Defining Direct and Indirect Effect of Some Soil Properties on Soil Penetration Resistance

The objective of this study was to determine direct and indirect effects of some soil properties on soil penetration resistance. the experimental field was gridded with 80 m intervals in the e-w and n-s directions, and soil penetration resistance was measured at 72 intersections using a penetrologger. soil samples from upper and lower soil layers were also taken at the same points for determining physical and chemical soil properties. the results of study indicated that the highest direct effect to upper soil layer compaction was sand, silt and clay content and the lowest was bulk density. on the other hand, the highest direct effect to subsoil layer compaction was bulk density and lowest was clay content.