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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