ACTUAL WATER USE OF YOUNG DATE PALM TREES AS AFFECTED BY AMINOLEVULINIC ACID APPLICATION AND DIFFERENT IRRIGATION WATER SALINITIES

The Arabian Gulf countries are facing unprecedented water management challenges owing to limited water resources and salinization of the soil. Date palm trees represent a crucial socio-economic asset in the region. Improving water productivity and tolerance to salinity are the most viable options. A split plot experiment was conducted on 4-year-old date palm trees in concrete lysimeters. The objective was to study the effects of aminolevulinic acid (ALA) and different irrigation water salinities (EC) on actual water use (ET) and irrigation efficiency (IE). Low: < 1, medium: 12-15 and high: 18-20 (dS m?(1)) EC were used as main plots while zero and 5 ml per tree of ALA represent the subplots. Data were collected during the period between June 2016 and September 2017. Results indicated that ALA application significantly increased tree ET by about 7%. Medium and high EC levels masked the effect of ALA on ET. EC significantly reduced ET by about 70 and 83% for high and medium EC respectively. The highest ET was obtained under low EC with ALA. Highest IE (63%) was obtained under low EC with ALA, followed by 48% for low EC without ALA. All ALA treatments resulted in higher IE compared with no ALA. (c) 2020 The Authors. Irrigation and Drainage published by John Wiley & Sons Ltd on behalf of International Commission for Irrigation and Drainage