亚热带5个生态系统土壤微生物学性质比较

Comparsion of Soil Microbiology Characteristics in Five Subtropical Ecosystems

为了解亚热带生态系统土壤微生物学特性,对疏草荒地（Barren grassland）、纯杉木林（Cunninghamia lanceolata forest）、纯樟树林（Cinnamomum camphora forest）、杉木樟树混交林（Cunninghamia lanceolata-Cinnamomum camphora mixed forest）和自然恢复地（Nature recovery）等5种生态系统土壤微生物学性质进行了分析。结果表明,在0-20、20-40和40-60 cm土层,纯樟树林、杉木樟树混交林和自然恢复地的土壤微生物生物量碳氮磷和土壤基础呼吸显著高于疏草荒地和纯杉木林（P〈0.05）,而他们的代谢熵低于疏草荒地和纯杉木林（P〈0.05）;随着土层深度的增加,不同生态系统的土壤微生物生物量碳氮磷和土壤基础呼吸显著减小（P〈0.05）,代谢熵显著增大（P〈0.05）。土壤容重与土壤微生物生物量碳氮磷和土壤基础呼吸呈显著负相关（P〈0.05）,与代谢熵呈显著正相关（P〈0.05）;土壤微生物生物量碳氮磷和土壤基础呼吸均与土壤总孔隙度、土壤水稳性大团聚体、土壤有机碳、全氮、有效氮、有效磷呈极显著正相关（P〈0.01）,代谢熵与土壤总孔隙度、土壤水稳性大团聚体、土壤有机碳、全氮、有效氮和有效磷呈显著负相关（P〈0.05）。因此,自然恢复地、纯樟树林和杉木樟树混交林对土壤质量的改善有明显促进作用,而疏草荒地和纯杉木林对土壤改良效果不明显。

In order to understand the soil microbiology characters of subtropical ecosystem, the soil microbial physio-chemical properties were studied in five ecosystems, such as barren grassland（BG）, Cunninghamia lanceolata forest（CL）, Cinnamomum camphora forest（CC）, Cunninghamia lanceolata-Cinnamomum camphora mixed forest（CL-CC） and nature recovery（NR）. The results showed that soil microbial biomass carbon, nitrogen and phosphorus（SMBC, SMBN and SMBP） and soil basal respiration（SBR） in CC, CL-CC and NR were significantly higher than those in BG and CL（P〈0.05） at 0- 20, 20- 40 and 40- 60 cm soil layers, whereas metabolic quotient（qCO_2） in CC, CL-CC and NR was significantly lower than that in BG and CL（P〈0.05）. SMBC, SMBN, SMBP and SBR significantly decreased with increment of soil depth（P0.05）, while q CO2 significantly increased in all ecosystems（P〈0.05）. Soil bulk density（SBD） had significantly negative correlation with SMBC, SMBN, SMBP, and SBR（P〈0.05）, significantly positive correlation with q CO2（P〈0.05）. SMBC, SMBN, SMBP, SBR had significantly positive correlation with soil total porosity（STP）, soil water stable macro-aggregate（SWSM）, soil organic carbon（SOC）, total nitrogen（TN）, available nitrogen（AN）, and available phosphorus（AP）（P〈0.01）, and q CO2 had significant negative correlation with STP, SWSM, SOC, TN, AN, AP（P〈0.05）. Therefore, NR, CC and CL-CC could significantly improve soil quality, but BG and CL had not obvious amelioration to soil quality.