Two foliar potassium nitrate sprays effectively increased K content in K-deficient olive plants

The aim of this research was to study the effect of factors such as leaf age, salt type and concentration, number of foliar applications, and the nutritional status on the efficiency of foliar applications of potassium (K) in olive plants. The results obtained indicate that foliar applications of K effectively increased K content in K-deficient olive plants, and that foliar applications might be more effective on young leaves. Two foliar applications of KNO₃ or the equivalent of other salts are enough to increase leaf K concentration. The leaf K concentration for the KNO₃ treatment was 27 % higher than the control, an increase of 0,14% dry weight was found. The KNO₃ treatment showed also the greatest plant dry weight of 6,38 g, although this was not significantly different from the control treatment (6,02 g).