Develop Pedotransfer Functions by Using of Soil Physical and Chemical Properties in Different Depths to Estimate the Saturated Hydraulic Conductivity

Saturated hydraulic conductivity is an important factor in the related issues to water and soil. The aim of this study was to estimate the saturated hydraulic conductivity (Ks) for 280,000 hectares of land in the Northern Rivers Gharasoo - Gorganroud. For this purpose was used data from 188 soil profiles. Available soil information includes some of the physical properties of soil (till the depth 6 m), some of the chemical properties of the soil (till the depth 1.5 m) and some chemical properties of the water in the wells. The aim of the present study was evaluating the effects of combined physical and chemical available parameters from different depths on the accuracy of the models were fitted. To this end, three models were proposed with different inputs. The first model was created by using the chemical properties of water and soil, the second model was developed by using soil physical parameters and third model were created by combining parameters of the two previous models. The results showed that the third model is more accurate and the value of R2, R2adj and RMSE, respectively was, 0.61, 0.56 and 0.34 also ME values for the three models respectively was 0.05, 0.02 and 0.06. Verification test results showed that the average predicted values and the measured Ks in all models, with no significant difference.