Studies On The Law Of The Succession Of Vegetation By Aerial Seeding In Mu Us Sandy Land

Mu Us Sandy Land is one of the most active desertification aera in China.Aerial seeding which is a fast and effective measures for the modernization of afforestation,have become the important means of vegetation restoration and reconstruction in Mu Us Sandy Land. Through surery of the seeds of aerial seeding,the sprout rate after the aerial seeded and the community dynamics after the aerial seeded,the main conclusions are as follows:(1) The pills graining seeds and reasonable configuration of sand barrier can effectively prevent the seeds to drift and improve the seeds's ability of natural coated sand.They can also improve the effectiveness of the aerial seeding effectively. The main factor that affect the local sprout is rainfall in June, July and August 3 months . The aerial seeding plants's pattern of sprout is the cluster in the dunes.In different positions of dune,the order of the number of sprout is the the lower side of lee slope >the middle of wind slope>low land>the top of dune>the middle of lee slope.(2)Areial seeding aera consists of 61 species belonging to 19 families and 46 genera. The flora composition area in high degree of broken and it composed fragile. The analysed show: the coverage of aerial seeded vegetation,species diversity and lifeform increased with time year by year. As the years of aerial seeded increased,the aerial seeded community tended complex and became stable.(3) Aerial seeding and grassland fencing are the important measures of forest vegetation recovery. According to the different vegetation restoration of vegetation and the degree of degradation, selection of measures should also be different.(4) According to classification of TWINSPAN, aerial seeding communities have successed the top community of Mu Us Sandy Land after 25 years of aerial seeded.However, the primary vegetation did not happen the corresponding positive succession.It means the aerial seeding has obviously promote to the succession of vegetation restoration.(5) As the years of aerial seeded increased, the soil properties have obvious changed with the succession of vegetation. Soil texture, organic matter and total nitrogen content of vegetation with the aerial seeded year are positively correlated. There are obvious improvement of the soil to the aerial seeding area.