云南蒋家沟泥石流区干热退化山地引种拟金茅的技术与效果

蒋家沟是我国西南山区一条典型的暴雨型泥石流沟，每年雨季爆发泥石流12～20次以上，每年冲出沟口的固体物质总量平均达100万m3～300万m3，给当地工农业生产造成严重经济损失。蒋家沟在内外营力作用下，生态环境严重恶化，泥石流等山地灾害日趋严重。拟金茅生态适应性强，能耐干旱瘠薄。在蒋家沟退化山地采用分株繁殖、种子直播和育苗移植等方式引种拟金茅试种成功。生长发育快，经济效益高，改善环境效果好，推广应用前景广阔。

TECHNIQUE AND RESULTS OF COMMON EULALIOPSIS' APPLICATION ON XEROTHERMIC DEGRADED MOUNTAIN IN JIANG JIA GOU DEBRIS FLOW GULLY

In Jiang Jia Gou gully, the height drop is 2 227 m, the percentage of forest cover is only 8.59%, the average gradient is in the range of 35°～45° and the slope cutting density is 6.35 kw/kw2. There are 200 or more lateral ditches in different sizes in Jiang Jia Gou, and the loose solid material reserves of its upper and middle reaches are about 1.23×109 m3 . Under the effects of inside and outside stress, debris flow takes place 12～20 times per year, making the percentage of exposed field get to 26.1%. The ecosystem in Jiang Jia Gou keep in degrading and it is very difficult to restore vegetation there. Common Eulaliopsis ( Eulaliopsis binata ) basal leaf sheath and flower head are densely fluffy, while Common Eulaliopsis has the characteristic of drought enduring and the adaptability of growing in poor soil. In Jiang Jia Gou gully, we have succeeded in planting the introduced Common Eulaliopsis in breeding holes, contour ridge and contour trench by the method of plant division breeding, direct seeding and seedling transplantation. Seedlings drought - resistance preserve rate is 2 times more than that of self-grown grass when Common Eulaliopsis is applied in slopes where debris content is greater than 40 %. Survival rate and preserve rate of seedling transplantation are 1.4 times and 2 times, respectively, that of direct seeding. In this method, the percentage of grass cover can get to 80 %, the yield of hay is 5 602.8 kg/hm2, and the thickness of surface litter layer is 2～3 cm. We also find the content of soil organic substance can increase 16 times, the base of grassy can retain debris and sand layer thick in 2～3 crm, and the root of it, which is as long as 0.5～1 m, can fix soil of 0.2～0.3 m3. In contrast with exposed field, the grass field with Common Eulaliopsis can lower the land temperature to 48 % of former field, increase the moisture content and porosity of soil to 3.2 times and 1.6 times respectively. Experiments shows that introducing Common Eulaliopsis to Jiang Jia Gou debris flow gully can improve the slope' s stability and have good environmental effects. Also, it needs only one year to plant Common Eulaliopsis, but can get profit in following several years. Common Eulaliopsis' tender grass can be used as feed or fertilizer; its hay can be used as the raw materials of grass weaving and pepermaking. The hay income can get to RMB 1680～1935 yuan/hm2. It is easy to shake off poverty and build up a fortune by planting Common Eulaliopsis, and it has a great applying perspective.