CHANGES IN AGRO-CHERNOZEM HUMUS STATE UNDER FERTILIZERS INFLUENCE

The aim of the study is to assess the humus status of the agrochernozem of the Krasnoyarsk forest-steppe under the conditions of using mineral and humic fertilizers. The study were conducted in 2023–2024 at the Minderlinskoye educational farm of the Krasnoyarsk State Agrarian University, located in the Krasnoyarsk forest-steppe (56°43' N, 92°91' E). The objects of the study are typical clay-illuvial agrochernozem, agrocenosis of spring wheat of the Novosibirskaya 31 variety, humic fertilizers Lignohumate AM and Gumat Potassium Souffleur, and mineral fertilizer ammonium nitrate. The functioning of highly humus agrochernozem in spring wheat crops was accompanied by insignificant and small dynamics of Chumus (Cv = 3–10 %) and a wider seasonal range of its mobile compounds (Cv = 6–30 %). The nature of the dynamics of humic substances is determined by the weather conditions of the growing seasons and the fertilizers used in the experiment. Evaluation of the average statistical content of humic substances showed that the humic fertilizer Lignohumate AM in combination with ammonium nitrate at a dose of N30 and N60 has the maximum effect on the content and reserves of carbon in humic substances. In these experimental variants, the increase in humus carbon compared to the control variant is estimated at 9–14 %; water-soluble carbon – 13–21; alkali-hydrolyzable carbon – 34–35 %. The use of Humate Potassium Souffleur is most effective when treating seeds and spraying crops on an unfertilized background and increases the content of Chumus by 11 %, mobile carbon compounds – by 15–29 %. The use of humic fertilizers in the technology of spring wheat cultivation after a fallow predecessor allows fixing in the composition of soil organic matter from 7 to 20 t C/ha in the 0–40 cm layer of agrochernozem and improving the quality of humus by increasing the proportion of humic acid carbon in the composition of its mobile compounds.