峡谷型喀斯特不同生态系统土壤团聚体稳定性及有机碳特征  

Stability and organic carbon characteristics of soil aggregates under different ecosystems in karst canyon region

作　　者：谭秋锦[1,2] 宋同清[1,3] 彭晚霞[1,3] 曾馥平[1,3] 杜虎[1,3] 杨钙仁[1,2] 范夫静[1,4] 

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]广西大学林学院,南宁530004 [3]中国科学院环江喀斯特农业生态试验站,广西环江547100 [4]江西农业大学,南昌330045

出　　处：《应用生态学报》2014年第3期671-678,共8页Chinese Journal of Applied Ecology

基　　金：中国科学院战略性先导科技专项(XDA05070404,XDA05050205);中国科学院“西部行动”计划项目(KZCX2-XB3-10);国家科技支撑计划项目(2011BAC09B02);国家自然科学基金项目(31370623,31370485,U1033004,31100329);广西科技攻关项目(桂科攻1123001-9C);广西特聘专家项目资助

摘　　要：通过野外调查与室内分析相结合的方法，对峡谷型喀斯特水田（ST）、旱地（HD）、草地（CD）、灌丛（GC）、人工林（RGL）、次生林（CSL）6种生态系统的土壤团聚体及其有机碳的分布特点进行了研究．结果表明：干筛处理下（除HD外）均以〉8mm的土壤团聚体含量最高，总体上不同粒径土壤团聚体含量呈现随粒径减小先降低后增加再降低的趋势；湿筛处理下（除HD外）均以〉5mm的土壤团聚体含量最高，总体上不同粒径土壤团聚体含量随粒径减少而降低．干筛处理土壤团聚体的平均质量直径（MMD）为ST〉CD〉RGL〉CSL〉GC〉HD；几何平均直径（GMD）为ST〉CD〉RGL〉CSL〉HD〉GC；湿筛处理的MMD为RGL〉CSL〉GC〉CD〉ST〉HD，GMD为CSL〉RGL〉GC〉CD〉ST〉HD，用湿筛的MMD特别是GMD评价喀斯特石灰土土壤团聚体质量性状比干筛指标更准确．团聚体机械稳定性的分形维数D表现为CD〉HD〉ST〉RGL〉CSL〉GC，水稳定性表现为GC〉CSL〉RGL〉HD〉CD〉ST．土壤SOC含量越高，D、MMD和GMD值越大，土壤结构越合理．不同生态系统下各粒径团聚体SOC含量均以0．053～0．25mm粒径最高，部分〉5mm粒径含量最低，但以〉5mm团聚体对土壤SOC的贡献率最高，且贡献率随着粒径的减小逐渐降低．Soil aggregates and their organic carbon distributions were studied under six ecosystems, i. e. , farmland （short for ST） , dry land （HD）, grassland （CD） , shrubbery （GC）, plantation （RGL） and secondary forest （ CSL）, in a karst canyon region of China by a combination of field in- vestigation and laboratory analysis. The result showed that, soil aggregates were dominated by parti- cles with sizes〉8 mm in the ecosystems except HD under dry sieving, and basically presented a trend of decreasing firstly, then increasing and finally decreasing along with particle sizes decrea- sing; while soil aggregates were dominated by particles with sizes 〉5 mm in the ecosystems except HD under wet sieving and decreased with decreasing of particle sizes. The mean mass diameter （MMD） was in the order of ST〉CD〉RGL〉CSL〉GC〉HD and the geometric mean diameter （GMD） was ST〉CD〉RGL〉CSL〉HD〉GC by dry sieving, and MMD was RGL〉CSL〉GC〉CD〉ST〉HD and GMD was CSL〉RGL〉GC〉CD〉ST〉HD by wet sieving. Therefore, MMD and especially GMD of wet sieving were more accurate than that of dry sieving to evaluate soil aggregates quality in the karst cannon region. The fractal dimension （D） of mechanical stability in soil aggregates followed the order of CD〉HD〉ST〉RGL〉CSL〉GC and the water stability was in the order of GC〉CSL〉RGL〉HD〉 CD〉ST. The higher the SOC content was, the larger values of D, MMD, GMD became, and the more sense the soil structure made. Soil organic carbon content was highest in the aggregate parti- cles with sizes ranging from 0.25 to 0. 053 mm, and the content in some particles with sizes 〉5 mm was lowest. However, the contribution rate of particles with sizes 〉5 mm was largest to soil organic carbon, which gradually decreased with the decrease of particle size.

关 键 词：土壤团聚体 稳定性 土壤有机碳 生态系统 峡谷型喀斯特 

分 类 号：S152.4[农业科学—土壤学]