凋落物化学组成对土壤微生物学性状及土壤酶活性的影响

通过模拟试验的方法研究了单一施加杉木(Cunn inghan ia lancceola ta(L am b)Hook.)叶凋落物,杉木(C.lancceola ta)和桤木(A lnus crem astogyne Burk ill)混合凋落物,杉木(C.lancceola ta)和枫香(L iqu id am ba f orm osana H ance)混合凋落物,杉木(C.lancceola ta)、桤木(A.crem astogyne)、枫香(L.f orm osana)混合凋落物对土壤化学性状和土壤微生物量碳、代谢熵(qCO2)、土壤酶活性的影响。研究结果表明,土壤微生物学性状比土壤化学性状对不同凋落物处理的效应反应更敏感;与单一杉木叶凋落物比较,混合凋落物处理的土壤微生物量碳明显增加,土壤脲酶、蔗糖酶、脱氢酶活性升高;土壤代谢熵(qCO2)和土壤多酚氧化酶活性有下降趋势;另外,研究结果也表明,不同树种的叶凋落物混合对土壤质量的影响存在差异,有桤木叶的混合凋落物对土壤质量的改善效果似乎更明显。

Effects of litter chemistry on soil biological property and enzymatic activity

Plant litter is the main source of organic matter in soils and its decomposition by microorganisms ensures the recycling of nutrients that can be recycle by plants.The chemical components of leaf litter can affect soil microbial activity.In this study,the effects of leaf litter qualities on soil chemical,microbial properties and soil enzymatic activities were investigated.We set up our experimental design based on using following litter combination such as: a) single leaf litter of Cunninghania lancceolata(Lamb) Hook(PS),b) mixture of leaf litter;50% C.lancceolata and 50% Alnus cremastogyne Burkill(SQ),c) mixture of leaf litter;50% C.lancceolata and 50% Liquidamba formosana Hance(SF),and d) mixture of leaf litter 33% each of C.lancceolata,A.cremastogyne and L.formosana(SQF). Results showed that leaf litter significantly influenced the level of soil microbial biomass carbon,metabolic quotient(qCO_2),and enzymatic activities in the soil while other soil parameters(total organic carbon(TOC),soil total N(TN),available P,NH~ _4-N and pH) did not showed the positive effect of leaf litter.Whereas,total P,total K,available K and(NO~-_3-N) were decreased in the order: SQ>SF>PS=SQF,SQF>SQ>SF>PS,SQ>PS>SF>SQF,SQF>SQ>SF>PS,respectively.Microbial biomass carbon(MBC) increased with decreasing C/N ratio of leaf litter.The C/N ratios of leaf litter in treatments(PS,SF,SQ,SQF) were 79.53,76.32,56.90,61.20,respectively.The values of qCO_2 decreased in such order: SQSF>SQF>SQ.Furthermore,the increase in C_(bio)/C_(org) indicated that the C compounds perhaps easily utilized by soil microorganisms and the turnover of soil organic matters showed faster in SQ than PS treatment.Soil urease,invertase and soil dehydrogenase activity were substantially lower in PS,while significantly higher in SQ treatment.However,soil polyphenol oxidase activity decreased in this order: PS>SF>SQ>SQF with significant differences between PS and SQF.Therefore changes in soil enzymatic activity further indicated that mixted leaf litter enhanced soil microbial activity,and improved soil biological fertility than from single Chinese fir leaf litter.