Role of humic acids-based fertilisers and nitrogen fertilisers in the regulation of the macroelement content in maize biomass

Mineral fertilisers are applied to soil to replenish or maintain at the necessary level its abundance of available nutrients, and to optimise the genetic production potential of plants. Humic substances are biologically active compounds of organic matter in the soil that effectively support mineral fertilisers in the cultivation of various crops. The aim of this study was to determine the effect of increasing doses of humic acids-based fertilisers (HAs) on the regulation of the macroelement content in maize grown on two soils (loamy sand and sand) fertilised with different nitrogen fertilisers (ammonium nitrate - AN, urea - U and urea and ammonium nitrate solution - UAN). Nitrogen fertilisation had a greater effect on the macroelement content of plants on sand. The highest macroelement content in maize grown on this soil was found on soils fertilised with UAN. Urea induced similar but smaller changes in the K, P and Na content of maize, but not in Mg and Ca. Urea also had the most favourable effect on plant biomass. HAs tended to increase the macroelement content of plants. On the sand, HAs had the greatest effect on the UAN fertilised objects, causing an increase in Mg, P, Ca and K compared to the unfertilised object. On loamy sand, the changes in their content in maize were less clear. HAs can be a good source of essential elements for plants by supporting the effectiveness of mineral fertilisation.