腾格里沙漠南缘植被恢复过程中土壤理化性状的变化

Change of Soil Properties with the Restoration of Vegetation in the South Fringe of the Tengger Desert

土壤有机碳是土壤质量的关键指标,也是评估陆地生态系统碳库对大气CO2源、汇效应转变的基础。本文分析了腾格里沙漠南缘植被恢复过程中土壤物理性质、有机碳含量及其组分特征。结果表明:在围封后,土壤容重随着植被恢复年限的延长呈指数级减小,孔隙度、黏粒含量和田间持水量则表现出随年限延长而显著增大的趋势;土壤有机碳、微生物量碳、轻组有机碳和重组有机碳含量随着围封抚育年限的延长而显著增加,轻组有机碳占总有机碳的比例随植被恢复年限的延长而增大,而重组碳所占比例则随时间变化显著下降。土壤有机碳与容重呈显著负相关,而与其他参数呈显著正相关,说明其变化受多种因素影响,且对土壤物理性质的变化有重要意义。

Soil organic carbon （SOC） is a key index of soil quality, and it is the basis for the appraisal of role transition of the terrestrial carbon pool between atmospheric carbon dioxide source and sink. The dynamics of bulk density, porosity, silt content, water-holding capacity, soil organic carbon content, light fraction carbon （LF-C） content, heavy fraction carbon （HF-C） content as well as microbial biomass carbon （MBC） content with the restoration o5 vegetation were investigated, the results showed that： bulk density exponentially decreased with the time extended after being exclosed, while porosity, silt content and water-holding capacity increased with vegetation restoration. Content of SOC, MBC, LF-C, HF-C showed a significant increase with the prolongation of time. The proportion of LF-C increased while the proportion of HF-C deceased gradually after the exclosure. SOC was negatively correlated with bulk density, while positive corre-lations were found between SOC and other parameters, which suggest the dynamics of SOC is affected by multiple factors.