In the cultivation of citrus fruits, foliar fertilisation plays an important role.
Even if the soil is optimally supplied with nutrients, the tree's needs are not always satisfied. Many factors limit the availability and uptake from the soil, e.g. high pH values for trace elements and low pH values for main and secondary elements, drought, cool weather, soil compaction, competition and antagonisms (interactions) between the elements.
One of the deficiency symptoms most commonly shown by citrus leaves is iron chlorosis. Iron deficiency is manifested by yellowing of the youngest leaves with dark leaf veins. Early and regular foliar fertilisation with Lebosol®-HeptaIron provides an effective solution here.
Even a good availability of calcium in the soil is no guarantee for a sufficient supply of the fruit, due to the peculiarities of calcium transport in the plant. Therefore, repeated calcium foliar applications with Lebosol®-Calcium-Forte SC (calcium formate as a particularly compatible calcium source) are necessary. Lebosol®-Calcium-Forte SC provides an additional supply of manganese and zinc.
Phosphorus and potassium have a positive effect on the colouring of the fruit, so that with several foliar sprays from fruit set onwards with Lebosol®-PK-Max the covering colour is promoted. At the same time, phosphorus contributes to better fruit firmness.
Some varieties are prone to nutritional leaf necrosis and premature leaf drop. The causes for this are, among others, an undersupply of manganese and magnesium. The combination of Lebosol®-Magnesium 400 SC with Lebosol®-Manganese 500 SC alleviates the symptoms and reduces premature leaf drop.
Molybdenum deficiency is known in citrus fruits as "yellow spot". Roundish to oval spots appearing glassy develop between the veins in spring, which later take on a golden yellow colour on the upper side of the leaf. In case of severe deficiency, the necroses can spread to the leaf margin, which rolls. Here, early and regular foliar fertilisation with Lebosol®-Molybdenum prevents the formation and development of the "yellow spot".
Boron in combination with calcium (Lebosol®-Robustus SC), zinc (Lebosol®-Zinc 700 SC) and amino acids (Aminosol®) have a positive influence on flowering, pollen tube growth and fruit set. They can be applied in this combination before flowering or after harvest to ensure optimal supply. The application of boron and zinc also promotes calcium absorption.