Change in the humus state of typical chernozem with various methods of tillage

Relevance. The article is devoted to the influence of various methods of tillage on the humus state of typical chernozem (Haplic Chernozems).Methods. Tillage options: plowing with a formation turnover (20–22 cm); combined processing (disking 8–10 cm + chisel 20–22 cm); surface treatment (disking) up to 8 cm; direct sowing. The object of the study was a typical powerful heavy loamy chernozem.Results. According to the results of the group and fractional composition of typical chernozem humus (regardless of the method of processing and the studied soil layer), the following patterns were established: the predominance of a group of humic acids (HA — 45–55% of organic carbon (Sorg.), a high proportion of humic acids associated with calcium (HA-2 — 29–41% of Sorg.), low content of non-hydrolyzable residue (NO — 29–36% of Sorg.), humate type of humus (Sgc:Sfk > 2), a very high degree of humification of organic matter (>4.5). With an increase in the depth of the arable layer (regardless of the method of tillage), there is an increase in Sgc, Sgc-2 and a decrease in carbon of humic acids free and associated with mobile oneand-a-half R2O3 (Sgc-1), carbon of humic acids associated with stable R2O3 (Sgc-3), and carbon of fulvic acids (Sfk). In the 0-20 cm layer, the predominance of Sgc-1 (5.5%) is noted, and their content decreases depending on the method of tillage in the series “combined (5.08%) → surface treatment → direct sowing (4.91)”. When applying an extreme degree of minimization (direct sowing) in a layer of 0–20 cm in relation to other methods of tillage, the largest amount of Sgk-2 is noted. The content of Sgk-3 and Sfk was highest with surface and combined treatment.