施用有机物料土壤中氮、磷及重金属的短期淋失规律

Short-term Leaching Dynamics of Nitrogen,Phosphorous,and Heavy Metals after Additions of Organic Materials into Soil

通过土柱培养试验,研究土壤中氮、磷、重金属在污泥堆肥、猪粪堆肥土地利用后30天内的淋失规律。研究发现,混合土层与土壤底层中硝氮及磷酸盐在添加有机物料后30天内不断溶出,而氨氮在有机物料施用后的5～10天内溶出风险最大;有机物料的施入显著提高了土壤中重金属Cu和Zn的水溶性,混合土层Cu、Zn的淋失含量分别在施用有机物料后第2天与第5天达到峰值,并逐渐向下迁移,使土壤底层Cu的溶出量逐渐升高,Zn的溶出量在5～10天达到最高,其中污泥堆肥处理最明显。土壤溶解性有机碳含量也在施用有机物料后短期内有明显的增加,并显著影响土壤中氮、磷、重金属的短期淋失量。以上结果表明,土壤中氮、磷、重金属在施用有机物料后短时间内就有淋失风险,对地下水造成较大威胁。因此,应该特别关注有机物料土地利用后污染物在短期内的排放及其控制措施,减轻对土壤生态系统的短期冲击,减少对环境污染的风险。

Using the soil column device,this paper studied the short-term leaching dynamics of nitrogen,phosphorous,and heavy metals after additions of sewage sludge compost and swine manure compost into the soil.The contents of nitrate nitrogen and phosphate in soil solution of mixed soil layer and subsoil increased in short-term after applications of organic materials.Ammonia nitrogen in soil had the largest leaching risk during 5～10 days after nutrients input.The contents of Cu and Zn in leachate of mixed soil layer reached the peaks on the second and the fifth days,respectively.The leaching concentrations of Cu in subsoil increased,especially in sludge compost amended soil.Zn in subsoil solution reached the higher values during 5～10 days after nutrients input.These results showed application of organic materials resulted in the short-term leaching risks of nitrogen,phosphorous,and heavy metals in soil,which may pose the threat to ground water.The increase of dissolved organic carbon in soil solution was also observed in short term after organic materials inputs,and significantly influenced the leaching of N,P and heavy metals.The higher contents of nutrients in organic materials might evoke reproduction of microorganism in soil,accelerate decomposition process,and produce abundant of dissolved organic matter,which could promote the transformation and movement of pollutants.Therefore,the short-term risks of pollutant leaching after addition of organic fertilizers are needed special attentions.The control measures were demanded to develop in order to reduce the short-term impulse on soil ecosystem and decrease the risk on environment.