Liu YAQUN, Key Laboratory of Regional Sustainable Development Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, China
Grain planting of cropland provides essential food and ecosystem services for human survival and development, and is crucial to food security and sustainable socio-ecological system development. Northeast China is one of the most important grain bases, producing 1/4 of national grain and 1/3 of commercial grain. However, in recent years, Northeast China has faced problems such as population outflow, climate warming and drying, and black soil degradation. Thus, revealing the patterns, drivers, and impacts of grain planting in Northeast China is crucial for sustainable development. To this end, based on the GEE platform and MOD09A1 time-series, the feature optimization and random forest algorithms were used to map the annual distribution of major grain crops in Northeast China from 2000-2021. The change characteristics of spatiotemporal patterns, the natural-human driving mechanism, and the carbon-water-yield impacts were revealed to propose policy recommendations for sustainable agricultural development. The results showed that the sample test accuracy of remote-sensing-based crop classification exceeded 85%, and the R2 of the city-level statistics exceeded 0.85. From 2000-2021, the cropland expanded by 3%, corn and rice expanded by 131% and 137% respectively, and soybean reduced by 71%. The proportion of corn and rice increased from 29% and 7% to 65% and 17% respectively, and that of soybean decreased from 58% to 16%. Grain planting changes in Northeast China were jointly affected by economic benefits, policy subsidies and climate changes. Although these changes have improved crop yield and photosynthetic carbon sequestration, they have also increased crop water consumption and carbon footprint, which was not conducive to sustainable agriculture development. Therefore, the crop planting structure and system should be optimized, and the water and carbon use efficiency of crops should be improved to ensure food-ecological security and sustainable development.
Mots clés : Grain planting structure|Patterns-Drivers-Impacts|Google Earth Engine|Northeast China|Sustainable agriculture management
A105014LY