黄河源高寒草甸退化秃斑地土壤基本特征及其风蚀规律

Soil Basic Characteristics and Wind Erosion in Degraded Barren Patches of Alpine Meadow in the Source of Yellow River

[目的]阐明高寒草甸不同类型退化秃斑地的土壤基本特征及其风蚀规律,揭示土壤物理力学特性与土壤风蚀之间的交互影响作用,进而为黄河源区生态植被的修复和保护提供理论依据。[方法]以黄河源7种草甸退化秃斑地及高原鼢鼠鼠丘为研究对象,结合野外调查和原位试验,对不同秃斑地土壤物理力学特征、土壤风蚀规律的差异性及土壤风蚀量与可蚀性因子间的关联度和相关性等进行了分析和讨论。[结果](1)不同退化秃斑地土壤基本物理力学特性指标差异较显著,7种秃斑地的平均土壤含水率、密度、紧实度和黏聚力分别是高原鼢鼠鼠丘的1.3倍、2.6倍、14.2倍和5.0倍,秃斑地中风毛菊的恢复生长对土壤的保水固土能力最强,香薷草和臭蒿相对较弱。(2)风蚀60 min后高原鼢鼠鼠丘土壤的总流失量是退化秃斑地的1.3~4.4倍;风蚀量的增加幅度随风蚀时间呈先增后减的趋势,风蚀作用的前5~10 min是土壤风蚀的敏感期;不同退化秃斑地土壤风蚀量与植被恢复类型有关,且与土壤物理力学指标值之间呈反比例关系。(3)退化秃斑地土壤风蚀量与植被覆盖度、土壤含水率和土壤紧实度之间均呈线性负相关关系,与土壤黏聚力间呈指数函数负相关关系;土壤风蚀量与覆盖度、含水率、紧实度和黏聚力间存在极显著负相关,与土壤密度和土壤平均粒径分别存在显著负相关和显著正相关。[结论]不同类型的退化秃斑地均可通过提升土壤基本物理力学特性,从而对土壤风蚀产生抑制效应,其中风毛菊抑制效果最佳、香薷草和臭蒿相对较弱。

[Objective]The aims of this study are to clarify the basic characteristics of soil and the pattern of wind erosion in different types of degraded bare patches in alpine meadow,reveal the interaction between soil physical and mechanical properties with soil wind erosion,then provide a theoretical basis for the restoration and protection of ecological vegetation in the source region of the Yellow River.[Methods]Based on the field investigation and in-situ test,the physical and mechanical characteristics of soil,the difference of soil wind erosion pattern and correlation between soil wind erosion and erodibility factors were analyzed and discussed in seven kinds of meadow degraded barren land and plateau zokor mound in the Yellow River source.[Results](1)There were significant differences in the basic physical and mechanical properties of soils in different degraded bald land.The average soil moisture content,density,compactness and cohesion of seven bald land were 1.3 times,2.6 times,14.2 times and 5.0 times of plateau zokor hill,respectively.The restoration and growth of Saussurea eopygmaea in bald land had the strongest ability to retain water and soil,while Elsholtzia densa and Artemisia hedinii were relatively weak.(2)After 60 min of wind erosion,the total soil loss of plateau zokor mound was 1.3~4.4 times that of degraded barren land;the increment of wind erosion amount increased first and then decreased with the wind erosion time.The first 5~10 min of wind erosion was the sensitive period of soil wind erosion.Soil wind erosion in different degraded bald spots was related to vegetation restoration types,and was inversely proportional to soil physical and mechanical index values.(3)There was a linear negative correlation between soil wind erosion and vegetation coverage,soil moisture content and soil compaction,and an exponential negative correlation between soil wind erosion and soil cohesion.Soil wind erosion was significantly negatively correlated with soil cover,moisture content,compactness and cohesion,and significantly negatively correlated with soil density and soil average particle size,respectively.[Conclusion]Different types of degraded bare lands have an inhibitory effect on soil wind erosion by improving the basic physical and mechanical properties of soil.Among them,the inhibition effect of Saussurea eopygmaea is the best,and the inhibition effect of Elsholtzia densa and Artemisia hedinii are relatively weak.