养殖污水灌溉对蔬菜地土壤质量和蔬菜品质的影响

Effects of Long-term Irrigation of Livestock Farm Wastewater on Soil Quality and Vegetable Quality in Vegatable Soils

为了解畜禽养殖污水灌溉对蔬菜地土壤质量和蔬菜品质的影响,在浙江省绍兴县选择了养殖污水不同灌溉年限(0,4,12,23年)的蔬菜地,比较研究了养殖污水灌溉对蔬菜地土壤有机碳、氮、磷、钾、重金属积累和酶活性的影响,探讨了灌溉蔬菜地大白菜中重金属、硝酸盐、蛋白质、维生素C(Vc)和糖含量等的状况。结果表明,长期养殖污水灌溉可明显提高蔬菜地表层土壤(0-20cm)pH、有机C、全N、全P、NH4+-N、NO3--N、有效P和有效K的含量,增加土壤中Cu、Zn和Cd的积累和水溶性Cu、Zn和Cd含量,但对土壤K、Pb、Ni、Cr和Hg的含量影响不明显。长期养殖污水灌溉增加了土壤中脱氢酶、蛋白酶、脲酶、纤维素酶和酸性磷酸酶的活性,增加了大白菜中Cu、Zn和Cd元素的积累和可溶性总糖、P的含量;但养殖污水灌溉不会引起大白菜中粗蛋白、Vc和NO3--N的显著变化。总体上,在研究的灌溉年限内,养殖污水灌溉还没有引起土壤和蔬菜中有害物质的超标,但存在着铜、锌等重金属积累的潜在风险。

Four vegetable fields with different history of livestock farm wastewater irrigation（0,4,12,23 years）were selected for collecting surface soil samples to study the effects of long-term irrigation of livestock farm wastewater on soil quality and vegetable quality.pH value,and concentrations of organic C,total N,total P,total K,NH＋4-N,NO-3-N,available P,available K,heavy metals（Cu,Zn,Pb,Cd,As,Hg,Cr and Ni） and enzyme activity in the soils were characterized.Contents of Vc,crude protein,sugar,NO-3-N,total P,total K,and heavy metals in Chinese cabbage grown in the fields were measured.The results showed that long-term irrigation of livestock farm wastewater increased significantly soil pH value and concentrations of organic C,total N,total P,NH＋4-N,NO-3-N,available P,available K,and both total and water-soluble Cu,Zn,and Cd in surface soil of vegetable lands.However,the irrigation had no significant effects on soil total K,Pb,Ni,Cr,As and Hg.The irrigation also increased activities of dehydrogenase,protease,urease,cellulose,and acid phosphomonoesterase in the soils,and concentrations of sugar,P,Cu,Zn,and Cd in Chinese cabbage.No significant effects of the irrigation on crude protein,Vc,and NO-3-N in Chinese cabbage were found.In summary,the 23 years-irrigation of livestock farm wastewater to vegetable fields did not cause severe pollution,the concentrations of heavy metals in soil and vegetable crops in all vegetable fields were within the upper limits of national environmental criterions.But accumulation of Cu,Zn,and Cd in both soil and vegetable crops indicated that there was pollution risk of long-term irrigation of livestock farm wastewater.