The state of gray forest soils, conditioned by microclimatic variability, in the south of the forest-steppe of the Central Russian Upland

Abstract

Aim: The present study aimed to address the issues, relating to indicators of the soils state in conditions of climatic dynamics for the forest type phytocenoses of the south of the forest-steppe of the Central Russian Upland. Materials and Methods: The terrain of the studied area is a river valley of the Seversky Donets. A field study of soils and laboratory soil diagnostics were the basis of the research methodology. Soil survey data were analyzed for the period from 2011 to 2014. Chemical analysis of soil samples was carried out at the Federal State Funded Research Institution “Belgorod Agricultural Research Institute.” The geoinformational system ArcGis (in ArcMap software) with satellite mapping was used to prepare the map of the study area on the right bank of the river Seversky Donets 9. Results and Discussion: In the south of the forest-steppe of the Central Russian Upland, on the right bank of the river Seversky Donets, a certain regularity in the spatial arrangement of the subtypes of gray forest soils is observed: Gray forest soils are formed on the steep slopes (from 5° to 18°) of the north-eastern, north-north-eastern, and eastern exposures, in forest phytocenoses; and dark gray forest soils are formed on the upland and upper slope territories (from 0° to 5°). When calculating microclimatic parameters, it was established that the amount of multiyear temperatures over 10°C on slopes decreases with increasing their steepness. Humidity factor increases with the steepness of the slope in the northeast and north-north-east directions; the reverse pattern is noted for the eastern slope. Conclusion: Dark gray forest soils have a thickness of humus horizon from 42 to 52 cm. They have a higher level of fertility that is expressed in a low value of hydrolytic acidity, in a higher content of calcium and magnesium in the absorbing complex, compared to gray forest soils under the conditions of given forest phytocenosis. In both soil subtypes, a very low content of liable phosphorus, mobile potassium, and nitrate nitrogen was observed.