Fruit crops, by their nature, are quite demanding in mineral nutrition conditions. The weather in spring 2019 was generally favorable for fruit crops, with no frosts during flowering, but after last year's record yield it is visibly noticeable on some apple varieties that the number of fruit set is considerably lower. Given this, to reach the planned yield, more attention must be paid to mineral nutrition throughout the whole period of yield formation.
Prolonged rains in many regions in late April and almost two ten-day periods of May certainly had a positive effect on building soil moisture reserves, but increased humidity also means an increased risk of plant disease spread. Comfortable mineral nutrition conditions mean the plant itself can resist diseases to a considerable extent. Nutrients that raise plant resistance to disease agents include: phosphorus, calcium, magnesium, boron, copper, zinc. Each of these elements «works» in its own segment. In particular, phosphorus ensures energy metabolism in the plant and powerful root system growth, and the phosphite form of phosphorus stimulates the synthesis of protective substances, phytoalexins, in the plant. For this property special fertilizers based on phosphites are registered as fungicides that suppress pathogens of various groups.
Calcium, which strengthens cell walls, to some extent reduces the chance of the pathogen penetrating into the cell and regulates the acid-base balance, which is also a certain barrier to disease agents.
Magnesium, as a component element of chlorophyll, promotes stronger photosynthesis and better uptake of other nutrients.
One of the main functions of boron in the plant is the formation of healthy vascular bundles.
Copper and zinc are part of enzymes that form plant resistance to disease. People noticed this property of theirs long ago and used it to protect plants. It is worth recalling that the first fungicide, Bordeaux mixture, is nothing other than copper sulfate in an alkaline medium.
Considering the above, the system of foliar feedings in the first half of the growing season of fruit crops must take into account plant needs, first of all, for exactly these nutrients. On this basis and considering positive experience of use, we recommend foliar feeding of orchards after flowering with the tank mix Ecoline Phosphite (K) 1.5 l/ha + Ecoline Boron (Premium) 1.0 l/ha. The second foliar feeding of plants is advisable at the start of the fruit formation stage with the composition Ecoline Magnesium (Chelates) 2.0 l/ha + Ecoline Zinc (Chelate) 0.5–1.0 l/ha. The third feeding should be done when pome fruits reach «walnut» size. In this period it is important to supply plants with elements responsible for forming the quality indicators of the crop. For foliar feeding in this period we suggest the tank mix Ecoline Calcium–Boron (Chelate) 2.0–2.5 l/ha + Ecoline Phosphite (K–Zn) 1.5 l/ha.
If leaf diagnostics is carried out and a need for other mineral nutrients is established, we can select the needed compositions for specific conditions from the range of registered ECOORGANIC fertilizers. In addition, for orchards with drip irrigation systems we can offer feeding with liquid NPK complexes from the new Fitostart line.