岩溶洼地土壤微生物指标对不同土地利用方式的响应

Responses of Soil Microbial Characters to Farm Land-use Types in Peak-Cluster Depression of Karst Region

为探索岩溶洼地典型农业土地利用方式对土壤微生物性质的影响,对比分析研究四种不同农业土地利用方式下表层土壤微生物量碳、微生物量氮、微生物量碳氮比、土壤基础呼吸、代谢熵、微生物熵等土壤微生物指标。结果显示,不同利用方式下土壤微生物指标差异显著(P<0.05),土壤微生物量碳和微生物量氮变化趋势一致,且与其余四个土壤微生物指标与微生物碳(氮)变化趋势不同,结合土壤的物理化学性质分析发现,土壤微生物碳氮比、土壤微生物代谢熵和微生物熵比其它土壤微生物指标对土地利用方式的响应更加敏感,因此,利用土壤微生物代谢熵、微生物熵衡量土地利用方式对土壤肥力的影响比微生物量碳氮等土壤微生物指标更可靠。

To explore the influences of land-use type on soil microbial characters in a peak-cluster depression of Karst region, soil microbial biomass carbon （Cmic）, soil microbial biomass nitrogen （Nmic）, Cmic to Nmic ratio （Cmic/Nmic）, soil basic respiration （SR）, SR to Cmic ratio （qCO2） and Cmic to soil organic carbon （Corg） ratio （Cmic/Corg） were studied in four different land-use types. Results showed that there was significant difference among the same microbial character of different land-use types. The variation trends of Cmic/Nmic, SR, qCO2 and Cmic/Corg were different with the ones of Cmic and/or Nmic in four land-use types. Combining with soil physical and chemical characters, the qCO2 and Cmic/Corg had more susceptible to different land-use types than the other soil microbial characters. For this reason, it was more credible using Cmic/Nmic, qCO2 and （or） Cmie/Corg to measure fertility of soil than the other microbial characters.