论文部分内容阅读
以贵州西南部典型石漠化治理示范区的灌丛、水田、旱地、退耕3年草丛和退耕15年草丛为研究对象,分析了不同层次(0~10、10~20和20~30 cm)土壤有机碳含量及其矿化速率,探讨了喀斯特山区土地利用对土壤有机碳周转速率的影响。结果表明:5种土地利用类型土壤有机碳平均含量分别为30.37、31.24、21.86、17.49和22.50 g·kg-1,灌丛和水田的土壤有机碳含量均显著高于旱地、退耕3年草丛和退耕15年草丛(P<0.05);土壤有机碳的矿化规律表现为培养前期矿化速度快,培养中后期逐渐变缓。不同土地利用类型土壤有机碳的矿化速度存在差异,退耕3年草丛和退耕15年草丛的矿化速度较快,旱地的矿化速度快于水田;0~10和10~20 cm土层,灌丛土壤有机碳半衰期最长,分别为722和639d,水田土壤有机碳含量及半衰期在各层次均高于旱地及其退耕草地,表明水田可以作为喀斯特山区长期固碳的优势土地利用类型。总之,土地利用,特别是退耕,是影响喀斯特地区土壤有机碳周转速率的重要因素。
Taking shrubs, paddy fields, dry land, three years of returning farmland and 15 years of returning farmland to grassland in the typical rocky desertification control demonstration area in southwestern Guizhou as the research object, the effects of different levels (0 ~ 10, 10 ~ 20 and 20 ~ 30 cm) Soil organic carbon content and mineralization rate, and discussed the impact of land use on soil organic carbon turnover rate in karst mountain area. The results showed that the average contents of soil organic carbon in the five land use types were 30.37, 31.24, 21.86, 17.49 and 22.50 g · kg-1, respectively. The soil organic carbon contents in shrub and paddy fields were significantly higher than those in dry land, After 15 years of grassland reforestation (P <0.05), mineralization of soil organic carbon was characterized by rapid mineralization in the early stage of culture and gradual slowing down in the middle and late stages of cultivation. The mineralization rates of soil organic carbon varied with different land use types. The three years of grassland conversion and 15 years of grassland conversion showed faster rates of mineralization, and the rates of mineralization in dry land were faster than those in paddy fields. In 0-10 and 10-20 cm soil layers, The half-life of organic carbon in shrub soil was the longest, which was 722 and 639 d, respectively. The contents of organic carbon and half-life of paddy soil were higher than those in dry land and grassland at all levels, indicating that paddy field could be the dominant land use type for long-term carbon sequestration in karst mountains. In short, land use, especially returning farmland, is an important factor affecting the rate of soil organic carbon turnover in the karst area.