Department of Plant Sciences

Optimal potassium nutrition is essential to maximize olive tree production. In Tunisia, olive trees are mainly conducted under rainfed conditions and subjected to water and nutrient deficits. An experiment was established in semi arid region to study the response of olive tree to potassium mineral nutrition using potassium sulphate in reference to Control. Potassium was supplied by foliar spray and soil spreading at two levels. Foliar treatments were 50 and 100% of tree requirement. For soil spreading, 100% and 200% of the tree needs were applied. After five of experiment, yield was significantly higher for 100% foliar spray than the control. Leaf mineral analysis revealed a significant increase of K foliar content in response to K supply. Foliar nutrition at 100% of tree needs improved the cumulative yield and olive quality. An increase of average fruit weight, pit ratio was observed for foliar spray treatment. However, oil quality seems to be unaffected with insignificant differences of poly phenols content and fatty acid composition.