施用不同污泥堆肥对土壤理化性质及微生物活性的影响

Effect of Different Sludge Composting on Soil Physical and Chemical Properties and Microbial Activity

使用污泥园林废弃物混合堆肥、污泥好氧堆肥和污泥热水解堆肥3种污泥产品进行林地施肥试验,连续5个月(6—10月)监测人工林地3种施肥处理方式和空白对照(CK)的土壤酶活性、养分、重金属3类指标随采样时间推移的变化。结果表明:经过5个月的采样监测发现,施用污泥可提高土壤酶活性,其中碱性磷酸酶、过氧化氢酶活性最大可分别提高39%、8%,随着采样时间的变化,这2种酶均出现先上升后下降的趋势;蔗糖酶、脱氢酶、脲酶活性随采样时间推移不断下降,但是经过施肥处理的土壤酶活性均高于对照。3种堆肥处理的土壤微生物氮均高于对照,最大可提高126%。污泥好氧堆肥、污泥热水解堆肥处理的土壤微生物碳高于对照,最大可提高118%,表明施用污泥堆肥可提高土壤微生物碳、氮。施用污泥堆肥明显提高土壤中氮(N)、钾(K)、总有机碳(TOC)。3种污泥产品施用量均为30 t·hm^(-2),且施用污泥堆肥后,土壤中8种重金属质量分数均未超过国家农用地污染标准,表明按现有污泥产品施用量,林地土壤不存在重金属污染风险。

Three kinds of sludge products,namely,mixed compost of sludge garden waste,aerobic compost of sludge and thermolysis compost of sludge,thermolysis compost of sludge,were used to carry out fertilization experiment in forest land.The changes of soil enzyme activity,nutrient and heavy metal in artificial forest land under three fertilization treatments and blank control(CK)with sampling time were monitored for five consecutive months(June to October).After five months of sampling monitoring,the application of sludge could improve the soil enzyme activities,in which alkaline phosphatase and catalase increased by 39% and 8% at most.With the change of sampling time,the two enzymes showed a trend of first rising and then declining;the activities of sucrase,dehydrogenase and urease decreased with the sampling time,but the soil enzyme activities after fertilization treatment decreased all of them were higher than the control.The contents of urease,dehydrogenase,catalase and sucrase in October were lower than those in June under different treatments(including the control),while the contents of sucrase,catalase,dehydrogenase and urease in three fertilization treatments were higher than those in the control,which indicated that fertilization could improve the activities of soil enzymes.The contents of soil microbial carbon(MBC)and microbial nitrogen(MBN)in October were higher than those in June,and the contents of soil microbial nitrogen in three composting treatments were higher than those in the control,with a maximum increase of 126%.The content of soil microbial carbon in the treatment was higher than that in the control,with the maximum increase of 118%,indicating that sludge compost could increase the content of soil microbial carbon and nitrogen.The contents of nitrogen(N),potassium(K)and organic matter(TOC)in soil were significantly increased by applying sludge compost.The application rates of three sludge products were all 30 t·hm^(-2),and after the application of sludge,the contents of eight heavy metals in the soil did not exceed the national agricultural land pollution standard,and the contents of eight heavy metals in the soil did not exceed the national agricultural land pollution standard,indicating that according to the application rates of existing sludge products,there was no risk of heavy metal pollution in forest soil.