Field‐scale evaluation of infiltration parameters from soil texture for hydrologic analysis

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Abstract
Recent interest in predicting soil hydraulic properties from simple physical properties such as texture has major implications in the parameterization of physically based models of surface runoff. This study was undertaken to (1) compare, on a field scale, soil hydraulic parameters predicted from texture to those derived from field measurements and (2) compare simulated overland flow response using these two parameter sets. The parameters for the Green‐Ampt infiltration equation were obtained from field measurements and using texture‐based predictors for two agricultural fields, which were mapped as single soil units. Results of the analyses were that (1) the mean and variance of the field‐based parameters were not preserved by the texture‐based estimates, (2) spatial and cross correlations between parameters were induced by the texture‐based estimation procedures, (3) the overland flow simulations using texture‐based parameters were significantly different than those from field‐based parameters, and (4) simulations using field‐measured hydraulic conductivities and texture‐based storage parameters were very close to simulations using only field‐based parameters.