地膜降解物对土壤微生物群落结构和多样性的影响

目的]研究降解地膜残余组分对土壤微生物群落结构和多样性的影响,为环境友好型地膜研发过程中选择对土壤环境有最小负效应的聚乙烯分子量和降解模式提供理论参考。方法]以L9(34)设计试验,采用PCR-DGGE检测技术分析混入地膜粉末的土壤在3a后的土壤微生物群落结构。结果]土壤自身性质是影响土壤微生物群落结构和多样性变化的主要因素。就聚乙烯因素而言,Mn=2 000(数均分子量,下同)和线性低密度聚乙烯(LLDPE)在以大残留量处理的土壤中的微生物群落结构较之对照处理有明显变化;混入小分子量聚乙烯、大分子量大残留量聚乙烯的土壤中微生物群落多样性丰富。不同处理的土壤微生物复杂系数分别增加了18.7%和2.6%。结论]不同处理间土壤微生物群落结构和多样性有明显差异,且各处理组土壤微生物的数量与相应对照组相比,多表现出增加的趋势。

Effects of Membrane Degradation Production on Community Structure and Diversity of Soil Microorganisms

Objective] The effects of membrane degradation residuals on community structure and diversity of soil microorganisms were investigated. These results were expected to provide theoretical references for polyethylene film engineering selection with respect to its molecular weight and degradation model. The selection is inferred that an environmental-friendly kind of polyethylene have the minimum negative effects on soil environment. Methods] Orthogonal experiment L₉(3⁴) and the PCR-DGGE measurement were adopted to analyze the community structure of microorganisms in soil treatments which were mixed with plastic powder in three years. Results] The results showed that soil properties were the main factors which influence the variations of community structure and diversity of soil microorganisms. The polyethylene with number-averaged molecular weight of 2 000 and linear low density polyethylene(LLDPE) in the soil which treated with large membrane degradation residuals has a more obvious influence on the community structure of microorganisms than the influences that other matched group been observed. The community diversity of microorganisms in the soils which were mixed with low molecular weight polyethylene and large molecular weight polyethylene with large membrane degradation residuals became more abundant. The complexity coefficients of soil microorganisms in different test treatment increased with 18.7% and 2.6%, respectively. Conclusion] Differences of community structure and diversity of soil microorganisms among the treatment were visible, and the number of soil microbial in all treatments showed an increasing trend when compared with the number of the corresponding control group.