Mohammad Gohardoust - University of Arizona, Department of Soil, Water and Environmental Science, Tucson, AZ

Ty P.A. Ferré - University of Arizona, Department of Hydrology and Water Resources , Tucson, AZ

Markus Tuller - University of Arizona, Department of Soil, Water and Environmental Science, Tucson, AZ; University of Arizona, Department of Hydrology and Water Resources , Tucson, AZ

Over the last decade there has been a dramatic shift in global agricultural practice. The increase in human population, especially in underdeveloped arid and semiarid regions of the world, poses unprecedented challenges to production of an adequate and economically feasible food supply to undernourished populations. As a response to these imminent challenges and demands, soilless greenhouse production systems are regaining increased worldwide attention. Though there is considerable recent empirical and theoretical research devoted to specific issues related to control and management of soilless culture production systems, a comprehensive approach that quantitatively considers all relevant physicochemical processes within the growth substrates is lacking. To overcome these shortcomings, we applied thorough physicochemical characterization of commonly used greenhouse substrates in conjunction with state-of-the-art numerical modeling (HYDRUS-3D) to not only optimize management practices (i.e., irrigation frequency and rates, fertigation, container size and geometry, etc.), but to also “engineer” optimal substrates by mixing organic (e.g., coconut coir) and inorganic (e.g., perlite, pumice, etc.) base substrates and modifying relevant parameters such as the particle (aggregate) size distribution.