南方红壤试验小区乔灌草多年水土保持效应比较

Multiple Comparison of Effect of Tree,Shrub and Grass in the Plot on Soil and Water Conversation in the Red Soil Area of Southern China

不同植被水土保持效应的评估是水蚀区生态修复理论研究和管理决策的重要依据。基于我国南方典型水土流失区福建省长汀县河田镇2003—2010年葛藤、乳源木莲、胡枝子、百喜草、宽叶雀稗和对照共6个小区的逐月径流深度、土壤侵蚀量及对应的降雨数据,采用植被小区与对照小区的径流深度比值和土壤侵蚀量比值,研究不同植被小区的水土保持效应,并分析降雨对小区水土流失的影响。结果表明,由于植被结构以及根系和地表枯落物的差异,各植被的水土保持效应存在显著差异,植被的保水和保土效应均为葛藤和乳源木莲优于胡枝子和百喜草,而宽叶雀稗最差,各植被保水效应差异较保土效应差异更为明显。径流深度主要受降雨量的影响,不同植被小区径流深度与降雨量的线性关系方程决定系数(R2)均在0.9以上;而土壤侵蚀量与降雨量的线性关系方程决定系数(R2=0.3～0.8)则因各小区植被覆盖的不同存在较大差异。研究结果可为当地和相似地域的植被重建工作提供参考。

Assessing the effects of vegetation on soil and water conversation is the key basis for research and management of ecological restoration in water-eroded areas. In this study, the runoff depth, soil loss and corresponding precipitation of five plots planted with Pueraria lobata, Lespedeza bicolor Turcz, Manglietia yuyuanensis Law, Paspalum natatu Fliigge, Paspalum wettsteinii Hackel, respectively, 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 and soil loss in vegetated plots to the counterparts in the control plot. Meanwhile, the effect of rainfall on the soil and water loss was also analyzed. The results showed that the effects of Pueraria lobata and Manglietia yuyuanensis Law on soil and water conservation were better than those of Lespedeza bicolor Turcz and Paspalurn natatu, while the effect of Paspalum wettsteinii Hackel was the worst. The differences of effects of water conservation were more significantly than those of soil conversation between five kinds of vegetation. The runoff depth was mainly affected by rainfall, and the determination coefficients （R2） of linear regression models between rainfall and runoff depth of all planted plots were all greater than 0.9, whereas the determination coefficients of the linear regression models between rainfall and soil loss varied from 0.3 to 0.8 for different vegetation plots. These results provide a reference for vegetation reconstruction in the current and similar areas.