Erel, R., Institute of Soil, Water and Environmental Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Negev, Israel, Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Kerem, Z., Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Ben-Gal, A., Institute of Soil, Water and Environmental Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Negev, Israel
Dag, A., Institute of Plant Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Negev, Israel
Schwartz, A., Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Zipori, I., Institute of Plant Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Negev, Israel
Basheer, L., Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Yermiyahu, U., Institute of Soil, Water and Environmental Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Negev, Israel

The influence of macronutrient status on olive oil properties was studied for three years. Data were analyzed by a multivariate model considering N, P, K, and fruiting year as explanatory factors. Oil quality parameters were primarily associated with N concentration in leaves and fruits which increased with N in irrigation solution. The effect of P on oil quality was mainly indirect since increased P availability increased N accumulation. The potassium level had negligible effects. The oil phenolic content decreased linearly as a function of increased leaf N, indicating protein-phenol competition in leaves. The overall saturation level of the fatty acids decreased with fruit N, resulting in increased polyunsaturated fatty acids. Free fatty acids increased with increased levels of fruit N. High fruit load tended to reduce fruit N and subsequently improve oil quality. The effect of N on oil properties depended solely on its concentration in leaves or fruits, regardless of the cause. © 2013 American Chemical Society.