Post harvest orchard fertilization is crucial — every orchardist has to remember that the end of the harvest does not mean the end of work in the orchard. On the contrary, this is the time for crucial actions that will prepare the fruit trees for winter dormancy and ensure they are in optimal condition to begin the next growing season. One of the most important tasks during this period is foliar fertilization with zinc and boron. Why?
Essential micronutrients in orchards – zinc and boron
After the fruit harvest is complete, fruit trees naturally enter a phase of preparation for winter dormancy. This period is crucial for the plants as they accumulate essential resources to survive the winter and ensure a strong start in the spring. In this context, post-harvest orchard fertilization, particularly with zinc and boron, plays a key role.
Zinc and boron are essential micronutrients for the proper development of plants, and their deficiencies can lead to significant health problems in fruit trees, ultimately reducing yield and quality. Foliar fertilization of orchards in the fall allows these nutrients to be stored in the plant’s shoots, from where they are drawn during the early spring for the intense growth and development of flower buds, leaves, and shoots.
Boron: a key micronutrient for post-harvest orchard fertilization
Boron is one of the most important micronutrients in fruit tree cultivation. Post-harvest fertilization of orchards with boron directly impacts the quality and size of the crop. Boron deficiency can lead to several issues, such as improper flower bud development, disrupted fruit setting, or fruit deformations.
Functions of boron in post-harvest orchard fertilization
Boron is essential for fruit trees, including apple, pear, cherry, and others. It stimulates cell division in apical meristem and, by enhancing cell division, positively impacts fruit size and its shelf life. Additionally, boron plays the following roles in fruit trees:
- Ensures proper growth and development of generative organs, such as pistils, anthers, and pollen.
- Stimulates flower fertilization, influencing fruit setting.
- Participates in cell divisions and apical meristem development.
- Involved in the synthesis and transport of sugars.
- Influences the structure of cell walls.
- Regulates water management and nutrient uptake by plants.
Symptoms and consequences of boron deficiency in orchards
Neglecting post-harvest boron fertilization in orchards can significantly reduce the quality and quantity of crops. Some of consequences include:
- Improper flower bud development, which can lead to flower dry-off.
- Disruptions in fruit setting, resulting in small cracked or corky fruits.
- In severe boron deficiency, vegetative organ issues such as delayed leaf bud breaking, leaf yellowing and deformation, stunted shoot growth, and even apical meristem die-back can occur.
- Tree bark may crack and become rough, and root growth may be stopped.
Symptoms of boron deficiency in apple fruits.
Zinc: crucial for orchards’ winter dormancy
Zinc also plays an important role in fruit tree cultivation. It is essential for the proper progression of many metabolic processes that influence crop yield, fruit quality, and overall plant health. Zinc enhances plant frost resistance and participates in chlorophyll and vitamin synthesis, as well as in growth and development processes. It also stimulates flower bud development.
Functions of zinc in post-harvest orchard fertilization
Zinc is an activator of many cellular enzymes and hormones. It participates in the synthesis of auxins, which are growth hormones, and in the metabolism of proteins and sugars. Zinc improves the efficiency of nitrogen fertilization and increases plant resistance to low temperatures and frosts, particularly to dangerous spring frosts for orchards. It also influences bud development and enhances resistance to certain diseases.
Symptoms and consequences of zinc deficiency in orchards
Zinc deficiency in fruit trees may result in thin, poorly leafed shoots with a rosette of small leaves at the tip. Other symptoms include shortened internodes, smaller leaves, often with chlorotic spots, and shoot tip die-back in severe and prolonged deficiency. Apples with zinc deficiencies are smal, and trees flower and fruit less effectively.
Apple witches’ broom deformation is a symptom of zinc deficiency.
Ensuring winter hardiness in fruit trees: the key to a successful season
Proper fertilization with zinc and boron directly affects the winter hardiness of fruit trees. Winter hardiness refers to a plant’s ability to survive low winter temperatures without frost damage. Most fruit tree species have relatively low resistance to temperature drops. Fall zinc fertilization positively affects bud frost resistance not only in fall/winter but also in spring. Proper post-harvest fertilization can also strengthen the cellular structures of trees, improve water management, and increase sugar content, which naturally protects against frost damage. Well-prepared fruit trees for winter better withstand frosts and start the new growing cycle in spring faster and healthier.
What zinc and boron fertiliser for orchards?
For fruit trees, a foliar fertiliser that is highly soluble in water and contains both of these important micronutrients in a form easily absorbed by plants is ideal. INTERMAG’s AMINO ULTRA® BORZIN is an excellent choice. This fertiliser is designed to simultaneously provide fruit trees in orchards with both zinc and boron. The last application of AMINO ULTRA® BORZIN can be applied at the beginning of leaf fall (5–10% fallen leaves) combined with a 5% urea solution (25–50 kg/ha urea in 500–1000 L of water). The purpose of this treatment is to accelerate the decomposition of fallen leaves, which in turn limits the development of fungal diseases.
Why to choose AMINO ULTRA BORZIN?
AMINO ULTRA® BORZIN is enriched with innovative GCAA technology. This technology involves combining micronutrients with glycine, the most mobile amino acid naturally occurring in plants. This ensures that micronutrients, in this case, zinc, nourish the plant more quickly and efficiently. This results in even greater efficiency and profitability due to the exceptionally low dosage per hectare. Another advantage is its biodegradability – the plant fully utilizes the glycine-micronutrient complex.
