An analytic description of field capacity and its application in crop production

Using a range of representative soil types, the analytic FC expressions predicted q and θ within 36% of numerically determined values for t ≥ 0.01 days and Z = 0.3 m or 1.0 m, which is considered sufficiently accurate for most FC applications. The FC expressions showed that all four FC components are important, and that most FC applications have both agronomic and environmental implications. Static FC definitions based on specified matric head or retention curve shape were frequently inaccurate. It was concluded that the FC concept is most appropriately applied in crop production studies by using integrative FC expressions to optimize air and water storage, drainage flux, drainage time, and potential nutrient leaching rate in the crop root zone.