【摘要】 利用氯仿熏蒸法测定陕北黄土丘陵区不同土地利用类型下土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)和微生物生物量磷(MBP),并用常规方法测定土壤有机碳(SOC)和容重(BD),计算土壤有机碳密度(SOCD).研究结果表明:各样地表层土壤MBC、MBN、MBP分别在84.14～512.78、4.29～41.83、3.40～12.39mg/kg之间,微生物商(MBC/SOC)在2.84%～7.83%之间;土壤呼吸量(SR)在55.43～140.37mL/kg之间;MBC与SOC和SR呈极显著正相关,说明MBC不仅是SOC变化的敏感指标,并可用于指示土壤微生物活性;农地转变为人工林地和草地后会明显提高土壤微生物生物量和有机碳密度,表层土壤增幅最明显.更多还原

【Abstract】 Soil microbial biomass C(MBC),microbial biomass N(MBN)and microbial biomass P(MBP)under different land-use types in the loessial hilly-gully region were measured by the fumigation-extraction method.Soil organic carbon and bulk density were measured by the traditional method and soil organic carbon density(SOCD)was calculated.Results indicate that microbial C ranges from 84.14 to 512.78 mg/kg,microbial N from 4.29 to 41.83 mg/kg and microbial P from 3.40 to 12.39 mg/kg.The MBC/SOC ranges from 2.84% to 7.83%.And the soil respiration(SR)ranges from 55.43 to 140.37 mL/kg.Soil microbial biomass are markedly correlated with soil organic carbon and SR,which indicate that MBC is not only the sensitive index of SOC but also indicating soil microbial activities.The conversion of cropland into planted forest land and grass land resulted in a remarkable increase in the amounts of microbial biomass and soil organic carbon density,especially in the topsoil.更多还原