Application of microscopic features of soil pores in the assessment of soil physical quality

Researchers consistently seek methods that minimize data requirements and decrease soil quality assessment costs. Soil pores are recognized as indicators of soil physical quality due to their environmental sensitivity. This study identified key parameters related to soil pores and physico-chemical properties to assess their potential as indicators of soil physical quality. Conducted between 2020 and 2022 at the University of Tehran's Soil Sciences Department Micromorphology Laboratory, the study used image analysis to determine the parameters related to pores resulting from 126 experimental units, including ammendments, removals and disruptive experimental treatments and affected by 22 cycles of wetting and drying which were determined in two types of soils, sandy loam and silty clay. Parameters included sphericity, elongation, area, and compactness. The first two principal components (PC1 and PC2) represent more than 70% of the variations in the studied soils. Parameters like sphericity (81% and 80% correlation with PC1 and PC2) and elongation (77% and 83% correlation with PC1 and PC2) in loamy sand, and elongation (53% and 87% correlation with PC1 and PC2) and pore area (48% and 68% correlation with PC1 and PC2) in silty clay loam were identified as quality indicators. Comparing soil quality based on pores in different treatments with control showed 32% and 18% differences in loamy sand and silty clay loam, respectively, demonstrating indicator efficacy in reflecting soil quality changes. The microscopic features of pores that possess fractal properties were successfully utilized in this study for assessing soil quality. Based on this method, it is possible to employ this approach for determining soil quality on a field scale.