厌氧消化污泥对退化苗圃土壤的改良效果研究

Effects of Anaerobically Digested Sewage Sludge Addition on Improvement of a Degraded Nursery Garden Soil

摘要:

通过连续3年施用厌氧消化污泥(ADSS)的土柱试验，测定了土壤基本理化指标和微生物学指标，并分析了土壤中重金属积累特征，以全面评价厌氧消化污泥施用对合肥某退化苗圃土壤的改良效果.结果表明：施用厌氧消化污泥3年后，苗圃土壤质地和理化环境有明显改善，其中土壤中可溶性总盐含量（TDS）下降了67.6%，电导率（EC）降低了45.3%，对因多年种植苗木造成次生盐渍化的苗圃土壤具有较好的改良作用.施用厌氧消化污泥明显（概率P<0.05）增加了土壤中有机质和养分的供给，较无添加厌氧消化污泥相比，3年连续施用厌氧消化污泥后，土壤中有机质增加了77.9%；有效态氮和磷分别增加了110%和95.4%.同时，施用厌氧消化污泥对苗圃土壤微生物生物量和代谢活性也具有显著（P<0.05）的提升作用，其中微生物生物量碳（MBC）较无添加厌氧消化污泥增加了207%；尿酶和碱性磷酸酶活性分别增加了118%和102%.由此表明，施用厌氧消化污泥可以全面提升退化苗圃土壤质量.另外，通过对土壤中主要重金属含量分析表明，连续3年厌氧消化污泥施用后，苗圃土壤中重金属借有所增加，但其含量远低于土壤环境质量二级标准（GB 15618—1995），但是长期施用厌氧消化污泥后的土壤重金属累积特征和生态风险还有待进一步深入研究.

Abstract:

A soil column experiment was conducted to evaluate the effect of 3-year consecutive application of anaerobically digested sewage sludge (ADSS) on a degraded soil from a nursery garden in Hefei City, Anhui Province. Soil physiochemical and microbiological parameters were determined, and accumulation characteristics of heavy metals in the soil were also analyzed. The results showed that 3 years after the ADSS addition, soil texture and physicochemical environment were significantly (P<0.05) improved, and the soil total dissolved salt (TDS) content and electric conductivity (EC) were decreased by 67.6% and 45.3%, respectively, which indicates that the ADSS application showed a improved effects on the degraded soil with secondary salinization due to continuous nursery plantation for several years. The application of ADSS significantly (P<0.05) increased soil organic matter content and nutrients supply. After 3-year ADSS application, soil organic matter was increased by 77.9% and the available nitrogen and phosphorus were increased by 110% and 95.4%, respectively, as compared with the control (no ADSS addition). At the same time, the ADSS application also significantly (P<0.05) enhanced nursery soil microbial biomass and metabolic activities. As compared to the control, soil microbial biomass carbon (MBC) was increased by 207%, and soil urease and alkaline phosphatase activity were increased by 118% and 102%, respectively. The above results showed that the application of ADSS could improve the degraded nursery soil quality. In addition, the nursery soil with 3-year application of ADSS showed an increase in the contents of heavy metals, but the contents of the determined heavy metals were far lower than the secondary level of soil environmental quality standard of China (GB 15618—1995). However the effects of long-term application of ADSS on accumulation of heavy metals in the nursery soil and its ecological risk need further study.