Trend and spatial pattern of stable cropland productivity in China based on satellite observations (2001-2020)

Sustained productivity growth of China's stable cropland is crucial for meeting the food and nutritional needs of the 1.4 billion population amid global food market volatility, limited uncultivated land, and urban and ecological land squeezing agricultural space. Despite this, research on trend tracking and spatial pattern identifying in productivity of China's stable croplands at a national scale is currently lacking. Here, we attempted to fill this gap based on satellite observation data and cloud computing platform, using the crop growth index, quadratic regression model, and indicator-based spatial overlay analysis. Results show the productivity of China's stable cropland rose by similar to 31.07% from 2001 to 2020 but will fall to similar to 78.89% to similar to 85.78% of the 2015 level (baseline year of SDGs) by 2030. The declining trends can be attributed to three main factors: (1) 69.15% of cropland that previously exhibited significant productivity growth has started to decline; (2) the productivity of cropland with the highest agricultural suitability (Level 4-5) has been long-term declining, showing no signs of reversing; (3) 44.12% of stable cropland's productivity was volatile over the research period, leading to high uncertainty in productivity growth. The large-scale spatial overlap between high agricultural suitability and human activity intensity determined the spatial pattern of stable cropland productivity. Therefore, comprehending and mitigating urbanization's indirect and off-site detrimental impacts on cropland productivity are critical to ensuring China's future food security.