On different soil types plants may lack certain mineral nutrients. Particular attention should be paid to supplying sunflower with boron. 5.0 mg of boron per 1 kg of soil is the limit below which the first symptoms of shortage of this element begin to appear, and with a content of less than 3.0 mg / 1 kg such symptoms can be very noticeable.
Boron plays an important role from seed germination onward and throughout the growing season. It takes part in regulating carbohydrate metabolism and in the synthesis of amino acids, proteins and chlorophyll. Boron is also important for sunflower root system development. It improves the outflow of carbohydrates to this part of the plant and activates its growth.
To supply sunflower plants with boron at the 3–5 leaf pair stage we recommend using ECOLINE Boron (Premium) at 1.0 l/ha. Applying boron together with L-α-amino acids promotes better boron uptake and softens the negative effect of stress factors of various kinds.
On soils with a low fertility level and a high spread of disease agents in the soil, feeding is advisable with the tank mix ECOLINE Boron (Premium) 1.0 l/ha + GROS Phosphito-NP 1.0–1.5 l/ha to strengthen vegetative plant growth and hold back disease development.
On carbonate soils of heavy texture and with moisture shortage, sunflower plants may show signs of zinc deficiency. In this case, instead of GROS Phosphito-NP it is advisable to use ECOLINE Phosphite (K-Zn) at the same dose of 1.0–1.5 l/ha.
If deficiency of other nutrients (manganese, iron, molybdenum, etc.) appears, established visually or from laboratory analysis, the corresponding chelate fertilizers from ECOORGANIC can be used for foliar feeding of sunflower plants.
Sunflower plants 2 weeks after the first foliar feeding (at the 3–5 leaf pair stage). K – control (farm scheme), 1 – ECOLINE Boron (Premium) 1.0 l/ha, 2 – ECOLINE Boron (Premium) 1.0 l/ha + GROS Phosphito-NP 1.5 l/ha. (Romaniv farm (trial field of Pioneer Nasinnia Ukraina LLC), Volyn region, 2019)