Study On The Establishment Of Vegetative Cover Of The Qinghai-Tibet Railway Base From Dang Xiong To Yang Bajin

An experiment was carried out in Yang Bajin Town, which simulated the enviroment of the railway base slopes and 13 kinds of herbaceous plants were sown alone and 5 kinds were sown with compounds of them. There were totally 18 kinds of cold-resistant and drought-resistant herbaceous plants were selected in this experiment. The results were as follows:(1) Because of the terrible climate there, the small enviroment of the railway base slopes was even worse. The growth and development of the species from the pulse family were limited. Compared to the warm place ,the seed quantity should be increased in order to retrieve the individualities'hypodevelopment by the population dnensity.(2) Among all the species Elymus nutans Griseb and Rumes K-1 performed best with higher germination rates seperately 97.5%, 95%, coverage rates 87.8%, 71.2% and overyearing rates 97.5% and 100%, which showed that they both had strong tolerance to the oxygen deficiency, higher evaporation capacity and great temperature difference between day and night, so they had good adaptability to the enviroment of the railway base. According the previous study, Elymus nutans Griseb and Rumes K-1 were the predominant species in the artificial grassland here. There were many studies on the models of their introduction and growth and at the same time people also found Elymus nutans Griseb had a good performance when it was sown with other species. Therefore, Elymus nutans Griseb and Rumes K-1 both could be uesed as the basic species to be planted on the railway base slopes.(3) Symphytum asperum which was with deep and perennial roots, not only had a good germination rate(100%) and overyearing rate but also had adaptation reaction for the alpine cold wheather. However, its invasion speed was not that good and the vegetative coverge was lower(the average coverage degree was 39.8%), so it should be sown with other Gramineae grass which had higher invasion capacity and higher coverage degree.(4) The local grass Elymus sibiricus Linn had a germination rate 93.4%, which was a little lower compared to Elymus nutans Grise, Symphytum asperum and Rumes K-1, but its coverage degree(61.4%) was higher than Symphytum asperum. It had some advantages to other species from other places. As a result, it could be sown with other species to increase the complexity and stability of the community.(5) The 5 turfgrass species performed well in the first year, but their overyearing rate were low and degenearted quickly. They can only be used as the pioneer species or short time species. Meanwhile the result showed: Slender Wildrye, Elymus breviaristatus (Keng) Keng f., Agropyron cristatum (Linn.) Gaertn., Festuca arundinacea Schreb, Festuca ovina, Festuca elatior L., Psathyrostachys juncea (Fisch.) Nevski, Festuca sinensis Keng and Medicago sativa.