Science et changements planétaires / Sécheresse


The secondary salinisation of soils in the Sahara. Its impact on the durability of agriculture in the new development perimeters Volume 14, issue 4, OCTOBRE-NOVEMBRE-DÉCEMBRE 2003


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Institut national agronomique (INA), El Harrach, Alger, Algérie <k.djiliina.dz> ; <ka_djiliyahoo.fr> Centre de recherche scientifique et technique sur les régions arides (CRSTRA), Front de l‘oued, BP n°1682 R. P 07000 Biskra, Algérie Institut national de la recherche agronomique (INRA), Station de Mahdi Boualem Baraki, Alger, Algérie

The characterization of the salinity state of the soils of two fields located in a Saharan milieu showed that irrigation by variously mineralized waters is followed by a salinisation of the soils, in particular in their surface horizons. Indeed, results indicated that the salinity, which was initially lower than 2 dS\m in surface horizons, increased to more than 12 dS\m after five irrigation campaigns. The intensity of the salinisation is correlated to the quality of the irrigation water. The study of the spatial distribution of the salinity revealed a variable heterogeneity in relation with the quality of the irrigation water and with the horizons considered. This study also showed that secondary salinisation is a factor of soil degradation, substantially reducing cereal crop yields. In fact, the salinity tolerance level of the main durum wheat cultivars used in these regions is generally reached through the initial salt concentration of irrigation waters. Moreover, the irrational use of water and land resources encourages the conservation and proliferation capacities of some depredators. These practices therefore seem to be unsuitable to the oasian environment and constitute a threat for its future.