Cropland disturbance intensity: Plot-scale measurements, multilevel determinants and applications in rural environmental protection

Currently, China is focusing significant efforts to resolve its problems of environmental pollution. For rural environmental protection, it is critical to identify farming practices that pose a negative environmental impact and potential areas with high environmental pollution risk. This study presents a methodology for the development of a novel index, specifically targeted at the assessment of the plot-scale cropland disturbance intensity (CLDI). Different farming practices during each crop management stage that potentially induce both physical and chemical disturbances were systematically evaluated. The rough set method was utilized to avoid subjectivity during weight allocation. Furthermore, an ordered logit model was applied to analyze critical factors that affect CLDI as well as to identify potential areas of rural environmental protection in the mountainous regions of southwestern China. Our results indicate that tillage contributed most to the physical disturbance, and the widespread application of inorganic fertilizers was the main reason for the high level of chemical disturbance. Cropland plots in traditional farming areas received a more intensive physical disturbance. However, for areas where off-farm work is popular and with broad participation in China's Sloping Land Conversion Program, cropland plots suffered from the most intensive chemical disturbance. The model results show that both household and plot level variables significantly influenced the CLDI (R2 = 0.65, P < 0.01). At the household level, critical variables that positively affected the CLDI included the scale of the agricultural laborer, cash income, and cultivated land area per agricultural laborer. The intensity of chemical disturbance increased with increasing off-farm work. At the plot level, distance from the household negatively impacted CLDI, while the distance to the nearest forest posed a positive influence. To achieve a reduction of soil erosion and non-point source pollution control in the study area, we suggest to prioritize cropland plots with a distance radius of 150 and 800 m from households, respectively.