不同相对分子质量PBS基共聚物的降解产物对土壤微生物的影响研究

Impact of different molecular weight of PBS-based copolymer degradation process on soil microorganism

以陕西花园土为供试土样,采用室内模拟实验,在土壤中加入一定量的聚丁二酸丁二醇酯(PBS),研究不同数均相对分子质量的PBS(Mn分别为3.46×103、8.13×103、1.60×104、3.50×104)对土壤呼吸强度,微生物(细菌(bacteria)、真菌(fungi)、放线菌(actinomycetes))数量的影响,以此来探讨PBS降解产物对土壤微生物生理特性的影响。研究结果表明:①相对分子质量为3.46×103和8.13×103的PBS在其质量分数较低时有利于土壤呼吸强度的增加,有利于细菌的生长,最大增长幅度达到40%,在其质量分数较高时有利于真菌生长,最大增长幅度达到500%。②相对分子质量为1.60×104和3.00×104的PBS随着PBS质量分数的升高,对土壤呼吸强度和微生物数量的促进作用相应增加,对土壤呼吸强度的提高幅度最大达11.6%,对真菌的提高幅度达178%。

To discuss the influence of PBS-based copolymers degradation product on physiological characteristics of soil microorganism （soil respiration and microorganisms amount）, the indoor stimulation experiment were carried out by adding a certain amount of PBS-based copolymers with different molecular weight （Mn=3.46 × 10^3, 8.13 × 10^3, 1.60 × 10^4 and 3.50 × 10^4） into garden soil of Shaanxi. The results show that, （1）soil respiration and bacteria amount were increased when molecular weights of PBS-based copolymers were 3.46 × 10^3 and 8.13 × 10^3 at lower concentration, respectively. The biggest increasing rate of bacteria amount was 40% compared with that of the control group. Higher concentrations of PBS-based copolymers were beneficial to the fungi amount growth. The biggest increasing rate was 500%. （2）Soil respiration and microorganism amount were increased when molecular weights of copolymers were 1.60 × 10^4 and 3.00 × 10^4, respectively. The stimulative effect was more significant with higher copolymer concentration. The biggest increasing rate of soil respiration was 11.6%, and the biggest increasing rate of fungi amount was 178%.