以探讨荒漠草原表层土壤粒径分布分形、不同粒径有机碳含量、碳库管理指数特征及其关系为目的,通过野外调查选取宁夏回族自治区盐池县花马池镇荒漠草原柠条锦鸡儿(Caragana korshinskii)、黑沙蒿(Artemisia ordosica)、短花针茅(Stipa breviflora)、蒙古冰草(Agropyron mongolicum)4种典型植被作为研究对象,采集典型植被冠下和丛间2种生境下表层(0-5 cm)土壤,分析不同植被表层土壤不同粒径有机碳含量、土壤碳库动态变化特征及其相关性。结果表明:(1)4种典型植被土壤粒径呈"单峰"型分布趋势,土壤颗粒主要集中分布于2~250 μm粒径,分形维数(D)为2.56~2.63,100~500 μm颗粒含量是植被间差异显著的主要原因。(2)4种典型植被冠下有机碳含量大于丛间有机碳含量,>250 μm粗砂粒组分有机碳含量最高,不同粒径组分有机碳含量在灌丛和草本植被间差异显著(p<0.05)。(3)4种典型植被土壤TOC、AOC含量均表现为冠下大于丛间,TOC在不同群落间差异显著,灌木群落冠下碳库活度(A)和碳库管理指数(CPMI)相对大于丛间,各指标在不同群落间因生境不同差异较大,表明不同典型植被在碳库循环机制中扮演不同角色,不同程度增强土壤碳汇功能。(4)土壤粒径分形与碳库稳定性关系复杂,2~50 μm细粉粒是土壤有机碳无机胶体,其含量增多明显提高土壤颗粒与有机碳形成有机-无机胶结体的机会,对维持土壤结构和有机碳库稳定性具有重要意义。研究结果表明适宜的植被恢复措施对维持荒漠草原土壤颗粒及土壤有机碳库稳定性具有一定的参考价值。
To explore the fractal distribution of surface soil particle size, organic carbon content of different particle size and the characteristics of carbon management index as well as their relationship in the desert steppe, 4 kinds of typical communities in Huamachi Town, Yanchi County, Ningxia Hui Autonomous Region, including Caragana korshinskii, Artemisia ordosica, Stipa breviflora and Agropyron mongolicum, were selected as the research objects. Using surface soil (0-5 cm) under typical vegetation canopy and intercropping habitats, the dynamic changes and their correlations of organic carbon content of different particle size and soil carbon pool in different vegetation surface soils were analyzed. The results showed that:(1) The distribution of soil particle size of the four kinds of typical communities showed a "single peak" shape, soil particle concentrated in the range of 2~250 μm, the fractal dimension D in the range of 2.56 to 2.63, the content of particle within 100~500 μm was the main reason for significant differences between vegetation types. (2) The organic carbon content under the canopy of four typical vegetation types was greater than that of intercropping habitats, the organic carbon content of thick sand >250 μm was the highest, the organic carbon content of different particle size components varied significantly between the shrub and herbage vegetation (p<0.05). (3) The soil TOC and AOC contents of the four typical vegetation types were all higher under canopy than those of intercropping habitats. TOC varied significantly among different communities. The carbon pool activity (A) and carbon pool management index (CPMI) under the canopy of shrub communities were relatively higher than those of intercropping habitats. Various indicators varied greatly among different communities due to different habitats, indicating that different typical vegetations played different roles in the carbon pool cycling mechanism, and enhanced soil carbon sink function with different degrees. (4) The relationship between soil particle size fractal and carbon pool stability was complex. Fine silt with 2~50 μm was an inorganic colloid of soil organic carbon. The increasing of its content significantly increased the opportunity for soil particles and organic carbon to form organic-inorganic cement, which was of great significance for maintaining soil structure and the stability of organic carbon pool. The research results indicated that appropriate vegetation restoration measures had certain reference value for maintaining the stability of soil particles and soil organic carbon pools in desert grassland.
张义凡, 陈林, 张蚌蚌, 李学斌.荒漠草原表层土壤有机碳粒径组分及碳库管理指数特征[J].水土保持学报,2023,37(5):283~290复制