Using Isotopic Labeling to Investigate Artemisia ordosica Root Water Uptake Depth in the Eastern Margin of Mu Us Sandy Land

Abstract

The annual precipitation in the eastern Mu Us sandy land is about 400 mm, but the precipitation varies greatly between years and seasons and severe meteorological and seasonal droughts often occur, which makes the ecological environment very fragile. Artemisia ordosica is the most dominant species in the area. We used depth-controlled deuterium labeling technology to study the root water uptake depth of adult Artemisia ordosica to explore how Artemisia ordosica can survive in extreme droughts. In addition, the soil moisture content was analyzed after the rainy season in October 2020 and the dry season in June 2021. We found that under the influence of an extreme seasonal drought in the study area, the soil layer below 180 cm in depth still maintained high water content of more than 2%; the dry sandy soil in the surface layer inhibited the loss of soil water below 180 cm. The maximum water uptake depth of the roots of adult Artemisia ordosica can reach 240–260 cm. In periods of drought, Artemisia ordosica can still maintain life by absorbing deep soil water. In drought-prone environments, Artemisia ordosica evolved a deeper vertical root system to survive dry periods by absorbing soil water from deeper layers, showing a broad water intake capacity and strong adaptability to arid environments. This study can provide a reference for afforestation projects and ecological restoration in Mu Us sandy land and also provide a reference for the ecological restoration of coal mining areas in this area.