The Study Of Helianthus Tuberosus L. For Highway Greening In Saline-alkali Region In Cold Areas And Landscape Evaluation Of The Configuration

In the western part of Heilongjiang Province, most highways were built in the saline alkali region, of which a large part in the worse situation. For a long time, the greening of them is a big problem. Due to the lack of adaptable green plants, the vegetation grew tiny in saline-alkali soil along most of the section of the highways. The naked highway slope is common in severe salinity-alkali region, which cannot protect the highway roadbed effectively, to say nothing of esthetic sense. The study is in according to the previous research result that Helianthus tuberosus was proved to be suitable for the vegetation restoration of the Songnen saline-alkaline grassland, and aiming to make sure the specific H. tuberosus strain for the mid and severe saline-alkali sections through strains selection and exhaust resistance experimentation along the Du-Meng section, provincial highway Linzhao. And then, make sure the best planting method, provide plant configuration, implement along the Dumeng section and evaluate the landscape effect by AHP (the Analsis Hierarchy Process) method.The results are as followed.1. The6H. tuberosus strains screened out in the previous study which is suitable for the highways in saline-alkali region all can grow normally on the slopes of the highways in the saline-alkali region. In the mild saline-alkali sections, DL-2strain has the best performance. In the severe saline-alkali sections, the growth condition of every strain deteriorates significantly, but DL-5strain has the best growth performance and greening effect.2. The experimental results of different concentration and time of automobile exhaust fume gas show that6H. tuberosus strains all have strong ability of resistance to exhaust, which is similar to Cosmos bipinnata, a plant commonly used for the highway greening.3. The best way to greening the slope of the saline-alkali section with H. tuberosus is bunch planting, bunch-seeded with100cm space between plants and50cm in row in the autumn.4. In the weak saline-alkali sections, H. tuberosus can be configured with woody plants like Populus alba, P. opulus alba var. pyramidalis and Amorpha fruticosa and herbs°like C. bipinnata and Iris lacteal var. chinensis to build a composite structure form made by arbor, shrub, herb three layers, forming relatively abundant highway landscape. In the mild saline alkali sections, H. tuberosus can be configured with saline-alkali-tolerance shrubs like A. fruiticosa and Lycium chinense and herbs like C. bipinnata and I. lacteal var. chinensis to build a two-layer plant configuration mode. In the severe saline-alkali sections, only herbs can grow up there and almost only H. tuberosus and I. lacteal var. chinensis are ornamental, but H. tuberosus is better.5. Use the AHP method and Delphi method to build a landscape evaluation system formed with4layers and17evaluation index, with which to take the landscape evaluation of the slopes of the highways in saline-alkali region which were mainly greened with the H. tuberosus. The composite score of the weak saline-alkali sections is8.1253, the landscape quality is rating for Class Ⅰ, the landscape quality is outstanding; the composite score of the mild saline-alkali sections is7.2758, the landscape quality is rating for class Ⅱ, the landscape quality is good; The composite score of the severe saline-alkali sections is heavy saline sections is5.8942, the landscape quality is rating for class Ⅲ, the landscape quality is general.