces by using geodetector. [Results] (1) Using phenological information, a multi-feature random forest classification method was employed to effectively extract three major grain crops: maize, soybean, and rice. In 2019, a high Kappa coefficient of 0.908 was achieved, indicating high classification accuracy and consistency in terms of area. (2) In the past five years, the shifting of grain crops from soybeans to maize has been the dominant trend in Northeast China. The shift types include soybean to maize to maize, soybean to soybean to maize, and maize to maize to soybean, accounting for 29.4%, 24.9%, and 19.1% of the total transition area, respectively. The cropping patterns of grain crops in Northeast China exhibit high spatial heterogeneity, with the maize continuous cropping pattern, rice continuous cropping pattern, and soybean-maize continuous-preference rotation pattern accounted for 46.2 %, 23.5 %, and 13.2 % of the total cropping patterns area, respectively. (3) The spatiotemporal dynamics of cropping patterns was significantly driven by natural and anthropogenic factors. Elevation, topographic wetness index, slope, rice price fluctuation, and soybean price fluctuation were important single factors that explain the spatiotemporal changes of cropping patterns. The interactive explanatory power of elevation, active accumulated temperature slope, and economic policy factors was high, and in descending order from elevation∩soybean subsidy variation, elevation∩active accumulated temperature slope, elevation∩fertilization cost variation, elevation∩rice subsidy variation, to elevation∩maize price variation. [Conclusion] During the period from 2017 to 2021, there was a notable shift in the major grain crop cover types in Northeast China, characterized by a transition from soybean to maize, while rice cultivation remained consistent. The spatial distribution of different cropping patterns was influenced by a combination of factors including topography, economy, and policy.

Keywords

• |crop cover type|spatiotemporal dynamic|cropping pattern|driving factor|northeast china