Evapotranspiration of Cherry Tomatoes under Drip Irrigation with Fish Effluent in Hydroponic System

Cherry tomatoes has been introduced as a valuable source of vitamin and most widely consumed staple food in Iran. In other hand, the integration of aquaculture with agriculture appears to be an excellent way of saving water, disposing aquaculture effluents and providing additional fertilizer to the crop. It is also necessary to optimize irrigation water requirement by estimating crop evapotranspiration correctly enough to avoid wastage of water. The aim of this study was to determinate the evapotranspiration of cherry tomatoes (Sweet Million cultivar) under drip irrigation with fish effluent in hydroponic system. The greenhouse experiment was carried out in a split-plot design with three different irrigation water qualities (well water with nutrient solution, fish effluent with nutrient and fish effluent without any nutrient), four mediums (perlite 100%, perlite 40%-cocopeat 60%, perlite 60%-cocopeat 40% and soil) in four replications at Bajgah, College of Agriculture, Shiraz University. The reference evapotranspiration (ETO) was calculated by using FAO Penman-Montith method. The meteorological data was recorded inside the greenhouse every day. The crop evapotranspiration (ETC) was determined using water balance method and compared with the dual crop coefficient method. The highest and lowest cherry tomatoes’ productivity was in soil (0.755 kg plant-1) and perlite (0.181 kg plant-1). The seasonal ETO was 570 mm and the lowest and the highest of ETO were 1.53 mm d-1 (July) and 4.44 mm d-1 (October) respectively. The ETC were 613.14 mm (balance method) and 569.94 (dual crop) respectively in soil culture. Results revealed that the ETC was underestimated 8%. The calculated ETC was lower in other mediums than soil.