Characteristic distribution of livestock manure and warning analysis of environmental carrying capacity based on the consumption of cultivated land in China

In order to speed up the utilization of excrement and waste resources in the livestock and poultry breeding industry, and to promote the sustainable development of animal husbandry, it is particularly important to timely grasp the characteristic distribution of excrement and waste for effectively preventing and controlling environmental pollution in the breeding area. At present, most of the researches focus on livestock and poultry feces pollution, based on the level of provinces and cities, while the researches on the national scale are relatively few. In this paper, manure production, pollutant production and pollutant loss in the livestock and poultry industry in 2016 were estimated with the pollution factor method and based on the calculation of China Animal Husbandry Yearbook data. The pig feces equivalent bearing load and early warning, and the value per unit cultivated land area were calculated on the basis of the above analysis and by converting feces and urine produced by different kinds of livestock into pig feces equivalent. Furthermore, the corresponding early warning level of 31 provinces in 2016 was obtained by referring to relevant standards. The results showed that in 2016, the total amount of livestock and poultry manure was 2 468 million tons, of which cattle manure was the most and poultry manure was the least; among the 31 provinces studied, Sichuan Province, Henan Province and Shandong Province had relatively more manure. Assuming that the manure could be effectively consumed by the farmland in the same year, the bearing capacity load of pig feces equivalent per unit cultivated area in 2016 was 19.55; and the early warning value of pig feces equivalent per unit cultivated area was 0.49. Most of the 31 provinces measured in this paper were at level Ⅰ, among which Beijing was at level Ⅲ, Tibet was at level Ⅵ, and Qinghai was at level Ⅴ. According to the result of early warning level, each province should make full use of the livestock and poultry manure according to its own situation. Timely control of the total amount of livestock and poultry breeding, and pollution prevention and control measures should be taken in areas with high early warning value.