蚯蚓对废纸屑再利用及养分贫瘠土壤综合质量的影响

Impacts of earthworms on the reutilization of office wastepaper and the comprehensive quality of nutrient-poor soil

办公废纸屑作为常见有机废弃物,由于体积小且转化为再生纸成本高,因而再利用很难。但其含有大量有机碳(特别是纤维素)可能有助于退化土壤修复。蚯蚓对土壤有机质分解和其他土壤功能有重要影响,办公废纸屑和蚯蚓共同作用如何影响养分贫瘠土壤质量至今未知。研究以赤子爱胜蚓为接种蚯蚓,将办公废纸屑添加到养分贫瘠土壤中,分别设置纯土壤培养为对照组(S)、单独添加废纸屑(SP)、单独接种赤子爱胜蚓(SE)和添加废纸屑并接种赤子爱胜蚓的处理(SPE),比较培养90 d后各处理理化指标(pH、有机碳、全氮、全磷、全钾、碱解氮、速效磷、速效钾、交换性阳离子钾、钠、钙、镁等)、微生物磷脂脂肪酸(PLFAs)总含量和微生物结构的差异,在此基础上综合评价土壤质量,阐明废纸屑和赤子爱胜蚓在养分贫瘠土壤改良修复中的作用。结果显示:SPE处理较SP处理显著提高废纸屑的分解率89.48%。与对照相比,SP处理能够显著提高土壤pH值2.94个单位,SPE处理能够使其维持在中性水平;前者显著提高土壤有机碳(SOC)125.76%,交换性钠钙镁(Na_(Ex)、Ca_(Ex)、Mg_(Ex))154.00%、65.28%、55.25%,后者则明显增加SOC含量522.88%,全氮(TN)1365.29%,全磷(TP)36.26%,速效钾(AK)42.84%,交换性钾(K_(Ex))、Na_(Ex)、Ca_(Ex)、Mg_(Ex) 42.69%、160.35%、386.00%、110.36%。与对照S相比,SP和SPE处理均能显著提高真菌、放线菌、革兰氏阳性菌、革兰氏阴性菌、一般细菌和总PLFAs含量以及真菌/细菌,显著降低了革兰氏阳性菌/革兰氏阴性菌(P<0.05)。主成分分析中S、SP、SPE处理土壤综合质量差异显著(P<0.05),不同处理的质量指数呈现废纸屑+蚯蚓处理>废纸屑处理>对照,且土壤质量与微生物结构及生物量的关系更为密切。综上所述,在养分贫瘠土壤中赤子爱胜蚓堆肥废纸屑可以通过调节微生物群落结构,改变土壤pH和养分含量来提高土壤综合质量。这为废纸屑的资源化利用和养分贫瘠土壤的改良修复提供科学参考。

Office wastepaper,as a common organic waste,is not easy to reuse because of their small size and high costs of converting into recycled paper.A large amount of organic carbon(especially cellulose)in wastepaper may improve the remediation of degraded soil.Earthworm plays an important role on organic matter decomposition and other soil functions.Effects of office wastepaper and earthworms on the comprehensive quality of nutrient⁃poor soil are still largely unknown.In this study,Eisenia fetida were inoculated into the nutrient⁃poor soil along with office wastepaper in the laboratory for 90 days.Four treatments were conducted as follows:soil(S),soil+wastepaper(SP),soil+E.fetida(SE),and soil+wastepaper+earthworms(SPE).Soil pH,soil organic carbon(SOC),total nitrogen(TN),total phosphorus(TP),total potassium(TK),available nitrogen(AN),available phosphorus(AP)and available potassium(AK),cation exchange capacity(Na_(Ex),K_(Ex),Ca_(Ex),Mg_(Ex)),phosphdipid fatty acid(PLFAs)were determined in different treatments.Effects of wastepaper and E.fetida on the comprehensive quality of nutrient⁃poor soil were evaluated.Results were shown as follows:89.48%increase of wastepaper decomposition were found in the SPE than SP treatment.Significant increases of soil pH value were observed in SP(8.37)than that of S treatment(P<0.05).Soil pH value was at a neutral level in SPE.Compared with control(S),the SOC,Na_(Ex),Ca_(Ex) and Mg_(Ex) of SP treatment increased by 125.76%,154.00%,65.28%,and 55.25%.SOC,TN,TP,AK,K_(Ex),Na_(Ex),Ca_(Ex),and Mg_(Ex) of SPE increased by 1365.29%,36.26%,42.84%,42.69%,160.35%,386.00%and 110.36%.The addition of office wastepaper significantly improved soil microbial PLFAs contents(P<0.05).PLFAs contents of fungi(F),actinomycetes(ACT),gram⁃positive bacteria(G^(+)),gram⁃negative bacteria(G^(-)),common bacteria(CB),and total PLFAs(T⁃P)contents of SP and SPE treatments significantly increased(P<0.05).Moreover,the value of fungi PLFAs/bacteria PLFAs(F/B)of SP and SPE treatment significantly increased while gram⁃positive PLFAs/gram⁃negative PLFAs(G^(+)/G^(-))remarkably reduced(P<0.05).Principal component analysis and general indicator quality showed that the addition of wastepaper and the inoculation of earthworm improved soil comprehensive quality significantly(P<0.05).The average soil quality index showed that SPE>SP>S and more close relationship were observed between soil quality and microbial PLFAs.In summary,effects of office wastepaper and earthworm could improve soil comprehensive quality by adjusting microbial community structure and biomass,and changing soil pH and nutrient content in the nutrient⁃poor soil.It provided a scientific base on the resource utilization of office wastepaper and the remediation of nutrient⁃poor soils.