Study On Resource Utilization And Land Carrying Capacity Of Livestock Manure In Yingshang County

Nitrogen and phosphorus are not only one of the main components of livestock manure,but also essential nutrients of crops.With rapid development of livestock and poultry breeding industry,the amounts of nitrogen and phosphorus of livestock and poultry manure are constantly increasing.The major way to solve the livestock manure is returning it to the field,which not only providing rich nitrogen and phosphorus nutrients for crops but also reducing the application amount of chemical fertilizer..However,excessive return livestock manure to field will cause serious pollution of regional soil,surface water and groundwater.In order to better reveal the characteristics and composition of livestock and poultry breeding and nitrogen and phosphorus pollution in livestock manure,scientific assessment of nitrogen and phosphorus load of livestock manure and livestock breeding capacity in the study area,and used it to optimize the layout of livestock and poultry breeding.taking Yingshang County as an example,the maximum nitrogen and phosphorus load of livestock and poultry manure of cultivated land was estimated based on the principle of nutrient balance,and the bearing capacity and early warning value of cultivated land of livestock and poultry were calculated.Then the spatial analysis method of GIS was used to display the numbers and scale of livestock and poultry breeding farms,,the amount and composition of livestock manure production,the carrying capacity of nitrogen and phosphorus and early warning value in each township of Yingshang County.The main results are as follows:(1)From 2007 to 2019,the annual breeding amount of main livestock and poultry in Yingshang County showed an upward trend.In 2019,the annual breeding amount of main livestock and poultry in Yingshang County was 773600 head(pig equivalent),among which the livestock and poultry production of jiangdianzi Town,Liuji Township,Xieqiao Town and Yanghu Town were in the forefront.Scale farms were mainly distributed in the northwest and northeast of the county.(2)Pigs,beef cattle and laying hens were the main sources of nitrogen and phosphorus pollutants in livestock manure in Yingshang County.The areas with large nitrogen and phosphorus production were mainly distributed in the northeast and northwest of Yingshang County.The average load of nitrogen and phosphorus from livestock manure was 54.90 kg/hm2 and 8.48 kg/hm2 respectively,which were lower than the load standard set by the European Union。The load of nitrogen and phosphorus from livestock manure of each township wasn’t exceeded the load standard value,but some township s were close to the limit standard,and were facing the risk of nitrogen and phosphorus pollution in Yingshang County,for example,Yanghu town and Jiangdianzi town have a large amount of livestock and poultry breeding and a relatively short cultivated land.(3)In terms of pig equivalent,the carrying capacity of nitrogen and phosphorus in livestock and poultry breeding per unit cultivated area in Yingshang County was 8.59head/hm2 and 16.10 head/hm2,and the carrying capacity potential of nitrogen and phosphorus in livestock and poultry breeding per unit cultivated area was 0.48 head/hm2 and 8.8 head/hm2,respectively.According to the standard of nitrogen and phosphorus,there were 13 and 6 townships whose amounts of livestock and poultry breeding exceeds that of bearing capacity of cultivated land,and faced the risk of nitrogen and phosphorus pollution.(4)From the perspective of farmland load warning of livestock and poultry breeding,the nitrogen and phosphorus load warning values of livestock and poultry breeding in Yingshang County in 2019 were 0.94 and 0.45,respectively.The livestock and poultry breeding ecology of the whole county was in polluted and slightly polluted,but the pollution risk of each township was significantly different.In conclusion,there was the risk of livestock manure polluted farmland in Yingshang County,which should be paid more attention to.Among them,townships with high pollution risk or potential risk can reduce the amount of regional livestock manure returned to the field through multiple utilization of livestock and poultry manure;the amount of livestock and poultry breeding should be properly controlled,and the livestock and poultry farming should be moderately developed within the range of carrying capacity of livestock manure of regional cultivated land so as to promote the coordinated and sustainable development of livestock and poultry breeding industry and the environment.