Soil structure, which refers to aggregates and pore characteristics, reflects the spatial arrangement of soil particles and is a key component for crop yield and soil health. Well-formed soil structure has favorable pore size distribution, which supports soil water flow and retention and healthy plant growth. Compost and biochar, important organic amendments, have a potential to influence soil structure, but their effects on specific soil types and soil properties have not been fully investigated. The main objective of this study was to investigate the impact of the additions of compost and/or date palm biochar on selected soil water indicators and pore size distribution of a loamy sand soil using disturbed soil samples. Statistical parameters of pore size distribution properties such as SD, kurtosis, skewness, modal diameter (d_mode), median diameter (d_median), and mean diameter (d_mean) as well as plant available water capacity (PAWC), available soil water capacity (ASWC), saturated soil water content, and measured saturated hydraulic conductivity (K_sat) were measured and evaluated. The results showed that the d_mode, d_median, d_mean, SD, skewness, and kurtosis values for untreated soil (control) were 31.6 μm, 25.8 μm, 23.5 μm, 3.3, −0.16, and 1.14, respectively. Biochar, compost, and a mixture of biochar–compost additions to a loamy sand soil significantly reduced d_mode, d_median, and d_mean values in comparison with nonamended soil. Application of these amendments increased PAWC and ASWC and reduced K_sat of the loamy sand soil, significantly. Biochar–compost mixture has the most significant effect on improving soil water retention and PAWC.

中文翻译：

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生物炭和堆肥改良剂对壤质砂土土壤水分和孔径分布的影响

土壤结构是指团聚体和孔隙特征，反映了土壤颗粒的空间排列，是作物产量和土壤健康的关键组成部分。良好的土壤结构具有良好的孔径分布，有利于土壤水分的流动和保持以及植物的健康生长。堆肥和生物炭是重要的有机改良剂，具有影响土壤结构的潜力，但它们对特定土壤类​​型和土壤性质的影响尚未得到充分研究。本研究的主要目的是使用扰动的土壤样品研究添加堆肥和/或枣椰树生物炭对选定的土壤水分指标和壤质沙土的孔径分布的影响。孔径分布特性的统计参数，如 SD、峰态、偏度、模态直径（d _mode )、中值直径 ( d_中值) 和平均直径 ( d_均值) 以及植物有效水容量 (PAWC)、土壤有效水容量 (ASWC)、饱和土壤含水量和测量的饱和导水率 ( K _sat ) 进行测量和评估。该结果表明，d_模式，d_中位数，ð_意味着，SD，偏度和峰度为未处理的土壤（对照）的值分别为31.6微米，25.8微米，23.5微米，3.3，-0.16，和1.14，分别。生物炭、堆肥和在壤质沙土中添加生物炭-堆肥的混合物显着降低了d_模式、d_中值和d_平均值与未修正土壤相比。这些改良剂的应用显着增加了 PAWC 和 ASWC，并显着降低了壤质沙土的K _sat。生物炭-堆肥混合物对提高土壤保水性和 PAWC 效果最显着。