Ефективні агрономічні практики оптимізації вмісту та якості гумусу в ґрунті

The results of the study of quantitative and qualitative changes in organic matter (humus) of typical chernozem (HaplicChernozem) irrigated with suitable water under different fertilization systems in vegetable-forage crop rotation within theframework of a field experiment are presented. The content of soil organic carbon is one of the main descriptors of soilhealth, and plays an important role in ensuring food security, achieving climate neutrality and preventing biodiversity loss.During the conducting the stationary experiment (1967–2024) on the non-fertilized irrigated variant a decrease of thehumus content in the arable and subsoil layers of the soil compared to the non-irrigated control with a traditional fertilizationsystem was established. The different fertilization systems — sideral, mineral, organic, organo-mineral and biologicalunder irrigation contributed to the improvement of the carbon balance and the increase of humus content in the arableand subsoil layers of the soil compared to the control without fertilizers. Thus, in the soil of the 0–30 cm layer the increaseof humus content in different variants was 6.0–14.7 %, and in the 30–50 cm layer it was 4.4–22.6 %. The application ofagronomic practice of optimizing the content of humus through fertilization also affected changes in the quality of organicmatter (humus). According to the results of the spectroscopic analysis, the absorption spectra of humic substances of thesoil in the different variants of the experiment are represented by a typical sloping line. This indicates the similarity of thestructural organization of humic substances. The main changes are observed in the UV range. This is due to aromaticstructures and polyphenolic functional groups. The highest content of aromatic structures in preparations of humicsubstances was found in variants with organo-mineral and mineral fertilization systems and in non-irrigated soil.