Influence of an anthropogenic factor on changes in the content and composition of humus in chernozems of the lake Sevan basin of the republic of Armenia

Abstract

The article analyzes the results of research on the impact of anthropogenic factors on the changes in the content and composition of humus in chernozems . The studies showed that the amount of humus in arable soils consistently decreases. It was found that its content in the “A” horizon of virgin soil averages from 6.1 to 9.9%. It was determined that with prolonged plowing, the humus content in the arable layer decreased to 5.6% (to an average level). In a consistent pattern, there is also a decrease in the content of total carbon and nitrogen in arable variants. Research shows that as the humus content decreases, the amount of humic acids (HA) also decreases. It was found that with the depth of the profile, the relative content of HA (% of total C) decreases, while fulvic acids (FA) increase, and the type of humus transitions from fulvate-humate in the “A” and “B” horizons to humate-fulvate in the “BC” and “C” horizons. It was established that prolonged and unsystematic agricultural use of chernozems led to a decrease in humus content and a change in the qualitative composition of humus. Throughout the profile, these changes are expressed in a decrease in the total amount of humic acids, fulvic acids, and non-hydrolyzable residue.