Assessing The Soil Water Characteristic Curve (SWCC) Models

Abstract

Investigating the soil hydraulic properties such as wilting point and field capacity is very important in studying and modeling water and solute in soil. Due to the spatial and temporal changes of these characteristics, recent studies have led to the development of indirect methods to estimate the soil properties. In this study, 10 models were used in order to estimate the soil water characteristics curve (SWCC) in soils of Clay, Clay loam, and Sandy loam; hence, to choose the best model. For this purpose, first the SWCC for the studied soils was calculated using pressure plate and then, models were fitted to the experimental data. Saturated hydraulic conductivity was measured in the laboratory and it was estimated by Rosetta model. The results showed that except for Campbell and Russo, all models presented the appropriate performance in estimation of SWCC. Moreover, Biexponential model fitted well with the best performance compared with other models in soils of Clay, Clay loam, and Sandy loam with the sum of the squared residuals (SSR) of 5×10-4, 2×10-4, 1×10-4 respectively, RMSE: 0.013, 0.015, and 0.015 cm3/cm3 respectively and R2: 0.997, 0.995, and 0.998 respectively. SSCBDTH331500 method in Rosetta model predicted the amount of saturated hydraulic conductivity with high accuracy. The results of this research will help to provide the optimum method for estimating SWCC.

Keywords

• soil water
• swcc
• hydraulic conductivity
• saturated soil