不同经营措施对毛竹林土壤理化性质、酶活性和有机碳矿化特征的影响

Effects of Management Measures on Soil Physicochemical Properties,Carbon Mineralization and Enzyme Activities in Phyllostachys edulis Plantations

毛竹林是我国特有的具有显著固碳潜力的森林类型。笔者以不同经营类型(无经营M_(0)、粗放经营M_(1)和集约经营M_(2))毛竹林和对照天然次生林(CK)土壤为研究对象,通过室内模拟培养试验,探讨各经营类型毛竹林土壤理化性质、酶活性及有机碳矿化特征的差异。结果表明:降低毛竹林的经营强度后,土壤养分元素含量得到增加。无经营和粗放经营显著增加了毛竹林土壤的总有机碳、全氮、全磷和可溶性氮的含量,提高了土壤含水率并降低了土壤容重。与对照相比,无经营和粗放经营毛竹林土壤的β-葡萄糖苷酶、多酚氧化酶和过氧化物酶在0~20 cm和20~40 cm土层中均显著提高,土壤酸性磷酸酶活性则显著降低。各土壤潜在矿化有机碳量介于154~844 mg·kg^(-1),占土壤有机碳总量的0.82%~2.44%。相比对照,无经营显著增加了0~20 cm和20~40 cm土层中有机碳的潜在活性碳库以及累积碳矿化量,粗放经营次之。集约经营导致土壤碳矿化率显著高于其它经营土壤。总的来说,随着经营强度的增加,林下土壤呈现出理化性质和酶活性逐渐降低,有机碳矿化率逐渐增加的变化规律。因此,减少人为干扰降低经营强度有利于增加毛竹林土壤肥力,促进有机碳的周转。

Moso bamboo(Phyllostachys edulis)plantation is a unique forest type in China with significant carbon sequestration potential.The soil physicochemical properties,carbon mineralization and enzyme activities in Moso bamboo plantations subjected to different management measures(undisturbed(M0),extensively managed(M1)and intensively managed(M2))were studied in comparison to those in a secondary broad-leaved evergreen forest(CK).The results showed that after reducing the human interference with bamboo forest,the soil nutrient contents increased.Compared with the control,the contents of soil total organic carbon(TOC),total nitrogen(TN),total phosphorus and soluble organic nitrogen as well as soil moisture content in the undisturbed and extensively managed bamboo plantations significantly increased,while the soil bulk density decreased.The soilβ-Glucosidase,polyphenol oxidase and peroxidase activities in the 0~20 cm and 20~40 cm layers in the undisturbed and extensively managed bamboo plantations increased notably,but the activity of acid phosphatase decreased.The content of potential mineralizable organic carbon in each treatment ranged from 154 to 844 mg·kg^(-1),accounting for 0.82%to 2.44%of TOC.Compared with the control,the undisturbed management significantly increased the potential active carbon pool and cumulative carbon mineralization in the 0~20 cm and 20~40 cm layers,followed by the extensive management.Intensive management resulted in significantly higher soil carbon mineralization ratio than those in other treatments.In general,with the increase of management intensity,the soil physicochemical properties and enzyme activities decreased gradually and the organic carbon mineralization ratio increased steadily.Therefore,reducing human disturbance is conducive to enhancing soil fertility and facilitating the turnover of organic carbon in Moso bamboo plantations.