ЗАПАСЫ ОРГАНИЧЕСКОГО УГЛЕРОДА В ЛЕСНЫХ ПОЧВАХ СЕВЕРНОЙ МОНГОЛИИ

Abstract

Soil organic carbon (SOC) stock and its variation on the regional and large spatial scales are critical for estimating the global SOC inventory and predicting further changes. This study was aimed at estimation of the SOC stock in the boreal forests of Northern Mongolia. The study was carried out in the forested areas of the Bulgan, Selenge and Tuv provinces using a completely randomized design. A total of 900 soil samples from 60 sampling points were col-lected for the laboratory analyses. At each point, a soil profile with a depth of more than 30 cm was laid out, and then soil samples were taken from three soil layers: 0–5, 5–15, and 15–30 cm of each profile. Therefore, the results of the assessment show a high difference of the SOC stock not only between the provinces, but also within each province. The higher SOC stocks were observed in the Selenge (123.5±14.85 t/ha), and lowest in the Tuv (51.23±7.8 t/ha) prov-inces. The estimated SOC stock in the studied regions was 93.77 t/ha on average. We found relatively less SOC stock in the boreal forests of Mongolia compared with the Asian part of Russia including Siberia and the Russian Far East. Such a less SOC stock may be caused by geographical distribution, where the Mongolian forests border the Central Asian dry steppe and frequent water deficit. However, we found that the accumulation of SOC stocks in the boreal forests of Mongolia is largely dependent on the mountain slopes and aspects combined with the distribution of precipitation across the country. Higher amount of SOC stocks were found in north-facing aspects and lower positions with low slopes of the mountains in lower altitude. Consequently, moisture supply basically determines the pattern of the SOC stock distribution in the northern boreal forests of Mongolia. For citation: Tungalag М., Gerelbaatar S., Lobanov A.I. Organic Carbon Stocks in the For-est Soils of Northern Mongolia. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 2, pp. 169–176. DOI: 10.37482/0536-1036-2020-2-169-176