Abstract:

To scientifically plan the layout of livestock and poultry breeding industry in Xiangtan County and promote the development of integrated planting and breeding circular agriculture, this study is conducted based on the basic data of crop farming and animal husbandry in Xiangtan County in 2021. According to the technical guidelines for calculation of land carrying capacity of livestock and poultry manure and feces, it systematically calculates the total amount of livestock and poultry manure generated in the county, the nutrient supply amount, and the land absorption capacity, and constructs a carrying capacity evaluation system. The results show that in 2021, the total amount of livestock and poultry manure generated in Xiangtan County was equivalent to 499,900 pigs, among which pigs contributed 362,400 pig equivalents, accounting for 72.49%. The excretion amounts of nitrogen and phosphorus nutrients in livestock and poultry manure were 5,499,200 kg and 824,900 kg respectively, and the actual supply amounts after collection and treatment were 3,499,500 kg and 599,900 kg respectively. The 68,547 hectares of cultivated land and 115,347 hectares of crop planting area in the county can carry 2,195,800 pig equivalents, with a carrying capacity index of 0.23. The current breeding scale has not exceeded the land carrying upper limit, and there is a surplus space of 1,695,900 pig equivalents. In terms of spatial distribution, towns such as Zhonglupu Town, Yangjiagqiao Town, and Shitan Town have prominent land absorption capacity, with a potential area of 26,893 hectares for nearby returning to fields. This study clarifies the resource matching characteristics and spatial differentiation law of integrated planting and breeding in Xiangtan County, provides a scientific basis for the regulation of livestock breeding scale, the optimization of planting and breeding layout and the resource utilization of manure in the county, and also provides a reference for the manure treatment and green agricultural development of major grain and pig counties in the southern hilly plain interlaced area.

Key words: livestock and poultry manure, land carrying capacity, assimilative capacity, integrated farming and planting, Xiangtan County