evaluation of ankeny and weir equation estimating hydraulic parameters using disc infiltrometer

abstract disc infiltrometer is one of those devices that used in recent years in measurement of hydraulic conductivity of entire soil. in order to analyze the data taken by disc infiltrometer a variety of methods based on wooding’s base analyze have been introduced. the objective of this study was to compare the performances of ankeny and weir methods for predicting soil hydraulic properties using disc data. the study was conducted using a 10 cm radius disc infiltrometer in three different soil texture. the water infiltration was measured for silty loam soil using 15, 10, 7, 3, 1 cm tensions, for loamy sand using 10, 7, 5, 3, 1 cm tensions, and for sandy soil using 30, 25, 21, 17 cm tensions, respectively. the average calculated sorptive number was 0.065, 0.175, and 0.192 cm-1 for loamy sand, sandy, and silty loam soils, respectively. all the unsaturated- saturated hydraulic conductivity coefficients obtained for three soil textures using ankeny analyze were bigger than the values obtained using modified weir equation so that the predicted saturated hydraulic conductivity coefficients using ankeny analyze for sandy loam soil 7.5%, for silty loam soil 29%, and for sandy soil 45% were greated than weir estimates.