DESIGN AND IMPACT OF USING TRICKLE IRRIGATION SYSTEM FOR GREENHOUSES IN DELTA REGION IN EGYPT

<i>Analysis and hydraulic calculations are directed to optimize a suitable design of low pressure gravity-fed water systems for greenhouses and smallholder farms. The experiment was conducted to analyze the impact of key design factors such as the required head (2, 3, 4 and 5 m), emitter spacing [(0.3, 0.6, 0.9 and 1.2 m for in–line non-pressure compensated (INPC) emitters and 0.4, 0.7, 1.0 and 1.3 for on-line pressure compensated (OPC)], discharge capacity and emitter type (INPC and OPC) and their effect on the maximum lateral length (MLL) which was defined as the length with flow variation that is less than or equal to 5% in a low-pressure gravity fed trickle system. INPC emitters had the highest effect of the head on the maximum lateral length (MLL) at all emitter spacing under study. Spacing of 1.2 and 1.3 m for the INPC and OPC emitters, respectively, had the highest effect on the MLL. However, the lowest values of MML were 11.96 and 17.53 m, which were for 0.3 and 0.4 m spacing in INPC and OPC emitters, respectively. Also, the combine model of variables without their interactions has indicated that INPC emitters perform the highest MLL and the other variables in the model were significant. Such equations could be used to decide the MLL for a given spacing under the available head of the water supply system. In both NPC and INPC emitters, increasing the head level increased total tomato yield and there were significant decreasing in yield by increasing emitter spacing, where maximum yield was 43.6 ton/ha at 5 m head for INPC emitters and 44.4 ton /ha at 4 m head for OPC emitters with emitter spacing 0.3 and 0.4 m respectively.