土地利用方式对土壤有机质及其碳库管理指数的影响

采用野外调查和室内分析的方式对子午岭不同土地利用方式下,土壤有机质、3种活性有机质及其碳库管理指数(CMI)进行了研究,结果表明,土壤有机质、3种活性土壤有机质含量均随土层的加深逐渐降低,在土壤剖面基本表现为林地、撂荒未翻耕地>撂荒翻耕地>农用地.同一土层,3种土壤活性有机质含量及其有效率表现为低活性有机质>中活性有机质>高活性有机质.不同利用方式下,活性有机质有效率随有机质活性增强,呈现撂荒未翻耕地>林地>撂荒翻耕地>农用地的趋势.不同利用方式之间的CMI的差异随有机质活性的增强而增大,且影响深度也逐渐加深.在0~30cm土层内,林地3种活性有机质的CMI高于撂荒翻耕地和农用地;而在30cm之下土层,3种利用方式低活性有机质的CMI相差不大,但中活性有机质和高活性有机质的CMI表现为林地>撂荒翻耕地>农用地.3种活性土壤有机质与其他生物化学性质之间均表现为显著或极显著相关关系,表明活性有机质可以指示土地利用方式对土壤有机质和CMI的影响.

Effects of land-use type on soil organic matter and carbon management index in Ziwuling area

The soil organic matter, soil labile organic matter and soil carbon management index(CMI) at different land use conditions in Ziwuling area were studied. The objective was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by land use patterns. The contents of soil organic matter and three labile organic matter contents decreased with the increase of soil depth, and presented the order of forest land, unploughed abandon land > ploughed abandon land > farmland in soil profile. Within the same depth, three labile organic matter contents and their efficiency ratios followed the order of low labile organic matter > middle labile organic matter > high labile organic matter. With the increase of organic matter activity, the efficiency ratios of three labile organic matters presented the order of unploughed abandon land > forest land > ploughed abandon land > farmland trend in profile soil. In the 0~30cm soil depth, the CMIs of low labile organic matters were markedly higher in forestry land than that in ploughed abandon land and farmland, but showed little difference in soils below 30 cm. However, the CMIs of middle and high labile organic matters were always present the order of forest > ploughed abandon land > farmland in the whole soil profile. The statistical analysis showed that the three labile organic matters were related with major soil properties at significant or very significant level, indicating that labile organic matter could be used to reveal the influence of land use on soil organic matter and carbon management index in Ziwuling area.