Root distribution characteristics of Ammopiptanthus mongolicus community in Ulan Buh Desert

The method of oven-drying and stratified digging was adopted to study the dry mass and length of roots of varied diameters of Ammopiptanthus mongolicus and its associated plants in the community, and the spatial differences in root distribution of different plants at different soil depths were analyzed in A. mongolica community in Ulan Buh desert.The results showed that there are four types of root systems based on their distribution depth for the seven plants in this community. The shrub A. mongolicus has the deepest root, which was mainly distributed in soil up to 120 cm. The root of two sub-shrubs, Artemisia xerophytica and A. ordosica, were mainly distributed within 80 cm and 70 cm depth, respectively. The root of the perennial herb Oxytropis neimonggolica was mainly distributed within 50 cm depth. Two perennial herbs, Jurinea mongolica and Allium mongolicum, and the annual herb Corispermum mongolicum have shallow root systems, which are mainly distributed within 30 cm, 20 cm, and 10 cm depth, respectively. The order of the maximal root depth was: A. mongolicus (160 cm) > A. xerophytica (130 cm) > A. ordosica (100 cm) > O. neimonggolica (80 cm) > J. mongolica (30 cm) > A. mongolicum (20 cm), and C. mongolicum (20 cm). Therefore, utilization of soil water in different soil depths is achieved through spatial differences in the distribution of roots having different diameters, which promotes the coexistence of species and improves plant diversity in A. mongolicus community.