Comparison of Water and Soil Conservation Effect of Trees, Shrubs and Grass in the Red Soil Area of Southern China

Assessing the effects of vegetation on water and soil conversation is the key basis for research and management of ecological restoration on water-eroded areas. In this study, the runoff depth, soil loss and corresponding precipitation of five plots planted respectively with Pueraria lobata, Lespedeza bicolor Turcz, Manglietia yuyuanensis Law, Paspalum natatu Fliigge, Paspalum wettsteinii Hackel and one control plot were observed monthly from 2003 to 2010 in Hetian town of Changting County, Fujian Province, a typical water-eroded area in southern China. Then the effects of different vegetation on water/soil conversation (RE/SE) were determined using the ratios of runoff depth/soil loss between vegetated plots to the control plot. Meanwhile, the effect of rainfall on the water and soil loss was also analyzed. The results showed that, both the water and soil conservation effects of Pueraria lobata and Manglietia yuyuanensis Law are better than Lespedeza bicolor Turcz and Paspalum natatu, while Paspalum wettsteinii Hackel are the worst. The differences of effects of water conservation are more significantly than those of soil conversation between five kinds of vegetations. The runoff depth is mainly affected by rainfall, the determination coefficients (R2) of linear regression models between rainfall and runoff depth of all planted plots are all greater than 0.9, whereas the determination coefficients of the linear regression models between rainfall and soil loss vary form 0.3 to 0.8 for different vegetated plots. These results provide a reference for vegetation reconstruction in the current and similar areas.