Composition of Water Extracts from Plant Material and Soils on Calcareous Rocks and of Surface Water in the Northern Part of the Polar Urals

摘要

A comparative analysis of the chemical composition and properties of water-soluble compounds of the soils on calcareous rocks, aboveground phytomass, and waters is performed for the northern part of the Bolshoi Paipudynsky Ridge (Polar Urals, Russia). Potassium and calcium ions (45-60 and 30-45, respectively) are prevalent in the water extracts of plant material. From the O horizon to mineral horizons, the content of Ca2+ ions in water extracts increases from 50-70 to 80-90 with a concurrent decrease in the content of K+ ions from 12-34 (O horizon) to zero (mineral horizons). Uniform compositions of surface waters and water extracts of lower soil horizons reflect the specific features inherited from the soils of the catchment area. The properties of the group of humus horizons-gray-humus (AY), mucky-dark-humus (AH), and mucky (H)-are most variable. The water extracts of the phytomass contain 8-106 g/kg C-org, 0.4-5.8 g/kg N-org, and 1.5-32 g/kg soluble salts. The contents of all these components in water extracts by the O horizon decreases by 1-1.5 orders of magnitude and further by 1-2 orders of magnitude in the mineral horizons. The surface waters are ultrafresh. In the absence of organic compounds, their acid-base properties are mainly controlled by carbonates and bicarbonates of alkaline and alkaline- earth metals.