太岳山油松林土壤活性碳和微生物特性随外源有机物的变化规律

为探讨不同外源碳添加对森林土壤微生物—土壤酶—活性碳库系统的影响规律,在山西太岳山油松林展开了外源碳添加的野外控制试验.试验设计为5种处理,按照250 g·m-2的当量,分别向油松林表层土壤中添加了生物炭、玉米秸秆、辽东栎叶、油松叶和木屑等有机物,以未添加的样方作为对照.研究表明:外源碳的输入,显著提高了碳库各组分的含量和微生物呼吸值(P0.05).酶活性表现出明显差异,纤维素酶(BG、CBH)、几丁质酶(NAG)、氧化酶(PO、PER)活性分别在秸秆、木屑、油松处理下活性最高.代谢熵大小表现为:油松针叶辽东栎阔叶空白木屑生物炭秸秆;微生物熵变化趋势与代谢熵值变化趋势相反.碳库活度、微生物代谢特性和酶活性之间的相关性表现为:纤维素酶和代谢熵成负相关关系,与微生物熵则成正相关关系.氧化酶则与此相反.结合试验结果得出:秸秆和生物炭相较于其他三种处理,具备更强的固碳能力,同时秸秆显著地提高了森林土壤碳的周转速率.

Variations in labile soil carbon and microbial activity by organic matter input in Pinus forest in Taiyue mountain

To explore the feasibility of exogenous carbon on improving soil microbial organism, enzyme and labile soil carbon pool in forest, 5 types of carbon sources including biochar, corn stem, oak leaf, pinus leaf and sawdust were added at 250 g·m-2 in pinus forest in Shanxi, with no addition as control. The results indicated that all constituents of soil organic carbon and microbial respira-tion were greatly affected by organic matter additions ( P<0.05) . Corn stem, wood stem and pinus leaf significantly increased cellu-lose enzyme activities ( BG, CBH) , chitinase ( NAG) and oxidase ( PO, PER) . Level of soil microbial metabolic quotient ( qCO2 ) of various input declined sequentially in the following order of pinus leaf, oak leaf, the control, sawdust, biochar and corn stem, with microbial quotient ( Cbio/Corg ) being in the opposite sequence. Cellulose level was negatively correlated with qCO2 , but posi-tively correlated with Cbio/Corg . To summarize, corn stem and biochar demonstrated higher sequestration ability than 3 other materi-als. What′s more, straw improves the turnover rate of forest soil carbon significantly.