PEDOTRANSFER FUNCTIONS FOR VARIABLE ALLUVIAL SOILS IN SOUTHERN OHIO

A grid sampling pattern of 108 sample locations at distances ranging f rom 15 to 122 m was used to develop a baseline characterization of soi l physical and hydrological properties in a 40 ha field. Statistical d istributions of silt and sand were nor normal. Coefficients of variati on of sand, silt and clay contents were 59%, 18% and 25%. Pedotransfer functions (PTFs) were developed using indicator variables to separate the data into four textural classes (silty clay loam, silt loam, loam and sandy loam), This separation normalized the distributions of sand and silt contents, improving the data for use in development of PTFs. The resulting equations improved the prediction of the dependent vari able (field capacity, permanent wilting point, available water capacit y, percentage of water stable aggregates, or log of saturated hydrauli c conductivity) from the five independent variables sand, silt, clay, organic matter content and bulk density, and suggested texture-specifi c interrelationships between the variables.