关键词: 沙漠人工植被, 细根, 粗根, 分布, 动态

Abstract: In plant growth season of 2004, root system distributions and dynamics of 4 types communities collocated Artemisia ordosica and Caragana korshinskii were sampled by root corer to measure. Simultaneously, coarse root profiles in semi-fixed dunes were investigated with method of digging root system by layers. The results show that the dynamics of fine root of communities can be expressed as two-peak curve though the peak values appear at different date in the 4 quadrats. The fine roots of A. ordosica quadrat mostly distribute in 0~40 cm soil layers, but those of other quadrats densely distribute in 10~60 cm soil layers. The maximums of root length density (RLD) and root weight density (RWD) of 4 quadrats in surface layer (0~30 cm) occur due to annual plants developing. The root system data in depth of 300 cm were gained with method of combined irrigation with sample by root core, it show that 90 percent of fine root of 4 quadrats locate in 0~200 cm layers, and the deepest roots of A. ordosica quadrat arrive to 270 cm and those of other 3 quadrats more than 300 cm. Both of RLD and RWD of fine root minish with depth and the relationships can be described by exponential equation（P<0.01）. The root nodules maximums occur in April except for A. ordosica quadrat, and RLD of coarse roots are far little than those of fine roots. The results of digging channel and sampling by layers show that the ratios of root/crown A. ordosica are higher than that of C. korshinskii. The RLD of coarse roots of C. korshinskii mostly distribute in 0~60 cm soil layer and RWD concentrate in 0~40 cm soil layer, both of A. ordosica are not deeper, and distribute in 0~40 cm and 0~20 cm soil layer, respectively.

Key words: re-vegetated communities in desert area, fine roots, coarse roots, distributions, dynamics