Evaluating the performance of concentration-number (C-N) fractal model for separation of soil horizon regarding vertical distribution and 3D models

This study aims to evaluate the efficiency of the concentration-number (C-N) fractal model for discrimination of soil horizon regarding the depth distribution profile. In this regard, soil parameters such as pH, organic carbon content, calcareous mineral content, electrical conductivity and available phosphorus of Ziarat forestland in Golestan Province, north of Iran, has been investigated. The C–N model of all parameters except EC reveals three distinct horizons, while EC indicates 4 horizons. Results of the distribution profile based on fractal thresholds for pH and available phosphorus accurately classified horizons in most of the samples. The result of vertical distribution of EC regarding the fractal method identified horizons correctly except for Z4 and Z7. In addition, horizons of Z1, Z3, Z6, and Z8 have been classified distinctly by using fractal thresholds of organic carbon content in this area. However, vertical distribution of the calcareous mineral content of the study area according to the fractal method was not applicable and soil horizons were not obtainable. In conclusion, based on the combination of results driven by fractal and vertical distribution, the closest model to soil horizons have been created by EC and pH distribution. The 3D model of soil horizon based on thresholds of fractal method shows a SE to NW trend in pH variation from acidic to basic.