岩溶山地不同土地利用方式土壤颗粒有机碳和矿物结合态有机碳的分布特征

Distribution Characteristics of Soil Particulate Organic Carbon and Mineral-associated Organic Carbon of Different Land Use in Karst Mountain

对重庆中梁山岩溶山地不同土地利用方式下0—40cm土壤颗粒有机碳和矿物结合态有机碳的含量和分布特征进行了研究。结果表明:不同土地利用方式土壤有机碳含量平均值表现为:林地>菜地>草地>橘园地>弃耕地。除橘园地外,其它各土地利用类型土壤细颗粒有机碳(FPOC)含量大于粗颗粒有机碳(CPOC)。不同利用方式土壤颗粒有机碳含量在剖面层次中表现不同。0—20cm表层土壤CPOC含量表现为:橘园地>草地>菜地>林地>弃耕地,差异较大。土壤FPOC含量表现为:林地>草地>菜地>橘园地>弃耕地;20—40cm土壤CPOC和FPOC最高值出现在菜地,最低值出现在弃耕地。不同土地利用方式土壤矿物结合态有机碳(MOC)含量和土壤有机碳含量分布特征一致。除橘园地外土壤各组分有机碳分配比例大致表现为:MOC/SOC>CPOC/SOC>FPOC/SOC。相关分析表明,不同土地利用方式土壤SOC和POC呈正相关,相关性不一致。林地和草地呈极显著相关(P<0.01),弃耕地呈显著相关(P<0.05),菜地和橘园地相关性不显著。表明人为干扰和耕作措施会影响POC对SOC的贡献。

The content and distribution characteristics of both soil particulate organic carbon（POC） and mineral-associated organic carbon（MOC） in the soil（0—40 cm） under different land use types were studied in Zhongliang knoll,Chongqing.The results revealed that：（1） the average content of the soil organic carbon（SOC） under different land use were woodlandvegetable landgrasslandgardenabandoned farmland;（2） the contents of soil fine particulate organic carbon（FPOC） were more than soil coarse particulate organic carbon（CPOC） in all land use except garden;（3） the contents of POC were different in the soil layer under different land use.Between 0—20 cm,the average contents of CPOC were gardengrasslandvegetablewoodlandabandoned farmland,and the contents were obviously different in each land with different use.The average contents of FPOC were woodlandgrasslandvegetable landgardenabandoned farmland.Between 20—40 cm,the highest content of CPOC and FPOC appeared in vegetable land,while the lowest occured in abandoned farmland,the distributions of the contends of MOC under different land use types were the same as SOC;（4） the component of soil organic carbon ratio was approximately expressed as： MOC/SOCCPOC/SOCFPOC/SOC except garden;（5） the correlation analysis shows that,under different land use types the SOC and POC were positively correlated,and correlation was not consistent,woodland and grassland correlated significantly（P0.01）,abandoned farmland correlated significantly（P0.05）,and vegetable and orchard land did not remarkably correlate.So,human interference and tillage would affect contribution POC′s in SOC pool.