Study on the Determination of Salt-tolerance Index of Main Afforestation Tree Species and Their Ordination in Arid Areas with Secondary Salinization

The research on the slat-tolerance index of main afforestation tree species in arid and semi-arid areas with secondary-salinization was carried out during the year 1991～1995,and the index of salt-tolerant were as follows: Populus enphratica Oliv.8 g/L P. alba var pyramidalis Bge.6 g/L Lyeium chinese Mill.7 g/L Tamarix ramosissima Ledeb50 g/L Hedysarum scoparium Fisch.et Mey.5 g/L Hedysarum mongolicum Turcz.6 g/L Elaeagnus angustifolia L.4 g/L Hippophae rhamnoedes L.6 g/L Haloxylon ammodendron(Mey).Bunge30～50 g/L Pyrus betulaefolia Bge.4 g/L Caragana intermedia Kuang et H.7 g/L The ordination for capability of salt-tolerant species is from strong to weak: Haloxylon ammodendron,Tamarix ramosissma,Populus enphratica,Lyeium chinese,Caragana intermedia,Hedysarum mongolicum, Hippophae rhamnoides,Populus alba,Hedysarum scoparium,Elaeagnus angustifolia and Pyrus betulaefolia.