城市污泥施用对喀斯特石漠化土壤质量的改善

Effects of Municipal Sewage Sludge Addition on Soil Quality in a Rocky Desertification Area

为研究城市污泥施用对喀斯特地区石漠化土壤质量的改良效果,以石漠化土壤和城市污泥为试验材料,采用模拟土壤熟化试验,分析了20%~75%比例的污泥添加对土壤持水性能、养分、重金属含量及微生物生物量的影响。结果表明:随着污泥用量的增加,土壤饱和含水率增加了22.04%~67.07%,持水时间延长了5.19~16.25 d;土壤有机碳、氮、磷含量及微生物生物量也显著增加。但土壤微生物生物量不是随污泥施用比例的增加而增加,在污泥施用比例为20%~35%范围内,土壤微生物生物量显著高于高比例的污泥添加。50%~75%的污泥施用还导致Cd和Zn超过土壤质量标准。因此,适量的城市污泥施用可改善土壤持水性能、提高土壤肥力,以20%~35%比例为宜。

In order to assess the impact of municipal sewage sludge(MSS) on soil quality in Karst rocky desertification regions,a simulated soil ripening experiment was conducted,in which soil sampled in a rocky desertification region and MSS collected from a domestic sewage treatment plant were the test materials.Soil water-holding capacity,nutrient content and soil microbial biomass were analyzed in soils added with 20% to 75% of MSS.The results showed that,as the addition rate of MSS increased,saturated water content of soil increased by 22.04%-67.07%,the water-holding time prolonged 5.19-16.25 days,and soil organic carbon,nitrogen,phosphorus and microbial biomass increased significantly.However,the increase of soil microbial biomass was not proportional to the application dosage of MSS.Soil microbial biomass were obviously higher in soils with 20%-35% MSS addition than that with high proportion of MSS.The contents of Cd and Zn even exceeded the standard of soil quality while added with 50%-75% MSS in soil.Therefore,soil water-holding capacity and fertility in rocky desertification region could be improved with suitable dosage of MSS amendment,and low rate application(20%-35%)would take advantage of such effect.