Mineral fertilizers influence on the potassium uptake dynamics by corn cultivated in the Trans-Urals forest-steppe zone

Corn is a crop that takes out a large amount of nutrients. Especially strong removal is noted for potassium, since a significant part of it is contained in the vegetative mass of plants, and the biomass of corn is several times higher than other agricultural crops. Many commodity producers refuse to apply potash fertilizers, limiting themselves only to the use of nitrogen and, in rare cases, phosphorus fertilizers, focusing on the high content of potassium in soils. However, a high agrogenic load on lands involved in permanent agricultural use leads to a stable decrease in this element in soils, which in the near future will lead to its deficiency and imbalance of nutrients. Therefore, to understand the whole problem, additional study of potassium nutrition is necessary. The study was conducted in the forest-steppe zone of the Trans-Urals in the Zavodukovsky District of the Tyumen Region in 2016–2018, on leached chernozem. The scheme of the experiment provided for an option without the use of mineral fertilizers and with the introduction of NPK on the planned yields of 4.0 to 6.0 t/ha of corn grain. In the experiment, a hybrid Obsky 140 was sown, the seeding rate of which was 70 thousand plants per hectare. It was found that the potassium content in corn decreases during plant growth. By flowering, corn absorbs up to 50 % of the required amount of potassium. The maximum consumption of potassium falls on the period of grain maturation – 43–52 % of the total removal for the entire growing season. The introduction of mineral fertilizers contributes to an increase in the economic removal by 32–62 % relative to the control.