土壤有机质垂直分布特征及其对短期植被更替的响应

Vertical distribution characteristics of soil organic matter and its response to short-term vegetation succession

采集我国北京和云南地区约10a植被更替的0~110cm典型土壤剖面样品,分析土壤中有机碳稳定碳同位素比值(δ^(13)C_(org))、有机碳含量、有机碳碳密度、土壤有机质O/C和土壤有机质C/N等指标的垂向分布特征,探究了不同深度土壤对植被更替的响应,以揭示土壤有机质的垂直分布特征和稳定性规律.研究结果表明:土壤中δ^(13)C_(org)在不同地区和深度之间存在差异,北京和云南的深层土壤剖面中的土壤δ^(13)C_(org)随深度的变化规律相反,植被更替影响不同深度土壤的δ^(13)C_(org)改变率,北京地区土壤剖面在发生植被更替后,随着土壤深度增加,δ^(13)C_(org)改变率逐渐减小;土壤中有机碳含量、有机碳碳密度、土壤有机质极性和土壤有机质C/N的垂直分布的特征及其对植被更替的响应存在明显差异;部分典型剖面表现出植被更替可增加深层有机碳含量和土壤有机质极性的特征.表明在我国不同纬度、不同覆盖植被、不同土壤理化性质影响下,土壤有机质特性呈现出与分布深度和短期植被更替密切相关的规律性,或可为揭示植被更替与碳循环间的动态变化模型提供重要依据.

Typical soil profile samples were collected from depths ranging from 0 to 110cm in Beijing and Yunnan,China,over a period of approximately ten years of vegetation succession.The vertical distribution characteristics of soil organic carbon stable carbon isotope ratios(δ^(13)C_(org)),total organic carbon,organic carbon density,O/C ratio,and C/N ratio in soil organic carbon were analyzed to investigate the response of soils at different depths to vegetation succession.The objective was to reveal the vertical distribution characteristics and stability patterns of soil organic matter.The study found that soilδ^(13)C_(org) varied significantly across different regions and depths.Notably,theδ^(13)C_(org) patterns in the deep soil profiles of Beijing and Yunnan were inversely related,with vegetation succession impacting theδ^(13)C_(org) change rate at various soil depths.In the Beijing area,theδ^(13)C_(org) change rate decreased with increasing soil depth following vegetation succession.Furthermore,the vertical distribution characteristics of total organic carbon,organic carbon density,soil organic matter polarity,and C/N ratio,as well as their responses to vegetation succession,differed markedly.Some typical profiles indicated that vegetation succession could enhance total organic carbon and soil organic matter polarity in deeper soil layers.The findings suggest that under the influence of varying latitudes,different vegetation covers,and distinct soil physical and chemical properties,the characteristics of soil organic matter are closely linked to distribution depth and short-term vegetation succession.These insights may provide a crucial basis for understanding the dynamic interactions between vegetation succession and the carbon cycle.