Evapotranspiration of cherry tomatoes under drip irrigation with fish effluent in hydroponic system

Abstract

Cherry tomatoes have been introduced as one of the main nutritious greenhouse products, valuable source of vitamin and most widely consumed staple food. 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 necessary to optimize irrigation water requirement by estimating crop evapotranspiration correctly enough to avoid wastage of water. The aim of this study was to determine the evapotranspiration of cherry tomatoes ('Sweet million') under drip irrigation with fish effluent in hydroponic system. The greenhouse experiment was carried out in a split-plot design with three irrigation water qualities (well water with nutritious solution, fish effluent with nutrients and fish effluent without any nutrients), four media (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-Monteith 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 media than soil.