1 23 Irrigation Science ISSN 0342-7188 Volume 33 Number 4 Irrig Sci (2015) 33:277-287 DOI 10.1007/s00271-015-0465-5 The influence of irrigation level on olive tree nutritional status Isaac Zipori, Uri Yermiyahu, Ran Erel, Eugene Presnov, Inna Faingold, Alon Ben-Gal & Arnon Dag