Balanced mineral nutrition combined with integrated plant protection can ensure fuller use of the genetic potential of hybrids and so give a higher yield of good quality. The period from the formation of 6–8 leaf pairs is extremely important in sunflower ontogeny. At this time the main yield element of the crop, the head, is in full formation, and a shortage of key mineral nutrients and stresses of various kinds adversely affect the future yield.
The weather this spring and in the first days of June is marked by many anomalies: part of the areas in the south suffered from drought, while across the country many crops were flooded and damaged by hail. In such conditions it is not always possible to carry out the planned crop care operations on time, so we have selected recommendations that can be applied flexibly from the 6–8 leaf pair stage of sunflower to the «star» formation stage.
ECOORGANIC is a producer of a wide range of foliar nutrition fertilizers, whose effectiveness many farmers have verified. Among the company's products, compositions containing L-α-amino acids, with which plants overcome stress faster and form a higher yield, have become especially popular.
Sunflower is a boron-loving crop. A shortage of boron during growth of vegetative mass and formation of vascular bundles and flowers adversely affects yield. Since boron is hardly mobile in the plant, it is desirable to apply the needed dose in parts, in two or three passes.
For the 6–8 leaf pair stage the composition Ecoline Boron (Premium) is the best fit. Besides 140 g/l of organic boron, this product contains 10 g/l of L-α-amino acids, which help sunflower plants overcome stress quickly. The rate for one application is 0.5–1.0 l/ha.
An important role in the mineral nutrition of the crop belongs to phosphorus and potassium, which promote the formation of healthy plants. On soils with low content and low availability of zinc, feeding with fertilizers containing this element is quite effective for root system development. The composition Gros Amino-Zn with 80 g/l of zinc and 60 g/l of L-α-amino acids is well suited for this. The recommended dose of this fertilizer for feeding sunflower at the 6–8 leaf pair to «star» stage is 1.0 l/ha. The fertilizer can be applied separately or with the addition of Ecoline Phosphite (K) 1.0 l/ha.
As functional diagnostics results show, plants need additional feeding with macro- and microelements that are hard to access under insufficient or excessive moisture supply. Stress factors have a significant influence on the active development of young sunflower plants. Moisture shortage and temporary waterlogging on the one hand, and the phytotoxic effect of soil and rescue herbicides on the other, can cause significant losses in both yield and seed quality. Even on crops of hybrids resistant to one or another group of herbicides, signs of stress are often observed in the first days after their application. Every such stress reduces the potential yield by 5–15%! To help plants overcome this state, the optimal measure in this period is the use of special foliar nutrition fertilizers, anti-stress products containing free L-α-amino acids. On such crops we suggest using the microfertilizer Ecoline Phosphite (K-Amino) at 1.5–2.0 l/ha, which contains 70 g/l of L-α-amino acids that plants quickly absorb and that bring them out of stress.