土壤风蚀环境下盐结皮研究及展望

A Review: The Formation, Development and Prospect of Soil Salt Crust on the View of Soil Erosion

盐结皮由盐结晶体胶结土壤颗粒形成于土壤上层,其广泛分布于干旱和半干旱区.盐晶体胶结土壤颗粒形成大团聚体显著地提高土壤抗风蚀能力,减少疏松地表粉尘释放量.自然盐结皮形状多样,盐结皮经历成长期、成熟期和消亡期演变阶段,三个阶段可相互转化.盐种类影响盐结皮类型,NaCl常形成表面盐结皮;Na_2SO_4形成次表层盐结皮且存在盐胀,常形成块状脊裂地表;混合盐则可以减轻盐胀,形成表面和次表层混合结皮.表面盐结皮整体覆于土壤表面,其抗风蚀性能优于块状脊裂次表层盐结皮.盐晶形状和阻水性能对土壤风蚀也存在较大影响.盐结皮及其抗土壤风蚀研究取得了一定进展,但在抵抗风沙灾害方式及其形成机理、盐性特征方面仍需进一步开展研究.

Salt crust is formed by salt grain cementing soil particles on soil upper layer, widly distributed in arid and semi-arid areas. The formation of large soil aggregates by salt crystal cementing fine particles significantly discreases the soil erodibility and reduces the dust release on the loose surface. Various shapes of salt crust are in nature. They exprences three stages, growth, maturity and extinction, and the stage can be transformed each other. The types of salt crust are affected by salt. NaCl generally forms efflorescence on soil, while Na2SO4 often forms subflorescence in upper soil and has salt expansion, developing polygon ridged surface. The mixed salt can discrease salt expansion, forming a mixed crust including efflorescence and subflorescnce. The erodibility of polygon ridged subflorescence crusts is much bigger than the efflorescence over the soil wholely. The shapes of salt crystal and the resisitance of water transport from the soil bottom significantly influence soil wind erosion. Although the great progress had been made in the salt crust study on soil wind erosion, it is still worth further study.