After harvesting in orchards, it is time to apply nutrients for the next vegetation year. The exception are olives that are still bearing fruit, are undergoing intensive oil accumulation and are mostly fed from summer to harvest, by entering into the soil and by foliar application.
In the basic fertilization of fruit trees and olives, we distinguish the fertilization of young plants and fruit-bearing plants. From the production point of view, the most important period is the period of full fertility when fertilization is a very important agrotechnical measure. To ensure good nutrition, nitrogen, phosphorus, potassium, and, if necessary, boron, zinc, magnesium and other nutrients are added to the soil. Determination of quanty of plant nutrients in regular fertilization is done by chemical analysis of the soil, which determines the supply of accessible nutrients in the soil, as well as by the analysis of leaves (foliar analysis) at a certain stage of vegetation. In basic fertilization of perennial crops, fertilizer with less nitrogen and more phosphorus and potassium is used. Its application is linked to autumn soil treatment and is primarily used for the introduction of phosphorus and potassium into deeper layers of soil. In olive groves, it is carried out earlier, from September to November, in order for a portion of the feed to be used for completing of the ripening process and oil production in the fruits. On skeletal and karst soils where the treatment is impossible, mineral fertilizer is scattered before rain. A portion of nitrogen is also added, which serves for feeding roots during winter and its build-up in the tissue of the wood.
Fertilization of young fruit and olive trees
In the first and second year, the trees are fertilized individually. The fertilizing area around the fruit and olive trees should be somewhat wider than the crown. In the first year of cultivation, in the basic fertilization of fruit and olive trees of a thick cluster, each tree is fertilized with 0.25 kg NPK 7-20-30. For the orchard of a thin cluster, one fruit is given 100 - 150 grams. In the second year, fertilization is carried out at the same time with the same type of fertilizer, with the amount increasing by 50%. In the third and the other years of cultivation, fertilization is carried out on the whole area of orchard and olive grove.
Fertilization of fruit-bearing fruit and olive trees
Fertilization of fruit-bearing fruit and olive trees ensures regular and high yields, good fruit quality, and the balance of the development of vegetative and generative organs. In basic fertilization that is carried out in the autumn after harvest, complex NPK fertilizers are introduced, with a little nitrogen, more phosphorus and the most potassium. The fertilizers are applied throughout the plantation surface. Exceptionally, in the plants of a thin cluster or in the case of individual trees, they are added to the area around the trees, somewhat wider than the crown. Basic fertilization of orchards and olive groves is done with 400-500 kg / ha (40-50 kg / 1000 m2 or 40-50 g / m2) of NPK 7-20-30, or 570-700 kg / ha (57-70 kg / 1000 m2 or 57-70 g / m2) NPK (MgO, SO3) 7-14- 21 (2.18). In olive groves, in September and early October, nitric sulfur fertilizers such as PETROKEMIJas (NS 20-24) or ASN (NS 26-15) are added for more intensive oil accumulation in olive fruits in the amount of 100-150 kg / ha (10-15 kg / 1000 m2 or 10-15 g / m2). In skeletal soils one should take into account the percentage of skeleton. If skeleton percent exceeds 50% of soil volume, the total amount of fertilizer is applied in at least two servings.
Fertilization when planting fruit and olive trees in small planting pits
When planting seedlings in small planting pits of 40 cm x 60 cm x40 cm profile, 20-30 grams of high-concentration NPK mineral fertilizer is applied, such as NPK 7-20-30 or 30-50 grams of NPK (MgO, SO3) 7-14-21 (2 , 18). These fertilizers are mixed with the total soil mass. For larger planting pits than 1 m3, the same fertilizers are introduced, but in an amount of 0.5 to 1 kg per 1 m3.
Properly applied autumn fertilization of perennial crops ensures a safe and high yield of subsequent vegetation, and the return of the nutrients into the soil.