Assessment and Effect of Mining Subsidence on Farmland in Coal-Crop Overlapped Areas: A Case of Shandong Province, China

Farmland protection and food security is highly focused on in China. However, coal mining has caused negative consequences to cropland in coal-crop overlapped areas (COA), especially in eastern China. Thus, revealing the spatiotemporal impact of coal mining on farmland on a large scale is crucial for coordinating coal mining and grainland protection. In this study, Shandong Province, a representative coal-grain composite area, was selected as a research case to evaluate the damage of mining subsidence on farmland. Firstly, the field investigation and mining subsidence prediction revealed the current situation and trend of farmland damage caused by mining in 2021 and 2030. Then, we evaluated the impact of cropland damage on grain yield. Finally, farmland landscape patterns, ecological environment, and social stability due to mining subsidence were discussed. The results show that: (1) the damaged cropland in 2021 was 6.40 x 10(4) ha, of which 1.40 x 10(4) ha was non-yield. By 2030, the accumulative area of damaged cropland is estimated to reach 7.52 x 10(4) ha. (2) By 2025 and 2030, the farmland yield will be reduced by 16.44 x 10(4) t and 18.45 x 10(4) t in overlapped areas of Shandong. (3) The subsidence led to cropland fragmentation, and the terrestrial ecosystem became an aquatic ecosystem, further intensifying the contradiction between more people and less land. This study provides a reference for coordinating coal and grain production and formulating cropland protection strategies in similar regions. Meanwhile, it also provides a scientific basis for the government to formulate land reclamation indicators, technology, management, and acceptance standards and establish and implement the reclamation reward and punishment system.