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    辽东山区冰缘地貌大孔隙结构特征及其对团聚体稳定性和土壤可蚀性的影响

    Characteristics of the macropore structure of ice-marginal landforms in the Liaodong Mountain Area of northeastern China and its influence on soil aggregate stability and soil erodibility

    • 摘要:
        目的  为明确辽东山区冰缘地貌土壤大孔隙结构特征及其与团聚体稳定性和可蚀性之间的响应关系,探究林地大孔隙分布规律及土壤稳定性和土壤抗侵蚀能力。
        方法  选择辽东老秃顶子保护区的典型落叶阔叶林、暗针叶林、针阔混交林林地下的土壤为研究对象,结合土柱水分穿透试验和Poiseulle方程计算大孔隙数量、半径等指标,通过湿筛法测定团聚体组成和土壤稳定性等指标。
        结果  (1)不同林地类型大孔隙分布特征差异明显,与针叶林相比,阔叶林和针阔混交林大孔隙半径范围大,数量多。且针阔混交林土壤孔隙结构随土壤深度变化稳定;(2)林地土壤可蚀性因子K值整体分布在0.016 ~ 0.043之间,阔叶林 < 针阔混交林 < 针叶林,随土壤深度的增加,K值逐渐增加,土壤抗侵蚀能力下降;(3)相关分析显示,0.3 ~ 1.9 mm径级范围内的大孔隙数量与团聚体水稳性极显著正相关(P < 0.01);(4)通径分析显示,0.3 ~ 1.9 mm(特别是0.7 ~ 1.1 mm)径级范围内的孔隙数量越多,土壤抗侵蚀能力越强;大孔隙径级 > 1.9 mm后,单位面积大孔隙数量越多,半径越大,土壤抗侵蚀能力越差。
        结论  土壤大孔隙分布特征与土壤稳定性和可蚀性关系密切,孔隙尺度上,0.3 ~ 1.9 mm径级范围内,大孔隙数量与土壤稳定性和抗蚀能力呈正相关;径级 > 1.9 mm后,单位面积大孔隙数量及半径的增加降低土壤结构的稳定性和抗侵蚀能力;针阔混交林土壤大孔隙结构稳定性更高,可为辽东地区冰缘地貌区林分管理和土壤抗侵蚀能力评价提供科学指导和理论依据。

       

      Abstract:
        Objective  This paper aims to clarify the characteristics of soil macropore structure and its response relationship with aggregate stability and erodibility in the ice-marginal landforms of Liaodong Mountain Area of northeastern China, and to investigate the distribution pattern of forestland macropores and soil stability and soil erosion resistance.
        Method  Soil under typical deciduous broadleaved forest, coniferous forest and mixed coniferous and broadleaved forest in Liaodong Laotudingzi Nature Reserve were selected for the study. Combined with the soil column water penetration experiment and Poiseulle equation, indicators such as the number and radius of macropores were calculated, and indicators such as aggregate structure and soil stability were measured by wet sieve method.
        Result  (1) The distribution characteristics of macropores varied significantly among different forest types. Compared with coniferous forests, broadleaved forests and mixed coniferous and broadleaved forests had a larger radius range and a larger number of macropores. And the soil macropore structure of mixed coniferous and broadleaved forests varied stably with soil depth. (2) The overall distribution of soil erodibility factor K value in forest land ranged from 0.016 to 0.043, where broadleaved forest < mixed coniferous and broadleaved forest < coniferous forest, with the increase of soil depth, K value gradually increased and soil erosion resistance decreased. (3) Correlation analysis showed that the number of macropores in the diameter class range of 0.3 to 1.9 mm was highly significantly and positively correlated with the water stability of aggregates (P < 0.01). (4) Path analysis showed that the larger the number of macropores in the diameter class range of 0.3−1.9 mm (especially 0.7−1.1 mm) was, the stronger the soil erosion resistance was. When the size of macropores > 1.9 mm, the larger the number of macropores per unit area and the larger the radius were, the worse the soil erosion resistance was.
        Conclusion  Soil macropores are closely related to soil structural stability and erodibility. On the pore scale, the number of macropores is positively correlated with soil stability and erosion resistance in the diameter class range of 0.3−1.9 mm; after the diameter class > 1.9 mm, the increase in the number and radius of macropores per unit area reduces the stability of soil structure and erosion resistance; the macropore structure of soil in mixed coniferous and broadleaf forest is more stable, which can provide scientific guidance and theoretical basis for the management of forest stands and evaluation of soil erosion resistance in the ice-marginal terrain of Liaodong area of northeastern China.

       

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