The objectives of the present study were to examine the effect of the irrigation frequency applied to different substrates and their mixtures and the effect of the containers height on the dynamic of water content and temperature of the growing medium and on the yield and quality of tomato (Lycopersicon esculentum Mill.) as a model plant. An experiment was conducted in a greenhouse at Ramat Negev, Israel. The studied variables were irrigation frequency, type of substrate and container height. Treatments included high and low irrigation frequencies given to three substrates: Tuff, Coir and Tuff/Coir (70%/30% volume basis). Each combination of irrigation frequency and type of substrate was tested in two container heights, 30 cm and 15 cm at a constant volume. Higher irrigation frequency reduced the amplitude of water content in all measured substrates. The physical properties of the substrates had considerable effect on the substrates' moisture and the amplitudes between the minimum and maximum values. The dynamic of water content in the growth substrate was controlled by irrigation frequency, the height of the container and by the hydraulic properties of the substrate. Water availability from surface to the bottom of the containers is higher in short than tall containers but the short containers are suspected to anaerobic conditions. Irrigation frequency and the substrate type had no considerable effect on temperature. The temperature of the upper layer of a container with substrate fluctuates and is more affected by the air temperature than the lowest layers, thus taller container should be less affected by air temperature. The total yield and especially the high quality yield were bigger in tall than short container, probably due to better aeration. Overall, the optimal irrigation frequency for available water is affected by the type of substrate and the height of the container.
Keywords: Water content, Temperature, Container Height, Moisture Gradient, Fruit Yield, Blossom End Rot
ISHS Acta Horticulturae 1321: III International Symposium on Soilless Culture and Hydroponics: Innovation and Advanced Technology for Circular Horticulture