Biochar and compost amendment impacts on soil water and pore size distribution of a loamy sand soil

Abstract 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.