广东省畜禽粪便时空变化特征及耕地负荷分析

根据广东省统计数据和各种估算参数,以地级市为单位,分析了2000～2008年广东省主要畜禽粪便产生总量及养分总量时空变化特征、单位耕地面积N、P2O5负荷量及其污染风险预警。结果表明,广东省畜禽粪便产生总量约为9 300万t,猪粪、牛粪和鸡粪是主要贡献因子,三者之和占畜禽粪便总产生量的95%以上。广东省畜禽粪便产生量有明显的空间变化特征,表现为:环珠江口城市畜禽粪便产生量相对较低,距离珠江口越远,畜禽粪便产生量越多,其中茂名市和湛江市最多,畜禽粪便年均产生量超过1 000万t,深圳市、中山市和珠海市畜禽粪便年均产生量不到茂名市的4.5%;广东省平均单位耕地面积畜禽粪便N、P2O5负荷量有逐年增加的趋势,但不同地区负荷量差异较大。深圳市、东莞市和佛山市等地负荷量最大,超过300 kg/hm2,而韶关、清远、湛江和中山等市负荷量相对较小;畜禽粪便污染风险评价结果显示,广东省耕地已经受到了不同程度的污染威胁,其中珠江三角洲地区耕地的风险警报级别较高,特别是西江流域地区。因此,广东省特别是污染分析警报级别较高的地级市应该加强畜禽粪便的风险管理、开发利用和综合治理工作。

Analysis on Spatial-temporal Variation Characteristics and Farmland Load of Poultry and Livestock Excrement in Guangdong Province

Based on statistical data and related parameters,the spatial-temporal variation in total amount and nutrient content of poultry and livestock excrement(PLE) and farmland load and pollution risk evaluation of N and P2O5 in PLE were analyzed in Guangdong Province.The results showed that the total amount of PLE was about 9.3 × 1010 kg per year in Guangdong Province.Pig excrement,cow dung and chicken litter are the major contributing factors,95% more of the total amount of PLE.Significant spatial variation of PLE production was found in Guangdong Province,characterized by: cities around the Pearl River Estuary have the lowest production amount of PLE;with the cities away from the Pearl River Estuary,the production amount of PLE becoming more and more.The Maoming City and Zhanjiang City have the most annual production of PLE,more than 10×109 kg per year,while the lowest production amounts were found in Zhuhai,Zhongshan and Shenzhen City,less than 4.5% of the Maoming City.The average farmland load of N,P2O5 in PLE was becoming increase,but various in different cities in Guangdong Province.The Shenzhen,Dongguan and Foshan City have the largest farmland load amount with more than 300 kg/hm2;the farmland load amounts,however,were relatively lower in Zhongshan,Qingyuan,Shaoguan and Zhanjiang City.Results of pollution risk assessment of PLE showed that the farmland was contaminated to different extent by PLE in Guangdong Province.The highest risk alert level was found in Pearl River Delta areas,particularly in the Xijiang River basin area.Therefore,works of enhancing the risk management,development and utilization and Comprehensive treatment of PLE should be carried out in Guangdong Province,especially in cities of higher risk alert levels.