Influence of polymer modification of complex fertilizer on the efficiency of phosphorus and potassium use by winter wheat on the southern chernozem

In modern conditions of unprecedented challenges, an alternative to the technological degradation of fertilizer application systems can be the development of original forms of long-acting fertilizers. Despite significant progress in the adaptation of progressive systems of agrochemical impacts, the use of traditional forms of mineral fertilizers does not allow using the full potential of the introduced nutrients, since the processes of incomplete denitrification, immobilization and leaching (leaching) of the main macronutrients (NPK), along with the action of urease, lead to unproductive loss of nutrients in the soil. In addition to economic losses, there are negative environmental consequences – eutrophication of water bodies, emission of greenhouse gases. The studies were carried out in 2022 under production conditions in the Kursk district of the Stavropol Territory on the farm of “StavAgroCom” on southern carbonate chernozem. As a modifier of mineral fertilizers, one of the most common synthetic polymers, polyvinyl alcohol (PVA), was used. The polymer consumption rate was 3, 5 and 7 kg per 1 ton of fertilizer. Yield growth was positively correlated with the dose of polymer in the fertilizer. The analysis of soil properties was carried out by the method of principal components. The resulting clustering in the coordinates of the first two components (in total they explain 65% of the data variation) shows significant differences in soil properties under different experimental options. To assess the efficiency of the use of nutrients depending on the dose of the polymer, a differential indicator was proposed – the additional efficiency of the use of nutrients (E). It was estimated from the increase in yield relative to the zero dose of the polymer per unit reduction in the concentration of this element in the soil according to the proposed formula. It is shown that the polymer use in fertilizer gives a statistically significant increase in the efficiency of phosphorus and potassium use by winter wheat.