Effect of Soil Compaction on Soil Pore Structure Using X-ray Computed Tomography and Prediction of Pore Network Characteristics‏

Abstract

Purpose; The pore structure of soil is significantly affected by compaction, a consequence of increased agricultural mechanization. We hypothesized that texture and soil organic carbon (SOC) would determine baseline pore architecture, influencing how compaction alters pore volume, connected, and distribution. This study investigated the effects of soil compaction on pore structure using X-ray computed tomography (XCT) and prediction of pore network characteristics. Methods; Soil samples were collected from the Loess Plateau in China to produce disturbed soil samples at five bulk density levels to simulate different levels of compaction. Samples were analyzed for particle size distribution (PSD) and SOC. XCT were used to scan the compacted soil samples and visualize and analyze the three-dimensional pore structure via Avizo software. Multiple linear regression (MLR) was employed to predict pore network characteristics, with optimal models selected based on statistical criteria. Results; Indicated that soil texture and SOC content significantly influence the rate of change in pore size and number with increasing soil compaction, with fine texture and higher SOC content resulting in faster changes in pore structure compared to coarse texture. Most pores, in terms of number and volume, fall within the 0-100 μm range. In addition, similar pore size distributions were detected in two soil types for loam and clay loam. Conclusion; MLR models predict pore network characteristics from soil properties (silt + clay + SOC), the best combination of input variables for prediction. The predictive models can assist in implementing sustainable soil management practices that mitigate the adverse impacts of compaction on soil health and agricultural productivity.