RESPONSE OF OLIVE TREES TO IRRIGATION WITH SALINE WATER
Water demand for irrigation is increasing in olive orchards due to enhanced yields and profits. Because olive trees are considered moderately tolerant to salinity, irrigation water with high salt concentration is often used without considering the negative effects on olive tree growth and yield. We studied salt effects in mature olive trees in a long term field experiment (1998-2006). Eighteen-year-old Picual olive trees were cultivated under drip irrigation with saline water composed of a mixture of NaCl and CaCl2. Three irrigation regimes (no irrigation, considering soil water content or without considering it and adding a 20% more as a leaching fraction) and three salt concentrations (0.5, 5 or 10 dS m-1) were applied. Growth parameters, leaf and fruit nutrition, yield, oil content and fruit characteristics were annually studied. Annual leaf nutrient analyses indicate that all nutrients were between the adequate levels. After eight years of treatment, salinity did not affect any growth measurement and leaf Na+ and Cl- concentration were always below the toxicity threshold of 0.2 and 0.5%, respectively. Annual and accumulated yield, fruit size and pulp:stone ratios were not either affected by salts. However, oil content increased linearly with salinity, with differences observed since 2001. Soil salinity measurements showed that there was no accumulation of salts in the upper 30 cm of the soil (where most of the roots are present) because of leaching by rainfalls at the end of the irrigation period. Results suggest that a proper management of saline water, supplying Ca2+ to the irrigation water, using drip irrigation until winter rest and enough rainfalls leach the salts, and growing a tolerant cultivar, can allow using high saline irrigation water for a long time without affecting growth and yield in olive trees.
Melgar, J.C., Mohamed, Y., Serrano Castillo, N., García-Galavís, P.A., Navarro, C., Parra, M.A., Beltrán, G., Benlloch, M. and Fernández-Escobar, R. (2012). RESPONSE OF OLIVE TREES TO IRRIGATION WITH SALINE WATER. Acta Hortic. 949, 279-282
Olea europea, salt tolerance, drip fertigation, calcium supply