土地利用方式对土壤活性有机碳含量影响的初步研究

以我国川中丘陵区紫色土为背景,研究了5种不同土地利用方式对土壤活性有机碳(可溶性有机碳和微生物量碳)含量的影响,分析了可溶性有机碳(DOC)、微生物量碳(MBC)、总有机碳(TOC)的关系。结果表明,土地利用方式对土壤活性有机碳有显著影响。DOC含量呈现菜地>果园>水田>林地>旱地的趋势;MBC含量为水田>果园>菜地>林地>旱地。有机物质的输入量、种植制度和土壤管理措施是差异存在的重要原因。菜地、旱地、林地、果园和水田的DOC/TOC均值分别为0.58%、0.28%、0.19%、0.57%和0.28%,其相应的MBC/TOC均值分别为3.57%、3.09%、2.38%、2.67%和3.42%。经相关性分析,5种土地利用方式DOC、MBC含量与TOC之间的差异性达到了显著或极显著水平。

Effects of Land Use on the Contents of Soil Active Organic Carbon

The contents of soil active organic carbon(dissolved organic carbon,DOC;microbial biomass carbon,MBC) of different soil samples were investigated at five different land use sites in hilly area of purple soil,Sichuan Basin,and the relationships between DOC,MBC,TOC(total organic carbon) were analyzed.The results showed that the contents of DOC and MBC under fiver land used patterns were obviously different and DOC generally followed the series vegetable>orchard>paddy>forest>arable,the content of MBC was paddy>orchard>vegetable>forest>arable,the significant difference was derived from the distinctness of organic matter input,farming system and soil management types.DOC constituted 0.58%,0.28%,0.19%,0.57% and 0.28% of TOC under vegetable,arable,forest,orchard and paddy.MBC constituted 3.57%,3.09%,2.38%,2.67% and 3.42% of TOC under vegetable,arable,forest,orchard and paddy,respectively.Soil active organic carbon could be used as an index of soil fertility because of its close correlation with soil physiochemical properties.The contents of DOC and MBC have correlation to different degree with soil organic carbon at five different land use sites.