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

It has been established for decades that soil water field capacity (FC) includes four main components: drainage rate or flux (q), drainage time from saturation (t), soil water content in the drained zone (θ), and drainage depth (Z). Despite this, rather little work has been done to incorporate these components into analytic FC expressions, or to determine how such expressions are best used in applications of the FC concept. The primary objectives of this study were: i) develop analytic FC expressions that account for the four components of FC; ii) determine the accuracy of the FC expressions using numerical simulations of soil profile drainage from saturation; and iii) illustrate how analytic FC expressions might be used to optimize air, water and nutrient dynamics in field crop production.