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Doctorat
États-Unis
1976
SAND STABILIZATION BY AFFORESTATION IN AL HASSA OASIS, SAUDI ARABIA
Titre : SAND STABILIZATION BY AFFORESTATION IN AL HASSA OASIS, SAUDI ARABIA
Auteur : Abo Hassan, Atalla Ahmed
Etablissement de soutenance : Michigan State University
Grade : Doctorat 1976
Résumé
Al Hassa, an important agricultural oasis in eastern
Saudi Arabia, is threatened by moving sand dunes from the
north. In the past the loss of cultivated land to the moving
sand had averaged more than two hectares per year. In
1962, the Sand Control Project was initiated by the Ministry
of Agriculture and Water in Saudi Arabia to stop the sand’s
progress, protect the cultivated land at the oasis and its
water resources, improve climatic conditions, improve the
status of the people living in the oasis, and encourage them
to increase their cultivated land.
Early efforts at controlling the moving sand
included mechanical and physical methods. The mechanical
methods included transposing and trenching. In transposing,
the sand dunes in a particularly threatened area were moved
by trucks or other means to other locations. In trenching,
the sand dune surface was scarred with a bulldozer to destroy its symmetry, so that the moving sand would accumulate
in the trenches. These methods did not prove feasible
for large scale application.
Physical stabilization methods included covering the
sand with asphalt, high gravity oil, mud, a combination of
rubble and cement, mud and rubble, and concrete. Generally
these methods proved to be unsatisfactory. A common problem
was that each of these materials was easily broken by animals
and vehicles and also cracked and fell into fragments
in a short time because of high soil surface temperatures.
Also, they were expensive and needed to be repeated quite
often ; therefore, they are not applicable for large scale
stabilization.
Among agricultural methods that were tried, sowing
grass was effective but slow and expensive, so it was discontinued.
Afforestation, both with and without irrigation
was also attempted beginning in 1963. This study was
conducted at the Al Hassa Sand Control Project in eastern
Saudi Arabia, to evaluate sand stabilization by afforestation
methods. Initially, six species were used :
Tamarix aphylla,
Tamarix gallica, Acacia cyanophylla, Parkinsonia aculata,
Prosopis juliflora and Eucalyptus
camaldulensis. These
species are drought resistant, saline tolerant, and they
can withstand the wide air and soil temperature extremes
that often occur.
Page publiée le 30 janvier 2021