The current state of fertility of degraded soils in the Republic of Tyva

Abstract

The irrational use of pastures in the Republic of Tyva has led to the degradation of pasture lands against the background of soil degradation. In 2023, soil and geobotanical studies were conducted in six districts (kozhuuns) of the Republic of Tyva, which aimed at determining the current fertility status of degraded soils in the republic under conditions of climate aridization. In connection with this goal, the following tasks were solved: identification of typical degraded sites (polygons) to study the erosion processes in various soil and climatic zones – in the mountainous steppe of the Khemchik basin (polygons Aksy-Barlyk, Aldan-Maadyr, Suk-Aksy, Tev-Khaya) and in the foothills of Sangilen (Samagaltai); on the flat areas of the steppe of the Ulug -Khem basin (Sukpak, Tos - Bulak), the dry steppe and desolate steppes of the Ubsunur basin (Moren, Erzin); morphological description of soil sections of the study sites; conducting a geobotanical survey of the territory of the identified polygons; assessing the agrochemical properties of disturbed soils; determining ways to restore the fertility of the degraded lands. The investigations have established that the disturbed chestnut and alluvial soils are low-yielding, cha racterized by a very low content of organic matter. These soils also have a slightly alkaline reaction of the environment due to the close occurrence of the ВСа carbonate horizon and the predominantly exudational water regime. The content of ammonium nitrogen is very low, and the mobile forms of phosphorus and potassium vary significantly across the studied sites. To restore the potential fertility of these soils, it is necessary to introduce pasture rotation, surface improvement measures and water reclamation.