土壤粒径及有机碳特征对灌丛沙堆发育阶段的影响研究

Effect of Soil Particle Size and Organic Carbon Characteristics on the Development Stages of Caragana Korshinskii Shrub Nebkhas

为揭示风沙区柠条灌丛沙堆的发育规律,并为灌丛沙堆的发育阶段划分提供参考,对大、中、小三种柠条(Caragana korshinskii)灌丛沙堆顶部、中部和底部的土壤颗粒组成及分形维数、土壤有机碳特征进行研究。结果表明:土壤有机碳含量随灌丛沙堆的增大而递减,与灌丛及其沙堆的外部形态特征呈显著性负相关;随灌丛沙堆的增大,细砂含量逐渐增加,粉粒的含量逐渐减少;土壤粒径分形维数随灌丛沙堆的增大而递减,其与土壤黏粒、粉粒呈显著性正相关,与细砂、极细砂的百分含量呈负相关;土壤有机碳含量与土壤粒径分形维数之间存在显著性正相关。灌丛沙堆具有明显的空间异质性,沙堆上的土壤有机碳含量与土壤的颗粒组成与沙堆大小具有一定的相关性,并可作为划分沙堆发育阶段的标准,但需要充分考虑风力、植物和沙源等因素的影响。

Shrub nebkhas in Aeolian landforms usually develops as result of the deposition of wind-driven sediments around desert shrubs in arid and semi-arid regions. This study analyzed the soil particle composition, soil organic carbon and fraetal dimension at top, middle and bottom of shrub nebkhas of Caragana korshinskii, in order to reveal the development law of sandy landforms of C. korshinskii neabkhas and provide a reference for the division of developmental stages of nebkhas. The results showed that the content of soil organic carbon decreased with the increase of nebkhas size and it had significantly negative correlations with the morphological characteristics of shrub. With the increasing of nebkhas size, fine sand content increased gradually while silt content decreased. The fractal dimension presented a positive correlation with clay and sih but negative correlations with fine sand and silt. There was significant positive correlation between soil organic carbon content and soil particle size and fraetal dimension. Nebkhas showed obvious spatial heterogeneity. There was some relationship between soil organic carbon content and soil particle composition of nebkhas. Besides, to some extent, soil organie carbon content and soil particle composition of nebkhas could be used as standard for dividing the stages of nebkhas development, while the effects of wind, plant and sand source should be considered fully.