The influence of crop rotations on the fertility of leached chernozems of the Southern Urals

Abstract. The purpose of the research was to establish the degree of influence of crop rotations and mineral nutrition backgrounds on the fertility of leached chernozem. A comparative assessment of the main nutrition elements of humus, nitrogen of easily hydrolyzable, mobile phosphorus of plants in dynamics in the conditions of the northern forest-steppe of the Chelyabinsk region, in various crop rotations on two fertilization backgrounds P and NP was carried out. Methods. The research was carried out in a long-term field experiment on the land-use territory of the Chelyabinsk Research Institute from 1998 to 2021. Humus, total nitrogen and easily hydrolyzable nitrogen were determined in soil samples according to the method of I. V. Tyurin and M. M. Kononova in the modification of V. N. Kudeyarov, mobile phosphorus according to F. V. Chirikov. Results. According to the results of our research, it was found that, on average, over the years of observations 1998–2021, the humus content due to the crop rotation factor changed by 0.2 %, according to the fertilization backgrounds by 0.8 %. The nitrogen content of the total over the years of research increased in all crop rotation options from 20 to 55 %, regardless of the background fertilization. As a result of the conducted studies, it was found that the nitrogen content of the easily hydrolyzed significantly depends on the background of mineral nutrition and the conditions of the year, on average for 1998–2021, the decrease in nitrogen of the easily hydrolyzed was 17–22 %. On average, according to the variants of the experiment for 1998–2021, the process of assimilation of liquid phosphorus against the background of NP is more intensive by 8 %. A strong correlation was established between the productivity of crop rotations and total nitrogen against the background of P in 1998 and 2013, nitrogen easily hydrolyzed in 1998 and 2021, mobile phosphorus for all the years of research. The scientific novelty. Monitoring of the assessment of the state of soil fertility makes it possible to monitor, as well as diagnose the degree of anthropogenic impact, make appropriate adjustments to ensure high productivity of crop rotations in a changing climate.