Soil particle size distribution (PSD) essentially determines the soil's physical characteristics, including aggregate stability and porosity. Evaluating the PSD of sodic soils altered by reclamation is beneficial to the development of strategies for addressing land degradation. However, it remains unclear how to extract the features of PSD of sodic soils sensitively under gypsum reclamation. In this study, a total of 108 soil samples collected from a reclaimed sodic field were measured for PSD along with other soil properties, including hydraulic conductivity. Almost all the reclaimed sodic soil was measured to be silt loam, which was not obviously different from their original texture. The concentration, uniformity and symmetry of PSD of sodic soils have been quantified by fractal and multifractal geometry methods, in which the multifractal method provided more parameters than the fractal method to characterize the features of PSD more sensitively. The multifractal method offering predictive parameters (i.e., D₁, D₂, α_min and α₀-α_min) was able to significantly (p < 0.05) differentiate the features of PSD. The multifractal results indicated that the heterogeneity of PSD at 0–60-cm depth was increased by reclamation, whereas the major particle size (silt) in these sodic soils decreased, and the combined treatment (i.e., using flue gas desulphurization [FGD] gypsum plus leaching water) created the most heterogeneous PSD. The redistribution of soil particle size caused by reclamation treatments resulted in the improvement of soil physical and chemical properties, showing increased soil aggregate diameter, raised total porosity, enhanced saturated hydraulic conductivity and decreased pH. The findings of this study bring a new opportunity to evaluate the effects of gypsum on the quality of sodic soils from the PSD perspective, which also provides a reference for evaluation of reclamation of other poor soils.

中文翻译：

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土壤粒度分布的多重分形分析评估石膏对钠质土壤质量的影响

土壤粒度分布 (PSD) 基本上决定了土壤的物理特性，包括团聚体稳定性和孔隙率。评估因开垦而改变的钠质土壤的 PSD 有利于制定解决土地退化问题的策略。然而，如何灵敏地提取石膏复垦下钠质土壤的PSD特征仍不清楚。在这项研究中，共测量了从再生钠田收集的 108 个土壤样品的 PSD 以及其他土壤特性，包括水力传导率。几乎所有开垦的钠质土壤都被测量为粉砂壤土，与它们的原始质地没有明显差异。已通过分形和多重分形几何方法量化了钠质土壤 PSD 的浓度、均匀性和对称性，其中多重分形方法提供了比分形方法更多的参数来更灵敏地表征PSD的特征。提供预测参数的多重分形方法（即D ₁ , D ₂ , α _min和α ₀ - α _min ) 能够显着 ( p < 0.05）区分PSD的特征。多重分形结果表明，复垦增加了 0-60 厘米深度 PSD 的非均质性，而这些含钠土壤中的主要粒径（淤泥）减小，联合处理（即使用烟气脱硫 [FGD] 石膏）加上浸出水）创造了最异质的 PSD。复垦处理引起的土壤粒径重新分布导致土壤理化性质的改善，表现为土壤团聚体直径增加，总孔隙度增加，饱和导水率增加，pH值降低。本研究结果为从PSD的角度评价石膏对钠质土壤质量的影响提供了新的契机，也为评价其他贫瘠土壤的复垦提供了参考。