Soil Stabilizing Capability of Three Plant Species Growing on the Three Gorges Reservoir Riverside

Plant regrowth capacity and soil protection were investigated using three flooding-tolerant Yangtze River riverside species (Arundinella anomala, Hemartria compressa and Cynodon dactylon). The root and leaf surface growth, the plant regrowth capacity and the mitigation of soil runoff were analyzed using potted plants that were covered with 5, 10 and 18 cm new sediments, respectively. A. anomala reacted most slowly to the recovery from new sediments, while H. compressa had the highest recovery rates. The latter could produce 24 times the initial root length and 41 times its original leaf surface during the growth period of 12 weeks. C. dactylon showed no significant change in growth in relation to the rising sediment thickness, which means that even 18 cm of new sediments were tolerated by C. dactylon. Erosion tests showed that all three plant species can reduce the soil runoff by more than 63%. Compared to other species, A. anomala was less capable of stabilizing new sediments. The soil protecting abilities of H. compressa decreased after more than 10 cm of new sediments. C. dactylon showed the best soil retention compared to the other species examined, since it could reduce the soil runoff up to 87%. Consequently, C. dactylon was found to be significantly better for soil-protection plant species than A. anomala and H. compressa given the conditions at the Three Gorges Reservoir.