Spatial pattern of cultivated land fragmentation in mainland China: Characteristics, dominant factors, and countermeasures

Systematically recognizing spatial patterns and driving factors of cultivated land fragmentation is of great significance for the exploration of locally appropriate path to relieve cultivated land fragmentation. This study aims to estimate cultivated land density, mean patch size and area-weighted mean shape index to respectively indicate the characteristics of cultivated land fragmentation from three dimensions, namely, natural resource endowment, spatial partition, and convenience of utilization. The regional leading factors of cultivated land fragmentation are also analyzed. The results demonstrate that the distribution of cultivated land density is higher in Northern regions compared with those of southern regions. The significant positive correlation between cultivated land density and mean patch size is found to be universal across nearly all cities, exceeding differences in terrain, elevation, climate, soil, and social economic condition. For cities in the southern part of China, cultivated land of regular shape is partitioned to smaller blocks compared with irregular ones; alternatively, intensive and meticulous farming under small-scale agricultural operation leads to clusters with low mean patch size - low area-weighted mean shape index. Random forest model explains the impact of driving factors on cultivated land fragmentation, with an explanatory power ranging from 66% to 95%. The terrain factor emerges as the primary driver negatively affecting cultivated land density. Gross domestic product emerges as the dominant factor with a significant (p < 0.01) negative correlation to mean patch size for nearly all agricultural climatic zones. Terrain, gross domestic product and population is the most important factor affecting area-weighted mean shape index. Rural development degree influences correlation between dominant factors and cultivated land fragmentation. This study is greatly instructive for recognizing the spatial patterns of cultivated land fragmentation at the national scale and for exploring the barriers that impede regionally scaled cultivated land use.