Study On Community Character And Soil And Water Conservation Effect Of Protection Slope Vegetation On Freeway Slope

Selected eight varieties shrub and herbage of adapting to local climate, such as Agropyron cristatum L., Caragana Korshinskii Kom., Puccinellia tenuiflora (Gnseb.)Scribn. et Merr., and so on. The course of experiment was from July, 2005 to November, 2006. The slope of NingDa Freeway in Qinghai province was the experiment site. The objective of the study was to sort out mixed planting combination and species which adapted to local climate in Qinghai province. Maked use of outside planting, observation and inside analysis methods. Compared and analysed the soil and water conservation effect of different combination on freeway slope. The outcome showed that, in the same year of planting and the next year, the aboveground biomass and average canopy on schatten seite were more than it on sonnen seite. On schatten seite, the aboveground biomass and canopy increased the most quickly were the combination of Agropyron cristatum L. + Puccinellia tenuiflora (Gnseb.)Scribn. et Merr. + Hippophae rhamnoides L., canopy from 10% to 100%, the capability of improvement soil structure were the best, and the soil and water loss was little in the next year of planting, so it was an all-right combination of mixed planting. And the canopy of Leymus secalinus Georgi.+ Caragana Korshinskii Kom. increased from 5% of the last growth season in the same year of planting to 90% of the last growth season in the next year, and the species diversity index was higher, so that the protection slope potential was better, next to Agropyron cristatum L. + Puccinelliatenuiflora (Gnseb.)Scribn. et Merr. + Hippophae rhamnoides L. in the next year of planting.By general appraising from cooperation between member of mixed planting combination, rate of growth, biomass, interception rate of aboveground, reinforcing Anti-scourability of underground and slowering runoff of litter, the outcome showed that Agropyron cristatum L. + Puccinellia tenuiflora (Gnseb.)Scribn. et Merr. + Hippophae rhamnoides L. were the best combination, secondly, Leymus secalinus Georgi.+ Caragana Korshinskii Kom. were the better combination too.At single plant point, Hippophae rhamnoides L. was selected firstly in the species of shrubs, and Medicago sativa L. was selected firstly in the species of shrubs and herbages respectively, on freeway slope protection. However, Peganum harmala L. was the best ill-fitted.To sum up, in the period of two years of planting, the herbage plant showed the important function of protection slope, the shrub effect was insignificant excepe Hippophae rhamnoides L. on schatten seite. With the competition and succession, the protection slope effect of the shrub become stronger and stronger, so the protection slope effect of mixed planting combination of herbage and shrub had a change course from herbage initially to rational combination of shrub and herbage.