Evaluation de la qualité des eaux d’irrigation

Abstract

In Constantine, the re-use of rough used water in irrigated agriculture back to dates 1970 and is always of actuality in spite of the effective law prohibiting the use of these waters. In the course of this study, used water, of the two principal wadis: Rhumel (O.R) and Boumerzoug (O.B), used for irrigation, in two agricultural stations, have been subject of a qualitative evaluation. The stations differ by their geographical place where the influence of human and industrial activity is not the same from one station to another. The methodology followed in the evaluation of the quality of these waters is the one recommended by the FAO. Compared to the directives of the FAO, The results found, have reveale d some "anomalies" that might be at the origin of agronomic problems (salinity), pedological (permeability) and of toxicity,due to excessive contents of sodium, chlor ine, bicarbonate and azote. The problem of salinity is encountered in both stations the result established is that the practice of irrigation of irrigation happens in an anarchic way without any prior study of evaluating water quality. The farmers irrigate several types of cultures without the least control. Henceforth, a rule is necessary to know: all supplies with wastewater intended to irrigation must be the subject, not only of a prior qualitative evaluation, but should encourage farmers for more rigors in the management and control of irrigation. If farmers can always use these waters for irrigation, it is their responsibility to take certain precautions. They must: (1) ensure that their soils present a sufficient permeability, (2) demonstrate competence in terms of irrigation (date, dose, frequency). Failing this, avoid growing plants sens itive to salt and to plant only “tolerant “. Otherwise, the competent authorities have the right to apply the”Precautionary Principe”