Influence of Deficit Irrigation Using Saline Water on Yield of Tomato under Two Irrigation Systems
Ahmed F. Saad , Adel. A. Shalaby, and Ahmed. M. Mokhtar
Field experiment was conducted in calcareous soil at Maryout Experimental Station Farm, Desert Research Center, Egypt to investigate the influence of deficit irrigation water using highly saline water on yield and water productivity of tomato (Lycopersicon esculentum, mill., cultivator 888) under drip and gated pipe irrigation systems. The tomato plants were subjected to 3 deficit irrigation depths (100, 75 and 50 % of ETc) throughout 3 growth stages (development, flowering and harvesting) using highly saline water of 9.15 dSm-1 plus control treatment. The tomato plants were irrigated by the full irrigation (100 % ETc) during the whole growth season using slightly saline water of 2.80 dSm-1. The reduction percentage in tomato fruit yield ranged between 9.9 to 41.5 % and 9.1 to 30.9 % at treatment T2100 – D (plants irrigated by the full irrigation: 100% of ETc) using highly saline water throughout the development stage then irrigated by the same water depth using slightly saline water (agricultural drainage water), throughout the other growth stages and treatment T950 – F (plants irrigated by deficit irrigation depth of 50% ETc using highly saline water, 9.15dSm-1. The flowering growth stage of tomatoes was the highest stage influenced to deficit irrigation using highly saline water especially at deficit irrigation of 50 % ETc. The tomato fruit yield under drip irrigation system was significantly higher than that obtained under gated pipe irrigation system. The highest value of crop water productivity (CWP) was obtained at control treatment and the lowest value was obtained at treatment T950-F. The highest and lowest values were 9.5 and 5.56 kg/m3 and 8.23 and 5.69 kg/m3 under drip and gated pipe irrigation systems, respectively. A significant polynomial relationship between tomato fruit yield (Y), kg/m2, and applied irrigation water (AW), m3/m2 was given with R2 0.78. The predicted maximum yields were 18.54 and 11.63 kg/m2 and the corresponding calculated the applied irrigation water were 2.57 and 2.59 m3/m2 under drip and gated pipe irrigation systems, respectively. The crop response factor (Ky) using highly saline water under drip and gated pipe irrigation systems were 1.090 and 0.743, respectively.
Keywords: deficit irrigation, saline water, crop water productivity, drip irrigation and gated pipe.