The influence of irrigation level on olive tree nutritional status

While modernization of olive cultivation has recently lead to vast expansion of fully irrigated orchards, characterization of olive tree nutritional status remains based on knowledge gleamed from rain-fed orchards. In the present study, the effect of irrigation level on olive tree nutritional status was investigated in Israel over 4 years on two cultivars and in two locations characterized by differences in soil, tree age, management history, fertilizer application and irrigation water quality. Diagnostic leaves, sampled in July, were evaluated as indicators of nutritional status. Leaf nitrogen concentration was not affected by irrigation level. Leaf phosphorous and potassium concentrations increased with increasing irrigation level. Leaf calcium, manganese and iron tended to decrease with irrigation, while magnesium, sodium and zinc concentrations were not generally affected by irrigation level. Leaf boron and chloride concentrations increased with increasing irrigation when their concentration in irrigation water was relatively high. Leaf nutrient concentration was influenced by cultivar. The results presented in this study emphasize a strong link between irrigation level and the nutritional status of olives for some nutrients and no association for others. These findings should aid in developing distinct fertilization recommendations for fully irrigated olives, different from those developed and used for rain-fed or supplemental-irrigated orchards.