Oxyfertigation:: A new technique for soilless culture under Mediterranean conditions

Due to high root density and the relative confinement of the growing medium in soilless culture, rhizosphere oxygen levels drop at an accelerated rate. Conditions may arise that disturb root respiration when the temperature and salinity of the substrate solution are high, as frequently occurs in soilless culture in the agroclimatic context of the Mediterranean coast. Oxygen is the most important macromineral for plants. However, making sure oxygen is available to roots has not received all the attention it deserves. Ensuring substrate aeration is optimal, based on the characteristics of the substrate and careful management of irrigation, is not always enough to guarantee root comfort in soilless culture under Mediterranean coastal conditions. The oxyfertigation technique has been developed to improve rhizosphere oxygen availability in plants grown using soilless culture, and consists of supplying dissolved oxygen in the irrigation water at oversaturated concentrations using fertigation equipment. This article describes the oxyfertigation technique and presents some of the results of different soilless-culture experiments in which this technique was used and which illustrate its agronomic effectiveness.