The Effect of Grazing on the Temperature Regime of the Alas Soils of Central Yakutia

Abstract

There are numerous studies on the effect of grazing on the physical and chemical parameters of soils. However, the impact of grazing on the temperature regime of the alas soils in Central Yakutia is still poorly understood. This paper presents the results of long-term observations of the state of the soil-and-plant cover of thermokarst basins—i.e., alases—located in the Lena-Amga interfluve and actively used as pastureland. Observations of the process of the self-restoration of grass cover and changes in the temperature regime of alas soils were carried out on different variants (with isolation from grazing and without isolation). A significant increase in the average height of the grass stand and its foliage projective cover was observed with a gradual reduction in the number of species when isolated from grazing. Changes in the structure of the alas vegetation cover influence the microclimate of the soil. As a result of livestock grazing, the mean annual soil temperature rises and the amount and depth of the penetration of active temperatures increase. The most severe changes in the temperature regime occur in years with an abnormally high cover of snow. The soil warming observed during grazing undoubtedly has a favorable effect on soil organisms. However, in conditions of climate warming, grazing, especially overgrazing, can disrupt the permafrost regime and thereby provoke or intensify thermokarst phenomena.

Effects of Long-Term Enclosing on Vertical Distributions of Soil Physical Properties and Nutrient Stocks in Grassland of Inner Mongolia

“…The critical diameter of grain will become larger as vegetation coverage decreases and wind erosion intensity increases. Lower grazing pressure resulted in a large amount of vegetation which might have increased surface roughness and thus favored the deposition of fine soil particles carried by the wind [12,28]. This study showed that the grazing treatment decreased (p < 0.01) the amount of silt (2-50 µm) and increased (p < 0.05) the amount of fine sand (100-250 µm) of surface soil (0-10 cm) compared to long-term enclosing, which suggested that surface soil became coarser with long-term grazing in semi-arid grasslands of Inner Mongolia.…”