Pedotransfer functions for the United States

Abstract

This chapter presents pedotransfer functions (PTFs) that have been developed from national databases. The PTFs presented are for water retention and saturated hydraulic conductivity. PTFs for water retention take one of two forms: PTFs that predict water retention at specific matric potentials and PTFs that predict the parameters of water-retention models. The two most frequently estimated water contents are those corresponding to soil water potentials of −33 and −1500 kPa, primarily because they are commonly measured and have commonly been referred to as “field capacity” and “wilting point,” respectively. The chapter tabulates equations developed from regression analysis that estimate soil water retention at specific water potentials using soil properties, soil properties and water retained at −1500 kPa, and soil properties and water retained at −33 and −1500 kPa.