Fine-root biomass, production, turnover of Ulmus pumila, Populus sibirica, Hippophae rhamnoides and soil organic carbon in Mongolian Semi-Arid Steppe

Abstract

Implementing reforestation and forest restoration measures is the most effective way to counter desertification and land degradation in low-precipitation steppe regions. The study area, situated in Argalant soum, Tuv aimag, is a grassland that is strongly affected by desertification in the steppe area. From a phytogeographic perspective, the area is described as a Middle Khalkha semi-arid steppe (dry steppe) region. Selecting tree species that can adapt to the local environment is crucial for successful afforestation efforts. Fine roots were measured in sequential soil layers 0–40 cm depth increments across a total of 216 samples in the afforestation site, and 60 soil samples were collected in sequential layers from 0 to 60 cm in depth at the afforestation and control sites. This study showed that Hippophae rhamnoides had higher fine root biomass accumulation (1.689 g m^–2), renewal rate (1.071 yr) and productivity (0.949 g m^–2). For Populus sibirica and Ulmus pumila, their fine root development showed similar results. However, three different tree species accumulated different amounts of soil organic carbon. U. pumila (51.16 Mg ha^–1) increased the soil carbon stock by one time compared to the other two species. It is necessary to select and plant tree species that have a significant impact on increasing fine-root biomass, productivity, soil fertility and soil organic carbon stocks in the arid steppe regions of Mongolia.

Keywords: semi-arid; afforestation; fine root production; fine root turnover over-rate; soil organic carbon