On the Description and Determination of Soil Water Field Capacity

The concept of soil water “field capacity” (FC) has existed for about 100 years, and is widely used in the geosciences for estimating diverse entities such as, plant-available air and water capacities, soil resilience to weather extremes, soil physical quality, potential for deep drainage of soil water, risk for greenhouse gas generation, and risk for leaching losses of nutrients and hazardous contaminants.

Although FC may be conceptually straightforward with definitions as simple as “maximum soil water held against gravity”, ten decades of research and application have shown that FC is actually rather complex with time, depth, porosity, water content, permeability, hydraulic gradient, and drainage flux components.

This presentation will review the primary elements of FC, show various ways that FC can be determined, and illustrate the impacts that calculation method and soil hydraulic properties can have on FC values.