Spatiotemporal variation characteristics of livestock manure nutrient in the soil environment of the Yangtze River Delta from 1980 to 2018.

The pollution problem caused by surplus livestock manure nutrient is becoming more and more serious; thus, analyzing characteristics of the temporal and spatial patterns of livestock manure nutrient and assessing the risks are extremely important. The pollution coefficient method was used to figure out the spatiotemporal variation characteristics of the nitrogen (N) and phosphorus (P) emissions of livestock manure nutrient in soil of the Yangtze River Delta from 1980 to 2018. High-risk areas for livestock manure pollution were determined by matching degree assessment between livestock manure nutrient supply and crop nutrient requirements. Clustering and principal component analysis were applied to select main control factors. The results found that the total discharge and manure N and P loads in animal manure nutrient showed an overall trend of increasing first and then decreasing in the Yangtze River Delta in the soil from 1980 to 2018. The center of manure N and P loads shifted from the central region to the northeastern and southwestern regions. There were four typical patterns for manure N emissions, the main control factors were meat production and primary industry. Meanwhile, the main control factors for the four typical patterns of manure P emissions were meat production and cultivated land area. This research provides a theoretical basis for the sustainable development of the livestock breeding industry and is of significance for promoting a balance between planting and breeding in the Yangtze River Delta.