| As urbanization processing,population increasing,social economy developing and the demand for animal products growing,the animal husbandry not only promotes the commercialization of animal production with large-scale and industrialization,but also change the mode of traditional agriculture and animal husbandry,and if the livestock manure will not get effective use,it is bound to cause environment pollution.On the other hand,the unreasonable agricultural irrigation will lead to soil erosion,the inappropriate utilizational of chemical fertilizer to soil organic reduction,the organic fertilizer to retrogradely purchased and livestock farm out-migration to aggravate environmental pollution in economically backward regions in livestock restricted area.It is an important national issue that the changes of livestock manure from resources into wastes and pollutants,the rational use of manure and urine resources,and the promotion of combination and recycling of agriculture and animal husbandry.The grass-herbivore-fertilizer circulation system is a global sustainable production model of ruminant livestock such as dairy cows,beef cattle,and sheep,and monogastric herbivore such as horses,donkeys,mules,and rabbits.This experiment starts with the evaluation of manure treatment system in large-scale dairy farms,the water quality survey for the surrounding runoff,drains and groundwater to analyze the environmental status after sewage treatment and resource recycling,and provides data support and classics for the resource recycling for livestock farm waste case.1.Evaluation of sewage treatment system in cow farmThe purpose of this experiment was to evaluate the sewage treatment effect of the dairy farm by monitoring the water quality,the discharge of greenhouse gases and the outlet in farm.The inlet and drainage of sewage treatment system in the dairy farm were measured continuously for 5 days.According to the principle of sampling at least 3 cycles for each drainage outlet,the water quality was sampled at least 3 times every 20 days at each sampling point,and the accumulative measurement was conducted for 14 days.Meanwhile,the influence of rainfall on the water quality of each drainage outlet was investigated.Three gas sampling points were set above the three A pools in the sewage treatment system and measured continuously for 7 days.Dissolved oxygen,water temperature,ammonia nitrogen,pH,nitrate nitrogen,chloride,rainfall time,carbon dioxide,carbon monoxide,nitrous oxide,and ammonia were measured.The results showed that:(1)the dissolved oxygen increased by about 3.2 times,the removal rate of ammonia nitrogen exceeded 97%,the removal rate of nitrate nitrogen increased by about 93 times,and the removal rate of chloride was about 30%.(2)The emissions of carbon dioxide and ammonia in the three A pools were far lower than the air health standards of the livestock houses,and there was no significant difference in the same index between the three observation points(P>0.05).Carbon monoxide exceeded the ambient air quality standard,and there was no significant difference between the three observation points(P>0.05).(3)cattle field drain:compared with sewage treatment system drainage,the dissolved oxygen decreased by about 23%,the ammonia nitrogen decreased by about 76%,the nitrate nitrogen decreased by about 76%,the chloride decreased by 65%,and the rainfall had dilution effect.However,chloride is about 2 times higher than the "surface water quality standard",and nitrate nitrogen is 8-18 times higher than the standard,which requires subsequent treatment.2.The recycling system of swage-forest-grass-field,and water quality monitoring in XuhuanxiThe monitoring content of the chloride and nitrate nitrogen in the sewage from the cow farm was still unable to meet the "surface water quality standard",so the sewage from the farm outlet was promoted to the mountain for flood irrigation.By means of Google satellite map 3 d,analyzed the results of dairy reservoir on surrounding trees and grass irrigation access to the paddy fields and ponds,and other surrounding geographical environment,and further determined two outlets linked to Xuhuanxi drain,according to the principle of each port sampling at least 3 cycles,each 20 days each sampling point sampling at least three times for 14 days.Meanwhile,the water quality of upstream and downstream of Xuhuanxi was measured for 14 days.Measured dissolved oxygen,water temperature,ammonia nitrogen,pH,nitrate nitrogen,chloride and rainfall time.Results showed that:(1)water outlet of paddy field:all indexes met the provisions of "surface water quality standard",and the paddy field upstream played a role of water purification.(2)The ponds drain:dissolved oxygen in discharge water was low,other water quality evaluation indexes met the "surface water quality standard",rainfall increased the water pollutants,but did not exceed the standards specified in the surface water.The monitoring data of the upstream and downstream drainage outlets of paddy fields and reservoirs in Xuhuanxi showed that the indicators met the "surface water quality standard",and low ammonia nitrogen drainage in paddy fields and low nitrate nitrogen drainage in reservoirs had a dilution effect on Xuhuanxi,but the water flow with increased chloride concentration and low dissolved oxygen input had little influence on the dissolved oxygen in the stream because of the two drainage outlets through a section of natural wetlands into the stream.In conclusion,under the condition of maintaining the REDOX capacity of Xuhuanxi with high dissolved oxygen content,the effluent from the cattle farm can be discharged through the natural purification of woodland,pasture,paddy field,pond and natural wetland,and further meet the standard.3.Groundwater Monitoring in cow farmIn order to investigate whether the wastewater from dairy farms flooded to the surrounding trees and grasslands will affect the ground water,the groundwater quality of dairy farms will be monitored.The study was conducted at the groundwater concentrations sites of 4 shallow machine Wells scattered around the dairy farm,and samples were collected at least 3 times every 20 days according to the sampling principle at least 3 times every 20 days.Measurement indicators:dissolved oxygen,water temperature,ammonia nitrogen,pH,nitrate nitrogen,chloride.The results showed that the ammonia nitrogen,nitrate nitrogen,chloride and other indicators in the groundwater in dairy farm reached the"Groundwater Quality Standard".The animal feces and sewage from the surveyed dairy farm and the mountain runoff flooding did not affect the groundwater in the area.The groundwater pH exceeds the standard,and mainly relates to the acid rain and soil type in the area. |
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