MICROBIAL TRANSFORMATION OF NITROGEN AND CARBON COMPOUNDS IN ALPINE MOUNTAIN-MEADOW SOIL OF THE MALAYA KHATIPARA RIDGE

摘要

A large body of data has been accumulated on the nitrogen and carbon cycles in tundra, forest, steppe, and desert ecosystems. Features of cycles of these elements in mountain-meadow cenoses have been studied significantly less thoroughly [1]. The diversity of soil cover in the alpine meadow zone is related to strong differences in ecological factors dictated by the local mesorelief. Combination of ridges, slopes of varying steepness and exposure, sinks on slopes, and leveled areas at their bottoms primarily determines the nonuniform distribution of atmospheric precipitation among these relief elements and the intense geochemical migration of weathering and pedogenesis products. Of special significance is the different accumulation rate of snow cover, which not only controls water supply conditions, but also determines differences in duration of the growing season. These differences are most pronounced in the alpine zone, where snow cover can be completely absent on windward slopes and its depth atslope bottoms attains 5 m and more. In snow-free and low-snow habitats, the vegetation of plants begins already in May. In the places of the highest accumulation, snow cover disappears only in June, and the growing season is no longer than two months [2].