Improving soil hydraulic properties is one of important purposes of soil tillage. Recent studies on permanently charged soil have shown specific cation effect on soil water infiltration. In this study, specific cation effects on soil water infiltration and soil aggregate stability of both variably and permanently charged soils were comparatively examined. It was found that, specific cation effects on soil water infiltration and soil aggregate stability are quite different for permanently and variably charged soils. For the permanently charged soil, the sequence of specific cation effects on soil water infiltration was Li+ << K+ < Cs+, which was in accordance with the cation polarizability sequence of Li+ (0.029 Å3) << K+ (0.88 Å3) < Cs+ (2.56Å3); but for the variably charged soil, the sequence changed to Cs+ > Li+ > K+. Moreover, the sequence of cation concentration effect on permanently charged soil water infiltration rate (SWIR) was SWIR (0.0001 mol/L) < SWIR (0.001 mol/L) < SWIR (0.01 mol/L) < SWIR (0.1 mol/L) whereas that for the variably charged soil changed to SWIR (0.1 mol/L) < SWIR (0.0001 mol/L) ≈ SWIR (0.01 mol/L) < SWIR (0.001 mol/L). The differences of specific cation and cation concentration effects on soil water infiltration for the two soils came from those on soil aggregate stability. For permanently charged soils, soil electric field determined soil aggregate stability. However, for variably charged soils, besides soil electric field, osmotic pressure, positively charged colloids and surface reaction of metal cation may possibly play critical role in soil aggregate stability.

中文翻译：

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特定阳离子对土壤水分渗透和土壤团聚体稳定性的影响——可变和永久带电土壤的比较研究


改善土壤水力特性是土壤耕作的重要目的之一。最近对永久带电土壤的研究表明，阳离子对土壤水分渗透有特定的影响。在这项研究中，比较研究了可变和永久带电土壤的土壤水分渗透和土壤团聚体稳定性的特定阳离子效应。研究发现，对于永久和可变带电的土壤，对土壤水分渗透和土壤团聚体稳定性的特定阳离子效应完全不同。对于带电的土壤，比阳离子效应对土壤水分渗透的作用序列为Li+ << K+ < Cs+，这与Li+的阳离子极化序列一致 （0.029 Å3） << K+ （0.88 Å3） < Cs+ （2.56Å3）;但对于带变电荷的土壤，序列变为 Cs+ > Li+ > K+。阳离子浓度对土壤永久带水渗透率（SWIR）影响的顺序依次为SWIR（0.0001 mol/L）、< SWIR（0.001 mol/L）、< SWIR（0.01 mol/L）、< SWIR（0.1 mol/L），而变电荷土壤则变为SWIR（0.1 mol/L）、< SWIR（0.0001 mol/L）≈SWIR（0.01 mol/L）、< SWIR（0.001 mol/L）。两种土壤比阳离子和阳离子浓度对土壤水分渗透的影响差异来自对土壤团聚体稳定性的影响。对于永久带电的土壤，土壤电场决定了土壤团聚体的稳定性。然而，对于带电荷的土壤，除了土壤电场外，渗透压、带正电荷的胶体和金属阳离子的表面反应可能对土壤团聚体的稳定性起关键作用。