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以位于重庆市北碚区的缙云山为研究对象,通过采集亚热带常绿阔叶林(以下简称林地)、撂荒地、果园、坡耕地0~60cm深度的土壤样品,测定其MBC(微生物生物量碳)、MBN(微生物生物量氮)、DOC(可溶性有机碳)、DON(可溶性有机氮)含量,探讨土地利用方式对土壤活性有机碳、氮组分的影响.结果表明,4种土地利用方式下土壤MBC、MBN、DOC、DON含量均随着土壤深度的增加而降低.在0~60 cm的土壤深度内,土地利用方式对土壤MBC、MBN和DON含量的影响并不明显;撂荒地DOC含量显著高于其它3种土地利用方式,说明坡耕地撂荒能显著提高土壤DOC含量.在0~60 cm土层,林地、撂荒地、果园、坡耕地间MBN、DOC、DON分配比例均无显著差异,但坡耕地MBC分配比例显著高于其它3种土地利用方式,表明坡耕地土壤有机碳具有较高的生物活性,这可能是由于坡耕地施加绿肥以及粪肥等有机肥所致.各土地利用方式下DOC/DON最高,MBC/MBN次之,SOC/TN最低,说明可溶性有机质的生物固化作用最强,而土壤总有机质的矿化作用最明显.4种土地利用方式下SOC/TN、MBC/MBN及DOC/DON均为坡耕地最低,且比值都低于20,表明坡耕地土壤有机质的矿化作用较强,容易造成土壤碳的损失.
Taking Jinyun Mountain located in Beibei District of Chongqing Municipality as the research object, MBC (Microbial Biomass Carbon) was measured by collecting soil samples with depth of 0 ~ 60cm in subtropical evergreen broad-leaved forest (hereinafter referred to as woodland), wasteland, orchard, , MBN (microbial biomass nitrogen), DOC (dissolved organic carbon) and DON (soluble organic nitrogen) in the soil, and the effects of different land use types on soil active organic carbon and nitrogen components were studied.The results showed that soil MBC, MBN, DOC and DON all decreased with the increase of soil depth.Under the depth of 0 ~ 60 cm, the effect of land use on soil MBC, MBN and DON contents was insignificant; Higher than the other three kinds of land use patterns, indicating that abandoned farmland on sloping land can significantly improve the DOC content of soil.While in 0-60 cm soil layer, MBN, DOC and DON distribution ratio of forestland, fallow land, orchard, However, the distribution ratio of MBC on sloping farmland was significantly higher than that of the other three land use types, indicating that the soil organic carbon in sloping farmland had high biological activity, which may be due to the application of green manure and manure on sloping farmland. DOC / DON was the highest, MBC / MBN was the second, and SOC / TN was the lowest, indicating that the strongest biosolubilization of soluble organic matter and the most obvious mineralization of soil total organic matter were observed. / MBN and DOC / DON were the lowest on sloping farmland, and the ratios were below 20, indicating that the mineralization of soil organic matter on sloping farmland was strong and could easily lead to the loss of soil carbon.