Assessment of different ETO-Dependent Irrigation Levels for Pomegranate on Saving Water and Energy and Maximizing Farm Income

Abstract

Field experiments were conducted on drip–irrigated pomegranate (Punicagranatum L.) trees grown in a private farm at kilometer 76 Cairo/Alexandria Desert Road, Egypt during the 2016 and 2017 growing seasons. The site represents newly reclaimed sandy soil at the west of Nile Delta region. The objectives of this study were to evaluate the effect of different ETo-dependent irrigation levels on amounts of applied irrigation water, water consumptive use, fruit yield and its components, fruit quality, water use efficiency, water productivity, and to develop a local pomegranate crop coefficient (Kc) and yield response factor (Ky) under the experimental conditions, as well as the effect on saving energy and increasing farm income. Four irrigation treatments (120, 100 and 80, and 60% ETo) were compared to farmer irrigation practice. The experimental treatments were laid out in strip plot design with four replicates. Results indicated that distribution uniformity values, conducted at the beginning of each season, were 88 and 90 % in 1st and 2nd seasons, respectively. The 2–season average amounts of applied irrigation water for the 120, 100, 80, and 60% ETo and farmer treatment were 13520, 11270, 9020, 6760, and 18075 m3 ha-1, respectively. Average values of total fruit yield were 40.2, 38.6, 36.9, 23.8, and 31.8-ton ha-1 for the same respective treatments. The highest fruit diameter and weight were produced from irrigation with 120% ETo. The Kc values for the 120% ETo irrigation treatment were 0.14-0.45, 0.45-0.79, 0.79-1.05, and 1.05-0.76 for initial, crop development, mid- and late-season growth stages, respectively. Results showed that pomegranate yield response factor (Ky) was 0.81 indicating that pomegranate trees are moderately tolerant to water stress. Application of the proposed irrigation treatments reduced consumed energy by values varied from 25 to 62% compared with farmer irrigation. The 2-year average net income values of the 120, 100, 80, and 60% ETo irrigation treatments were 117, 106, 91, and 3% higher than that of farmer practice. Under the experiment circumstances it could be concluded that, irrigating pomegranate trees at 80% ETo level saves 9055 m3/ha of applied irrigation water and 50% of the electric energy In addition, the highest figures of water use efficiency (4.7 kg fruits/m3 water consumed), water productivity (4.1 kg fruits/m3 water applied), and net income (91% more), were achieved compared with farmer practice.