AN APPROACH TO MODELING AIR AND WATER STATUS OF HORTICULTURAL SUBSTRATES

Abstract

There have been numerous investigations into the hydraulic properties of porous substrates used as root media for plant production in containers. Much of the discus-sion has focused on defining the parameters necessary to effectively describe this air and water status. The quantity of air and water is the result of physical influences of the medium, container geometry and extent of root development. Five container state parameters have been developed to describe the air and water status of the particular medium/container/plant combination at drainage equilibrium: total porosity, container capacity, air space, available water, and unavailable water. Empirical methods and mathematical procedures were combined to determine these parameters. Container geometry had a pronounced effect on the air and water status of substrates tested. An overall conceptual model is presented to help describe the overriding effects of cultural practices on air and water content of container media.