Fertilizer application rates and recommendation for sunflower

During the growing season, the sunflower absorbs nutrients unevenly. So, during the first month of vegetation, it uses 15% of nitrogen, 10% of phosphorus and 10% of potassium, although the accumulation of organic matter during this time does not exceed 5% of the maximum value. Despite the fact that the sunflower grows slowly at the initial stage (2-3 pairs of leaves), a basket is laid during this period. In the next 1.5 months, when the basket is formed, and until the end of flowering, this culture intensively consumes nutrients, assimilates 80% of nitrogen, 70% of phosphorus and 50% of potassium. The last amount of potassium (40%) is absorbed from the phase of filling of ovules to the beginning of maturity. After the formation of baskets is completed, the assimilation of nutrients decreases.

During the sunflower growing season, there are several critical periods of assimilation of nutrients. In the initial stages, before the formation of baskets, sunflower develops quite slowly and does not require a large amount of nutrients. Excessive nitrogen nutrition at the initial stage of development leads to a decrease in yield. The need for nitrogen nutrition increases during the phase of basket formation. This period is also the most important in providing sunflower plants with trace elements, especially boron, because its lack sharply reduces yield.

Balanced nutrition of sunflower with trace elements is extremely important for increasing grain production.

According to the Institute of Agriculture of the Steppe Zone of the National Academy of Sciences , sunflower is demanding of trace elements, as evidenced by their significant accumulation in plants. Zinc accumulates the most in the seeds and manganese in the vegetative part.

The critical periods for feeding sunflower with trace elements are the phases of 2-3 pairs of leaves and budding (8-10 pairs of leaves ). Lack of boron, zinc, and manganese in the first period leads to insufficient harvest. Molybdenum, copper and iron are also important for sunflower.

Wonder Leaf Mono B 11 (B-11%), or Wonder Leaf Mono B 120 (B-9%) or Wonder Leaf Pink (B-20%) significantly affects carbohydrate and protein metabolism and other biochemical processes in plants. Due to its lack, the transition of carbohydrates and starch from leaves to other organs is disrupted, as a result of which the process of photosynthesis is inhibited, the root system is not sufficiently supplied with carbohydrates, which impairs its development. Boron plays an important role in the development of reproductive organs. It almost does not move from the lower part of the plant to the point of growth, that is, it cannot be reused. This trace element increases drought resistance and salt resistance of plants. Boron deficiency is aggravated by excessive application of potash fertilizers and lime. Boron deficiency is accompanied by disturbance of carbohydrate and protein metabolism. The main need of sunflower for boron (80% of the total amount) is observed in the phase of 5 pairs of leaves.

Wonder Leaf Mono Mn 11 (Mn-11% chelate) is important because it participates in redox reactions in plant cells and is associated with the activity of oxidizing enzymes – oxidase. In case of lack of this element, the intensity of oxidation-reduction processes and synthesis of organic substances in plants decreases.

Manganese helps substances move through plant organs. It plays an important role in the processes of assimilation of ammonium and nitrate nitrogen by plants. With ammonium feeding, it acts as a strong oxidizing agent, and with nitrate feeding – as a strong reducing agent. Therefore, in the case of manganese deficiency, the recovery of nitrate nitrogen is disturbed, which leads to the accumulation of nitrates in plant tissues.

Manganese participates not only in the process of photosynthesis, but also in the synthesis of vitamin C. In case of manganese deficiency, the synthesis of organic substances decreases, the chlorophyll content  in plants decreases which leads to chlorosis. Low air humidity, low soil temperature and gloomy weather prevent the assimilation of manganese. A lack of manganese is observed on soils with a neutral or alkaline reaction, and its availability is high on acidic soils.

Wonder Leaf Mono Zn 8 (Zn-8% chelate) affects the total content of carbohydrates, starch and protein substances. It plays a major role in redox reactions of respiration, regulation of ATP synthesis , exchange of auxins and RNA .

Zinc has a positive effect on the heat resistance of plants and the formation of grains in dry conditions, that is, it contributes to the accumulation of organic acids in flowers which act as protective substances. In addition, this element increases the cold resistance of plants.

With a lack of zinc, protein synthesis is disrupted and its content in plants decreases. This is explained by the fact that due to its lack, amides and amino acids, that is, soluble nitrogen compounds, accumulate in plants. High levels of phosphorus and lime, low soil temperature prevent the assimilation of zinc.

Wonder Leaf Mono Fe 10 (Fe-8.8% chelate) takes an active part in metabolic processes, is part of enzymes involved in redox reactions: peroxidases, catalases, cytochrome oxidases, NAD-H-cytochrome-C reductase, activates respiration, affects the formation of chlorophyll. Lack of iron leads to a decrease in the intensity of photosynthesis, chlorosis appears on young plants. High soil moisture prevents the assimilation of the element.