EVOLUTION DE LA SALINITÉ DANS LES PÉRIMÈTRES DE MISE EN VALEUR ET CONSÉQUENCES SUR LA DIMINUTION DES RENDEMENTS DU BLÉ DANS UNE RÉGION SAHARIENNE: CAS DE LA RÉGION D’ADRAR

Abstract

The development of Saharan agriculture in Algeria by the creation of the irrigated perimeters was confronted with enormous problems which affect the agricultural production. The latter are directly related to the technical route which is not controlled and sometimes nonappropriate to the Saharan context pedoclimatic. Indeed, modern agriculture is introduced according to a model borrowed without adaptability. It results from it after some campaigns from irrigation, a very significant salinisation of the grounds whose level reached, largely exceeds the tolerance level of the culture. The main aim of this work has been to make a quantitative analysis of the evolution of the salinity of the grounds irrigated by pivot for a few years, and to evaluate its intensity on the reduction in the corn yields. For that, three perimeters irrigated respectively since 2,3 and 4 years are studied and compared on the pilot ground not irrigated. For each piece, the evolution of salinity is studied between two periods of the vegetative cycle of corn, the initial state corresponds at the stage tillering and the final state corresponds at the stage maturation. The irrigation is done by sprinkling with a mineral-bearing water of the tablecloth albienne. The results obtained show that water of irrigation is characterized by a strong salinity and a weak danger of sodicity. The sodium contents and chloride are excessive in mode of irrigation by sprinkling. The evolution of the salinity of the grounds irrigated since 2,3 and 4 years on a crop year scale, is highly significant as from the fourth year and exceeds the tolerance level to the salinity of durum wheat. The salinisation thus constitutes one of the independent factors responsible for the reduction in the corn yields. Indeed, an increase of 1 dS/m causes a fall of the output in grains of 4 q/ha.