Successful Biological Methods for Combating Desertification at Degraded Areas of China - Combating Desertification in Asia, Africa and the Middle East - page 59

Main Wind Direction
Sand Fix Forest
1000m

Sand Closing Belt
100-300m

Sand Stock Belt
30-50m

Network
in
farmland

Fig. 3.4 An integrated approach to sand fixation in an artificial oasis threatened by encroaching
sand dunes

Main Wind Direction

Sand Barriers and
Sand-Closing Belt

Tree Sand-stocking Belt
Opening

Sand Barriers and Shrub Sand-Fixing Belt

Belt Farm land

12-16m 12-16m

200-500m 100m 30-50m 20-30m 10m

Fig. 3.5 Comprehensive Shelter system in Gaotai county, Gansu

5.1 Oasis Protection

There are some example models for protecting oases:

Example 1. Comprehensive control of shifting sand in Xishawo, Minqin County
(Fig. 3.4 ).

5.2 Tree Belts to Trap Sand

Establishing the fixed and semi-fixed dunes (constituted by the sand mounds
covered by Ta m a r i x l a x a and Nitraria tangutorum close to farmland, forms the
belt for protecting natural vegetation. In the section attaching to mobile sand dunes
on the periphery of closing belt, Russian olive and poplar are planted as patches
in lowlands among dunes to encircle the dunes, clay or wheat straw barriers are
constructed in grid or line and Haloxylon ammodendron is planted within barriers
on dunes.

Example 2. Comprehensive control of shifting sand in northern bank of Heihe River
in Gaotai County (Juba and Shiba villages as examples) (Fig. 3.5 ).

Sand-stocking forest belts, 12-16 m wide per belt, are planted with trees ( Populus
gansuenis and Elaeagnus angustifolia ) in the sand area close to farmland; there is an
interval of 10 m between neighboring belts. Forest multi-belt for stocking sands is
planted with trees and shrubs along the forward line of mobile dunes. Based on the
construction of sand barriers, shrub forest for fixing shifting sands is planted with