IMPACTS DES PARAMETRES PHYSICO CHIMIQUES SUR LA PRODUCTION DE LA SPIRULINE ENDEMIQUE AU TCHAD (SPIRULINA PLATENSIS (GOMONT) GEITLER, OSCILLATORIACEAE) DANS LE WADI DARTOMOSSI (PROVINCE DU LAC)

Spirulina (Spirulina platensis) is one of the most widely used algae because of its protein content. In Chad, the women of the Kanembou community traditionally exploit the spirulina algae that grew spontaneously there. In Artomossi, it is in a brackish water wadi (pond) where this spirulina naturally grows. It is the fluctuation of the physico-chemical parameters of this brackish water and the socio-cultural constraints that do not favour this production in order to cover the quantity and quality of consumer demand. The physicochemical parameters of this water are studied in order to assess their impact on the production of this spirulina. Twenty-three women producers, belonging to six groups, were surveyed. Regardless of the season during the year and the variability of the physicochemical parameters of this brackish water, the production of Artomossi spirulina is optimal early in the morning before sunrise. Depending on the season, the small harvest period extends from April to September and the great harvest period extends from October to March. When the pH 9.5 and the daytime temperature  18°C, the production of Artomossi spirulina is optimal. These values show that this living environment is alkaline-like. The average artisanal production is 3.75 kg/day/producer during the small harvest period and 6.6 kg/day/producer during the major harvest period i.e. 10.35 kg/year/producer of dry spirulina. Such results are a prerequisite for support for this sector in Chad and sustainable management of this resource.