Characteristics of Root Distribution for Three Kinds of Plants under Different Irrigation Treatments in Drift Desert

Soil water conditions would determine plant root distribution and influence plant growth. To explore the suitable soil water conditions for different kinds of drought-resistance shrubs, we studied root distribution characteristics of Haloxylon ammodendron, Nitraria sibirica Pall. and Calligonum mongolicum under different irrigation treatment in the hinterland of Taklimakan Desert. At the more irrigation amount in one time, H. ammodendron had more root biomass, fine root surface area, the deeper of the root distribution layer and the deeper of the peak value of the fine root surface area, the root distribution of C. mongolicum shifted to the horizontal direction of the surface layer. The spatial root distribution of N. sibirica Pall. were all between C. mongolicum and H. ammodendron, the less amount of annual irrigation of N. sibirica Pall, the more root biomass and fine root surface area and the peak value of fine root surface area shifted to the surface area. In conclusion, the best irrigation treatment of H. ammodendron was as follows: the irrigation time was 14 hours, irrigation interval was 20 days in spring and autumn and 15 days in summer, the total amount was 661.5 kg, the rate of saving water was 17%; C. mongolicum and N. sibirica Pall. were 6 hours per time, 15 days in spring and autumn, 5 days in summer, the total amount was 588 kg, the rate of saving water was 26%. These results may help to establish scientific irrigation management for sustainable development of Tarim desert highway.