Morphological characteristics, humus and nutrient content of recent and buried soils of the Inozemtsevo mound

Abstract

The main objective of the work was to identify the evolutionary changes in the profile of recent and buried soil in the Holocene, the content of humus and the composition of mobile forms of nutrients in the solonetzol- silted black soil in the insufficiently wetted zone of Stavropol Krai. The research was carried out near the village of Inozemtsevo, Stavropol Krai. The soils of the study area are formed on marine sediments. A 1.5-metre-high grave was erected more than 5,000 years ago. At a distance of 150 metres, an incision was made on recent virgin soils. According to morphological characteristics, recent soils are medium saline fused medium powered black soils, while the buried soils evolved into weakly saline fused low powered black soils. They are distinguished by lower profile thickness and brown, rather than black, colouring. There is a BC horizon in recent soils, which is absent in paleosoils. New formation of carbonates and gypsum is noted only in recent soils in B2 and BC horizons. The organic matter content in recent soils is 5-6% and decreases 6-7 times in paleosoils in the upper horizons. Recent soils are depleted in mobile phosphorus, but enriched in mobile potassium. Differences in the content of mobile sulphur are due to some salinity of the paleosoils. In the content of mobile trace elements, the differences between the studied soils are significant, especially zinc, cobalt and molybdenum. Consequently, during the evolutionary period of 5 thousand years, the soil-absorbing complex was impoverished by these microelements.