Problems & Considerations in Determining Physical Properties of Horticultural Substrates

The establishment of research protocol for horticultural substrates must include the measurements of physical and hydraulic properties. Both empirical and mechanistic approaches must be utilized in protocol development. The steps in establishing a protocol should be: 1) the development of standard definitions for properties and terms, 2) development of a mechanistic framework based on modeling, and 3) development of procedures for data collection. Pore space diagnostics and available water determinations must be reexamined to more appropriately describe these terms. The concept of hydraulic status is introduced as one diagnostic protocol for physical and hydraulic properties.