不同植被类型对毛乌素沙地土壤有机碳的影响

摘要

通过对比分析毛乌素沙地9种主要植被类型样地中的土壤有机碳含量和密度及其在土壤剖面上的分布差异,研究了不同植被类型对毛乌素沙地土壤有机碳的影响.结果表明,0～80 cm深度的土壤有机碳密度与平均土壤有机碳含量的大小关系均为:马蔺群落＞芨芨草群落＞旱柳群落＞固定沙地油蒿群落＞沙柳群落＞半固定沙地 油蒿群落＞农田＞中间锦鸡儿群落＞流动沙地.随着土层加深,固定沙地油蒿群落、中间锦鸡儿群落、旱柳群落、芨芨草群落、马蔺群落和农田的有机碳含量均显著增加,而半固定沙地油蒿群落、流动沙地、沙柳群落的土壤有机碳含量随土层加深逐渐减少.各植被类型土壤有机碳密度在土壤剖面上的垂直分布格局和有机碳含量相似,但二者变化幅度不同.在流动沙地上进行植被建设有助于土壤固碳,且油蒿群落和沙柳群落的固碳效果较好.应尽量减少和避免强烈的人为干扰,以防止浅层土壤碳发生变化,维持土壤碳库稳定.%Through comparing the concentration and inventory of soil organic carbon (SOC) and its distribution in soil profiles under nine different vegetation types in the Mu Us desert,the effect of different vegetation types on SOC were studied.The order of the concentration and inventory of SOC in the 0 - 80 cm soil layer were: I-ris lactea var.chinensis community>Achnatherum splendens community> Salix matsudana community>Artemisia ordosica community on fixed sandy land> Salix psammophila community>Artemisia ordosica community on semifixed sandy land>farmland> Caragana intermedia community > shifting sandy land.With an increase of soil depth,the SOC concentration showed a significant accumulation in the A.ordosica community (fixed sandy land),C.intermedia community,S.matsudana community,A.splendens community,I.lactea var.chinensis community and farmland,but was gradually reduced in the A.ordosica community (semifixed sandy land),shifting sandy land and S.psammophila community.The distributions in soil profiles of SOC inventory and SOC concentration under each vegetation type were similar but differed in amplitude of variation.Vegetation construction on shifting sand would contribute to soil carbon sequestration and the A.ordosica and S.psammophila communities had better effects.Strong human disturbance should be reduced or avoided to prevent the change of carbon in shallow soil layers and to keep the stability of the soil carbon pool.