乡土植物灌木化建植是高速公路边坡防护的重要途径。为了探明西南地区5种典型边坡植被配置模式的护坡性能及年际间差异，拟以成渝高速永川段K309+145~K309+370处为试验观测区，以景观过渡带(小乔木、地被植物)+坡面防护带(灌木、草本植物)的群落结构为基础，对比研究2010-2012年间各植被配置模式在自然降雨条件下的产流、产沙特征及年际间差异。结果表明：1)建坪初期，一年生草本植物狗尾草(Setaria viridis)所在的草灌混合群落(M5)生长快、成坪早，在2010年汛期即表现出较强的护坡性能：蓄水、保土能力分别达到59.14%、96.22%，产流量、产沙量(61.2 mm,52.0 g·m-2)也明显低于其它小区(P＜0.05)；狗牙根(Cynodon dactylon)、黑麦草(Lolium perenne)等多年生草本所在群落(M3、M4)成坪迟、生长慢，护坡性能普遍较差。2)在2011年汛期，多年生草本植物所在群落(M1~M4)的护坡性能较2010年明显提高，以M3、M4即苜蓿(Medicago falcate)+狗牙根、小冠花(Coronilla varia)+黑麦草最为显著。3)2012年汛期，具有发达根系结构的狗牙根所在群落(M3)护坡性能最强：蓄水、保土能力分别达到80.03%、98.49%，产流量、产沙量分别为32.40 mm、17.67 g·m-2)；M5的护坡性能最差,其产流量、产沙量(62.1 mm,150.33 g·m-2)也明显高于其他观测区。可以看出，在种植密度、建植措施等建群条件相同条件下，植被的护坡性能与其群落结构有关：建坪初期，护坡性能与地上生物量大小正相关(r2≥0.987)，后期则与根系重量正相关(r2≥0.998)。%Using localization shrubs to reconstruct plant communities is an important ecological mode in superhighway side slope protection. In this case, taking Chengyu expressway in Yongchuan region ranging K309+145 to K309+370 and five typical vegetation modes, including landscape transitional zone (ornamental arbors+ground-cover plants) and slope protection zone (shrubs+herbages), in southwest areas as the example and foundation, their characteristics of runoff and erosion sediment in rainy seasons during the year 2010 to 2012 were investigated, and the annual fluctuation of their ecological slope protection capacity was analyzed. Results showed: 1) the annual herbaceous plants in the grass-shrub community, i.e., Vitex negundo + Setaria viridis grew rapidly, which turf-establishment stage (65 d )was transitory, its capacity of soil and water conservation (80.03%and 98.49%,respectively) was the highest than other modes in the first growing season after turf-establishment(2010), and among five vegetation modes, its runoff and sediment yield (61.2 mm and 52.0 g·m-2, respectively) was the lowest (P<0.05). However, the perennial herbs(e.g., Cynodon dactylon, Lolium perenne and so on)in the grass-shrub communities grew tardily with more laggardly turf-establishment stages, and their outstanding capacity of soil and water conservation were only showed in the second or third growing season after turf-establishment. 2) during the rainy seasons in 2011, ecological protection benefit of the grass-shrub communities (M1-M4) including perennial herbs were improved apparently, which were especially outstanding in Coronilla varia+Lolium perenne(M4)and Medicago falcate+Cynodon dactylon (M3). 3) In third growing season(2012), performance of artificial vegetations Medicago falcate+ Cynodon dactylon (M3)was the most excellent in slope protection by means of developed root system of Bermuda grass, its capacity of soil and water conservation was 80.03% and 98.49%, its runoff and sediment yield was no more than 32.40 mm and 17.67 g·m-2, respectively, and in contrast , that of M4 was the worst in the slope plot experiments where given artificial vegetations were planted. Therefore, it can be seen that ecological protection benefit of artificial vegetations was closely related to their community characteristics, there was a positive correlation between the aboveground biomass of vegetations and their capacity of soil and water conservation in initial succession with determination coefficient (r2) in excess of 0.987, and did so between root biomass and these capacity in latter succession(r2≥0.998) when there were the same side slope conditions, seed quantity and planting measures.
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