Evaluation of different methods for the prediction of saturated hydraulic conductivity in tilled and untilled soils

The larger the bulk density of the soil, the smaller the saturated hydraulic conductivity (K-s), however, the relationship between K-s and dry bulk density for tilled and untilled conditions is different. K-s is lower in tilled soil than in untilled soil with the same texture at the same bulk density. The purpose of this study was to compare different models for the prediction of K-s for two soil textures under both tilled and non-tilled conditions. We compred two models based on the non-similar media concept (NSMC-0, NSMC-1), a model based on the similar media concept (SMC) and a model based on the Kozeny equation and Poiseuille law for prediction of Ks (KC-1 and KC-2). This study was conducted at two areas with loam and silty clay loam soils under tilled and untilled conditions. It is concluded that the SMC model is not able to predict K-s under either tilled or untilled conditions. Further, the NSMC-0 model, along with an equation to estimate the shape factor, was able to predict K-s versus dry bulk density for tilled soils. According to our study, under untilled conditions, the KC-1 and NSMC-1 models, and under tilled conditions, the NSMC-1 and NSMC-0 models, predicted K-s accurately. It is concluded that the NSMC models together with the optimized Kozeny-Carman models could reliably be used to predict K-s in different soil textures.