不同林龄人工橘林土壤微生物区系的研究

目的]了解三峡库区宜昌市郊区不同种植年限的人工橘林土壤微生物区系的变化。方法]以种植年限不同的3个橘林土壤为研究对象,采用常规方法测定土壤pH、土壤微生物生物量碳、微生物生物量、氮和土壤主要养分含量,采用平板稀释法测定土壤三大类微生物区系的数量。结果]随着种植年限的增加,不同林龄人工橘林的土壤酸化程度加剧,土壤有机质和全氮含量先增加后降低。土壤微生物总数量呈下降趋势,其中细菌数量显著降低,放线菌数量变化不大,而真菌数量显著增加,土壤中细菌和真菌的比值(B/F)呈现降低趋势。土壤微生物生物量碳在小范围内波动,而土壤微生物生物量氮显著降低。结论]随着种植年限的增加,土壤pH降低,影响土壤微生物区系、土壤微生物生物量碳、微生物生物量氮和土壤主要养分的变化,进而影响土壤功能的正常发挥。

Study on Soil Microflora in Different-aged Orange Plantations

Objective] The research aimed to study the dynamic of soil microflora from different-aged orange plantations in Three Gorges Reservoir areas of Yichang.Method] The soil samples were collected from three different-aged orange plantations,and conventional methods were used to determine soil pH,soil biomass carbon and nitrogen as well as soil primary nutrient content.The quantity of three soil microfloras were analyzed using the method of plate dilution.Result] With the increasing of planting years,soil pH decreased,soil organic content and total nitrogen content first increased and then decreased,and the total microbial numbers decreased.Concentration of bacteria significantly reduced which were contrary for fungi.Little changes happened in concentration of actinomycetes.And the ratio of bacteria and fungi in soil(B/F) decreased.There was little change in soil microbial biomass carbon while significant reduction in soil microbial biomass nitrogen.Conclusion] With the increasing of planting years,soil pH decreased,and the dynamic of soil microflora,soil microbial biomass carbon and nitrogen,the soil primary nutrient were affected,which further affected normal functions of soil.