| On the basis of investigations on the number of livestock and cultivation pattern, pollution and environmental risks caused by the development of the livestock and poultry industry were evaluated by means of estimating livestock manure discharge amounts and loads in Shaanxi area, providing a scientific basis for sustainable development of livestock and poultry industry and environmental pollution control. Results showed that the number of poultry was the largest, followed by pig and sheep, among the livestock and poultry breeding in Shaanxi Province. The amount of livestock manure excrements had obviously fluctuated from 2006 to 2010, and was at a low level in 2008, but later became increased rapidly. For the annual amounts of livestock manure excrements, the rank was cattle, pig, sheep, poultry and rabbit. The livestock manure loads showed an increasing tendency, which was increased 70.7% from 10.78 t·hm-2·a-1 in 2008 to 18.4 t·hm-2·a-1 in 2010. The alarm value of livestock manure loads had been increased from the minimal value of 0.36 in 2008 to 0.60 in 2010, and the degree of pollution threat effects on the environment was changed from none to being subtle. In 2010, the total production number of COD and BOD from livestock manure was 121.25×104 t and 104.09×104 t, respectively. Compared with 2008, the discharge of COD, BOD, NH3-N, total nitrogen and total phosphorus from livestock manure in 2010, were increased respectively by 73.2%, 69.4%, 76.7%, 72.6% and 58.2%, respectively. It was estimated that the number of COD, BOD, NH3-N, TN and TP that were leached out from livestock manures into water bodies reached 36.38×104, 31.23×104, 3.44×104, 83.4×104 and 39.85×104 tons in 2010, respectively. |