Controlling Sand Movement Through Mechanical Measures: China’s Experience - Combating Desertification in Asia, Africa and the Middle East - page 21

with other measures, especially the biological measures. This is where suitable
desert plant species are planted immediately after the shifting sand is fixed so
that permanent solutions can be attained.

Keywords Desertification • Mechanical measures • Sand dunes • Wind
erosion • Land use change • Checker boards • Wind velocity • Transport routes •
Infrastructure • Shapotou • Xinjiang • Gansu • Ningxia • Inner Mongolia •
Tennger/Tengeli desert • Taklamakan desert • Gobi desert • Yellow river • Qilian
mountain

1 Introduction

Shifting sand is one of the serious contributors to desertification in China (Ci and
Ya n g 2010 ). There are two complementary measures used to fix shifting sands.
One is to protect the vegetation on the sand dunes or, where such vegetation has
deteriorated, to plant trees, shrubs and grasses. This type is known as the biological
approach and is dealt with in Chap. 3 . The other method relies on mechanical
measure and is the subject of this chapter.
Sand dunes especially along the fringe of sandy desert encroachment seriously
harms or threatens farmland, villages, irrigation canals, reservoirs, transportation
(highway, railway), mining, etc. It is in these areas that mechanical measures are
suitable as emergency measures to fight against the moving sand dunes. Mechanical
measures are preferable to biological ones under these circumstances. In some
extremely arid areas, subject to wind and sand movement, plants can barely survive
and grow and so in order to prevent sand dune encroachment, mechanical measures
must be taken. If it is desirable to plant trees, shrubs or grasses on the sand dunes in
some areas, mechanical measures should be taken before planting of trees, shrubs or
grasses. Otherwise the seeds or seedlings of the plants will be exposed by wind or
buried by blown sand even if the soil moisture content is available and other natural
factors are suitable for the plants. Mechanical measures, under these conditions, can
prevent sand dunes from moving and guarantee the survival of these seedlings of
the sand-holding plant species.

2 Relationship Between Mechanical Measures

and Biological (Plant) Measures

In general, the service life of mechanical measures is about 3-5 years. They require
regular maintenance after they are set-up. In any case, the effectiveness of desert
control by biological (plant) measures alone is not satisfactory. Therefore, various
sand-holding plant species should be planted after the mechanical measures. In
the ensuing years, especially the first 5 years, these two measures can well be
complimentary in checking wind and controlling sand (Fig. 2.1 ).