Spatial heterogeneity of the content and reserves of humus of virgin light gray forest soils of the south of the Tyumen region

Abstract

The results of the analysis of the state of humus in virgin light gray forest soils in the south of the Tyumen region are presented. A total of 96 full profile sections were made and described, soil samples were taken for laboratory studies. The results were processed in MS Excel using the Descriptive Statistics tool. It was revealed that the subtype of light gray forest soils has a low content of humus in the upper part of the profile - 2.07±0.47 %. A sharp decrease in the humus content down the profile was established. In the A₁A₂ horizon, the average humus content in the sample is 1.09 % with fluctuations from 0.61 to 1.65 %. Humus formation in the studied soils is of an accumulative nature, since soils with an above-average humus content predominate in the analyzed sample. The content of total nitrogen in horizon A₁ is 0.11±0.03 % at a carbon to nitrogen ratio of 11.2±1.0. Down the profile, the content of total nitrogen sharply decreases, which is associated with the leaching of water-soluble nitrogen compounds. On average, humus reserves in the A₁ horizon are 38±11.7 t/ha, which is half of the reserves in the 0-100 cm layer. When light gray forest soils are involved in arable land, the nutrient regime of agricultural crops will be formed exclusively due to the A₁ horizon.