滇中尖山河小流域不同土地利用类型土壤活性有机碳分布特征

土壤活性有机碳对土地利用方式最为敏感，定量分析不同土地利用方式对土壤活性有机碳分布特征的影响对流域的土壤碳循环研究具有重要意义。从滇中尖山河小流域坡耕地、荒草地、林地、园地4种不同土地利用类型角度，系统地分析了0—10，10—20，20—30 cm土层土壤有机碳（SOC）、微生物有机碳（MBC）、易氧化有机碳（EOC）及可溶性有机碳（DOC）的分布特征及其相关性。结果表明:不同土地利用类型下土壤SOC，MBC，EOC，DOC整体均表现为园地 > 林地 > 坡耕地 > 荒草地；4种土地利用类型MBC，EOC，DOC整体上随着土层深度的增加而逐渐降低，且主要分布在0—20 cm土层，在20—30 cm土层含量较低（低于30%）；4种土地利用类型下SOC和MBC，EOC，DOC呈极显著正相关关系，MBC，EOC，DOC两两之间也表现出极显著正相关。综上，退耕还林以及在荒草地种植人工林可作为提高土壤有机碳及活性有机碳含量的有效措施，并将在减少流域水土流失和面源污染、改善土壤质量、恢复土壤肥力等方面起到重要作用。

Distribution Characteristics of Soil Active Organic Carbon in Different Land Use Types in Jianshan River Watershed in Middle Yunnan Province

Soil activated organic carbon is the most sensitive to land use types. The effects of different land use types on the distribution characteristics of soil activated organic carbon were quantitatively analyzed, which had great importance for the study of soil carbon cycle in the watershed. The distribution characteristics of soil organic carbon (SOC), microbial biomass carbon (MBC), easily oxidized organic carbon (EOC) and dissolved organic carbon (DOC) in 0-10 cm, 10-20 cm and 20-30 cm soil layers in Jianshan River watershed in Yunnan Province were systematically analyzed from four different land use types (sloping farmland, wild grass land, forest land, garden land). The results showed that SOC, MBC, EOC and DOC under different land use types decreased in the order:garden land > forest land > sloping farmland > wild grass land; SOC, MBC, EOC and DOC in the 4 kinds of land use types decreased with the increase of soil depth, and mainly distributed in 0-20 cm soil layers, with a low content (less than 30%) in 20-30 cm soil layers. SOC had significant positive correlation with MBC, EOC and DOC, and there were very significant positive correlation between MBC, EOC and DOC. In conclusion, converting cropland to forestland and planting artificial forest in wild grassland can be an effective measure to increase the content of soil organic carbon and active organic carbon. Soil erosion and surface pollution can be reduced, and soil quality, soil fertility and carbon reserves will be improved with these measures.