Investigation On Pollution Status Of Pig Breeding Industry In Mingshan District Of Ya'an And Preliminary Exploration Of Ecological Strategy For Pollution Control

With the development of pig product industry and the improvement of intensive level in China,the rapid increase of excrement result in a serious impact on the ecological environment,and cause environmental pollution.Among the many models of excrement treatment and resource utilization,composting combined with planting and breeding is a simple and effective way.Mingshan District is a concentrated area for pig breeding,which has a high proportion in animal husbandry and is also a tea planting base in Ya'an.However,in recent years,there has been a lack of effective data on pig stocks,slaughter,the degree of intensive cultivation development and the cases of production and disposal of excrement in various towns in Mingshan District,as well as the area and output of tea planting.And there is no scientific basis for the tea planting industry to be able to achieve the use of excrement from pig product industry.Therefore,there is no basis for the formulation and implementation of the manure treatment mode and utilization plan.In order to reduce the damage to the ecological environment caused by the pig manure in Mingshan District,improve the utilization level of manure in situ,and establish a suitable mode for the treatment and resources utilization of pig excrement,this paper collects a lot of data of pig production,pig excrement pollution and tea planting from the agricultural management departments of various towns and townships,and according to the field survey of 20% sampling,analyses the balance between production and utilization of pig excrement in various towns in Mingshan.At the same time,the experiment of " excrement treatment + tea planting",that is,“ excrement treatment and resource utilization”was carried out to evaluate the feasibility through tea yield and tea production efficiency.The survey and test results show that:(1)230,000 pigs were kept in Mingshan District in 2017,and 169,800 tons of pig excrement and 280,200 tons of urine were produced.The contents of nitrogen,phosphorus and potassium in the discharge of pig manure were 1575 tons,225 tons and 675 tons,respectively.(2)In 2017,tea planting area was 299,255 acres and tea output was 51 0,000,00 kg in Mingshan District,In theory,the demand for nitrogen,phosphorus and potassium was 4,490 tons,1,497 tons and 1,497 tons respectively.(3)Comparison of the amount of nitrogen,phosphorus and potassium produced by manure in various towns and the demand in tea planting,the demand for nitrogen,phosphorus and potassium in most townships such as Mengyang Town and Mengdingshan Town is much larger than the emission of pig breeding,and the pig breeding output in Zhongfeng Town is greater than the demand for tea planting.There is an imbalance between the production of pig excrement and the demand for tea cultivation in the towns of Mingshan District.(4)The results of “excrement treatment + tea planting” experiment showed that the combination of chemical fertilizer and pig manure could significantly increase the yield of tea(P<0.05),but the organic matter,total organic carbon(TOC)and nitrogen(TON)in soil decreased significantly(P < 0.05),the application of pig manure could significantly increase tea leaf extract and tea polyphenols(P<0.05).The results showed that the combined application of pig manure and chemical fertilizer could improve tea yield,tea quality and soil structure.The investigation and analysis show that the density of pigs is high in Mingshan district,but the excrement form pig product industry can still be fully absorbed by the tea planting industry.However,there is an imbalance between the production and utilization of manure in different townships.So adjust the scale of the pig breeding and tea planting industry in various towns,scientific layout,seed-culture combination,coordinated development.“Excrement treatment + tea planting”experiment results show that The use of pig excrement compost improves the quality and yield of tea and soil fertility,but the full use of organic fertilizer has a negative impact on the growth and yield of tea.In general,the manure produced by the pig breeding industry cannot fully meet the needs of the tea planting industry.The combination of pig manure composting and chemical fertilizers is used to increase the utilization of manure resources and ensure the output and quality of tea.Actively promote the coordinated and sustainable development of pig farming and tea cultivation cycle ecology.