Comparison of Fitting Quality and Changes Trend of Moisture Curve Parameters of Mualem-Van Genuchten Model at Different compaction Treatments of Sandy Loam and Clay Loam Soils

ABSTRACT: Soil hydraulic properties including soil water characteristics curve and hydraulic conductivity are two important properties to determination of water movement in soil. The aim of this study was to evaluation of fitting quality of Mualem-Van Genuchten model on moisture curve and comparing in two soil texture classes (sandy loam and clay loam) and in different compaction treatments. Samples were collected from 0-10cm depth and Compaction created by proctor in six replication and four levels including C0 (control), C1, C2 and C3 by increasing in soil bulk density with the ratio of 5, 10 and 15%, respectively. Mualem-Van Genuchten model using RETC software were fitted on moisture-suction data obtained from pressure plate. Fitting quality of considered model achieved by R2 and RMSE calculation. RMSE in sandy loam soil had no change compared to control. But clay loam soil had increasing trend in terms of RMSE. Due to little changes of model in sandy loam in all treatments compared to clay loam, the use of this model in light textured and field compaction status was recommended.