| China’s livestock and poultry breeding industry have been developed rapidly since the reform and opening-up and the pattern of breeding changed from decentralized to centralize. The feedstaff for livestock and poultry transformed from natural foods to synthesis and additive foods. The livestock and poultry breeding industry can provide abundant and high quality products to the market, meanwhile, quite a number of pollutants also can be discarged from livestock and poultry farm. The pollutants from farm are harmful to environment unless they are treatented properly. Based above opinion, the disposal and management on excrement has become the emphasis focused in preventing rural non-point pollution.In this research, a typical dairy cow farm with500cows, which located in Mashan, Taihu district, were chosen as the objective for study. A source intensity method was adopted to monitor the seasonal feed intake and excretion output of adult and youth cows in winter, spring, summer and autumn. Samples from youth and milk cow waste and sewage were collected and analysed during cow’s different growth stage, meanwhile, samples from indoor and outdoor air were collected and the airborne bacteria, Escherichia coli in livestock house air were measured. The contents of nitrogen, phosphorus and oxytetracycline (OTC) in different soil layers were analyzed, and the runoff fluxes of nitrogen and phosphorus were monitored and estimated within the cow farm field. Grass buffer strips were designed to control the nitrogen and phosphorus loss in rain runoff. The purpose of this experiment was to provide scientific data for dairy waste pollution reduction and control.The main results are showed as follows:1. The emissions of feces and urines and emissions of nitrogen and phosphorus:the annual average feces and urine excretions from an adult cow were11.66and7.62tons, respectively, and they were4.94and2.77tons for a youth cow, respectively. The annual average nitrogen and phosphorus output of an adult cow were99.83and19.71kg, respectively. The annual average nitrogen and phosphorus output of a youth cow were34.92and6.52kg, respectively. The annual amounts of an adult cow feces and urine were significantly larger than that of a youth cow. The feces and urines excretion of cow in cow playground accounted for30%in summer and10%in winter of annual excretion volume, respectively.2. Concentrations of airborne bacteria and E.coli in indoor air of cow house (10m,20m,50m and100m) were relatively higher than those in outdoor air of cow house. When the air is disturbed, the concentrations of airborne bacteria, E. coli were higher than concentrations with and without cows.3. With long-term discharge of cow feces on cow playground, mass phosphorous and nitrogen was accumulated on the soil surface layer, and the leaching of nitrogen, phosphorus, organic matter and oxytetracycline (OTC) downwards with rain appeared. The contents of organic matter, total nitrogen, total phosphorus, available phosphorus, ammonium, nitrate and available potassium in0-40cm soil layer were higher than that of control blank. The residues of oxytetracycline (OTC) were found in0-40cm soil layer. The average residues in0-10cm,10-20cm and20-40cm layers were0.5993mg/kg,0.7849mg/kg and0.7281mg/kg, respectively. The results showed that the contents of OTC appeared increased firstly and decreased afterwards.4. The rain runoff from playground was collected on May until September in2009, and the runoff fluxes of nitrogen and phosphorus were14.95kg/hm2and3.88kg/hm2respectively. The average filtering efficiency of grass buffer strips on runoff nitrogen and phosphorus were65.92%and50.13%, respectively. The average filtering efficiency of grass buffer strips on particulate nitrogen and phosphorus wer81.66%and64.79%, respectively. |
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