THE CONVERSING EFFECT OF AERIAL SEEDED VEGETATION ON THE MOVING SAND DUNE CHAINS IN YULIN AREA OF MAOWUSU DESERT

The measurements of synchronous and relative value of wind velocity were conducted with 56 probes of 4 levels in aerial seeding land and moving dunes in Yulin area of Maowusu Desert in 1988. The result showed that the conversing effect of aerial seeded Hedysarum mongolica Turcz. and Hedysarum scoparium Fisch et Mey., especially that of H. mongolica was remarkable. The former vegetation belt was widened from 24 metres to 35 metres because of germination of the subterraneous stem. The rate of survival area increased from 17.7% to more than 60% 10 years later and the land changed into stablized sand land.As for the reformed dune, its slope became smaller, its length became longer, its height became lower, it went forward in a tongue-shaped form and the land between dunes became smaller. A series of changes of the topographic features of aerial seeding land occurred. The wind velocity there was reduced horizontally, vertically and harmoniously. That the result of closing the moving dune after 10 years was still without vegetation on slope but the dune went forward. Thus, aerial seeding in the farther place and artificial seeding in the near place are considered to be good methods to control the dunes. It should be promoted in the future.