Corn made the most significant contribution to Ukraine's record 2018 grain harvest. According to the Ministry of Agrarian Policy of Ukraine, as of 29 November, Ukrainian farmers had threshed 68.5 million tonnes of grain from 14.5 million ha (98%) at a yield of 47.2 c/ha. Of this, corn accounted for 33.3 million tonnes from 4.3 million ha (95%) at a yield of 76.9 c/ha .
Such significant results were achieved thanks to high-yielding hybrids and adapted growing technologies, in which optimizing mineral nutrition conditions has an important place.
Corn is a crop demanding in mineral nutrition. This is due, first of all, to its long growing season and the plant's ability to take up nutrients until the very end of grain ripening.
To form 1 t of grain and the corresponding mass of by-products, corn hybrids of different maturity take up from the soil and fertilizers on average:
24–30 kg of nitrogen, 10–12 kg of phosphorus, 25–30 kg of potassium,
6–10 kg of magnesium and calcium, 3–4 kg of sulfur, 11 g of boron,
14 g of copper, 110 g of manganese, 0.9 g of molybdenum,
85 g of zinc, 200 g of iron.
The root system of corn plants has a high ability to take up nutrients from the soil and effectively uses residual nutrients from fertilizers applied to the preceding crop. Corn is traditionally considered an «indicator» of microelement content in the soil. Corn is especially sensitive to shortage of zinc (Zn), manganese (Mn), copper (Cu) and boron (B), which affects plant development and reduces crop productivity.
Zinc takes part in the synthesis of chlorophyll and vitamins, affects growth and development, and raises resistance to unfavorable conditions, in particular frosts. Zinc plays an important role in the biosynthesis of growth hormones of auxin nature. With significant zinc shortage, ears may fail to set on plants. A sign of zinc shortage is interveinal chlorosis, which first appears on younger leaves.
Boron positively affects the formation of healthy vascular bundles of stem and root, fertilization and grain formation processes, carbohydrate metabolism and respiration. Boron shortage inhibits plant growth.
Copper promotes better nitrogen uptake, increases protein and sugar content in grain, raises yield and resistance to disease. Copper shortage can appear with high rates of nitrogen and phosphorus, in dry and warm weather.
Realizing the productivity potential of corn depends substantially on soil and climate conditions, yet no less important in modern growing technologies is a balanced plant nutrition system that includes pre-sowing seed treatment with microelements, basic fertilization before sowing and foliar feeding.
Pre-sowing seed treatment
The aim of pre-sowing seed treatment is to create comfortable conditions for the young plant in the period from germination to switching to feeding from its own root system, which ensures a fast, powerful start of plants.
Pre-sowing seed treatment with fertilizers not only raises yield and the quality of the product obtained but also ensures plant resistance to a complex of diseases and unfavorable environmental conditions (low or high temperatures), speeds up plant growth and development and promotes more productive use of moisture. Pre-sowing seed treatment with microelements often gives a better effect than applying fertilizers into the soil for corn, even at higher rates.
Foliar feeding
In modern growing technologies, foliar feeding with complex fertilizers with microelements in chelate form, and with other active substances, in particular amino acids and phytohormones, is quite an effective technique. The main aim is to improve plant nutrition and support plants in the most critical periods of growth and development, reduce the negative effect of environmental conditions (weather, chemical treatments), strengthen the intensity of formation of individual plant organs, influence the outflow of nutrients and raise product quality.
In the development of corn plants, the three-to-five and six-to-eight leaf stages are considered the most critical for their supply of macro- and microelements.
The three-to-five true leaf stage is important in that at this time the generative organs that determine future yield are forming in corn. The number of ears per plant and kernels on them depends on the supply of nutrients to corn, especially phosphorus. The young corn plant grows weakly, its root system is not yet sufficiently developed and cannot take up nutrients from hard-to-access compounds, so to stimulate root growth it is important to supply corn plants, besides phosphorus compounds, with manganese (Mn), zinc (Zn) and boron (B).
At the six-to-eight leaf stage fast growth of vegetative mass begins and, accordingly, nutrient requirements rise. Corn plants very often come under herbicide stress, so for feeding in this period it is desirable to use compositions containing phosphites, amino acids and phytohormones.
Given that in most cases soil reserves of available microelements are not enough to supply the plant in the needed amounts, or for various reasons are hard for plant root systems to access, additional application in the critical periods of growth and development is needed. The most effective way of applying microelements is foliar feeding with microfertilizers in chelate form.
In the 2018 season ECOORGANIC, in cooperation with other companies, carried out a number of field trials with different hybrids and corn foliar feeding systems developed with the features of the region where the trials were held in mind.
In Ternopil region, at the demo plot of Pioneer Nasinnia Ukrainy LLC at Mshanetske farm in Mshanets village, Terebovlia district, hybrid P8567 (FAO 290) (Pioneer) was grown.
The soil was typical chernozem, the preceding crop winter wheat. Basic fertilization for the crop was N130P78K78 in active substance.
The foliar feeding scheme is given in table 1.
Foliar feeding of corn plants in the early development stages showed excellent results in all variants .
The results obtained indicate high effectiveness of foliar feeding with the fertilizer Ecoline Zinc Chelate. A gain was recorded in all trial variants. The highest corn grain yield gain compared with the control without foliar feeding was obtained in the variant with Ecoline Zinc Chelate at 2.0 l/ha + Gros Rootgrowth 1.0 l/ha. It amounted to 7.7 c/ha in clean weight.
Economic efficiency calculations showed that fertilizer costs in this variant were USD 27.5, while the yield gain obtained at purchase prices at the end of November was worth USD 140.1. Thus the conditional net profit in this variant was USD 112.6.
At the demo plot of VK Tekhnopol in Kirovohrad region the hybrid ES Metod was grown. The soil of the trial plot was typical chernozem. The preceding crop was corn. Basic fertilization in active substance was: N142P38K28S6.
Foliar feeding was carried out in the key plant development stages
During the growing season plants were sampled and the results of interim assessments recorded
Yield assessment at combine harvest showed that a yield gain from foliar feeding occurred in all variants. The highest was at the 3–5 leaf stage: Ecoline Zinc Chelate 1.0 l/ha + Ecoline Phosphite K 1.0 l/ha + Ecoline Universal Growth Amino 1.0 l/ha, and at the 6–9 leaf stage: Ecoline Corn Chelates 1.0 l/ha + Gros Phosphito-NP 1.0 l/ha + Ecoline Boron Premium 1.0 l/ha.
Financial efficiency calculations showed that there is not always a direct correlation between the size of the yield gain and profit in monetary terms. It also depends on the cost of fertilizers.
