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The potential of saline and residual water use in olive growing

Chartzoulakis, K. S.
Acta horticulturae 2014 no.1057 pp. 257-273
absorption, climate change, cost effectiveness, crop yield, cultivars, fatty acid composition, freshwater, gas exchange, genotype, irrigation scheduling, irrigation water, leaching, leaf abscission, leaves, lipid content, mixing, nitrogen, nutrients, olive oil, olives, phenols, phosphorus, plant growth, population growth, potassium, production technology, roots, salinity, salt tolerance, sodium, sodium chloride, soil amendments, soil water, stomatal movement, trees, wastewater, water quality, water supply, Argentina, Australia, California, Chile, Mediterranean region, New Zealand, Peru, South Africa, Uruguay
Olive is a major tree crop in the Mediterranean region, although the last decades, olive culture is developing outside this region, from South America (Argentina, Chile, Peru, Uruguay) and United States (California) to Australia and New Zealand and South Africa, using mainly intensified production systems. Irrigation of olives with low quality water (saline, reclaimed, etc.) is increasing worldwide due to negative effects of population growth and climate change on the availability and quality of existing fresh water supplies. Olive tree is considered moderately tolerant to salinity; however, under certain irrigation practices high saline irrigation water (up to 10 dS/m) for a long time can be used without affecting growth and yield. High salinity inhibits plant growth and affects gas exchange properties of olive leaves. There are differences in salt tolerance among cultivars associated with ion exclusion and retention of Na+ and Cl- in the root. The mechanism is located within the roots and prevents salt translocation, rather than salt absorption. Besides that, osmotic adjustment, stomatal closure and leaf abscission appear to play a role. High salinity generally reduces olive yield. Salinity increases or does not affect oil content of the fruit, although the extent of this reduction changes with cultivar. Furthermore, NaCl salinity induces changes in fatty acid composition and increases the total phenol content of olive oil. Potential and cost effective source of irrigation water in olive-growing areas is the reuse of reclaimed wastewater, under certain conditions. Amongst the components of such water are essential nutrients for olive growth and production such as nitrogen, phosphorus and potassium. Management practices for using low quality water for irrigation of olives includes proper irrigation scheduling (amount of water and interval), efficient leaching (amount and timing), proper irrigation method, blending or cyclic use of irrigation water of different quality, using water or soil amendments and selection of salt tolerant genotypes.