Impact de la salinité de l'eau sur la qualité du sol et la betterave à sucre Beta vulgaris L.

Salinity poses several problems for plant growth and development by inducing physiological disfunctions. Species and varieties are however known to vary widely in their ability to tolerate salts. The use of salt tolerant species can contribute to a best valorization of salt soil. It is well known that Sugar beet is tolerant salts, and this can serve as an alternative culture in regions affected or abandonned because of excescive salinity. The aim of this study is the characterization of the quality of soil, growth and percentage of sugar of Beet cultivated in salty environment. A test in pot culure is effectued by imposing six levels (0,64 - 2,9 - 5,8 - 8,7 - 11,68 and 14,6 g/l) of NaCl. In this treatment, the soil used is wealth in organic matters (2,12%), and is characterized by a low initial salinity (CEs1:5 water soil extract 0,225 ds/m), a low alkalin pH (7,75) and a texture limono-sableuse. The variety of Sugar beet tested is Mribomagnapoly multigerm of type E, which was collected 170 days after the sowing. The study Shows that at concentration of NaCl higher than 8,76 g/l, the soil present an accumulation of solubles salts (salinization) and sodium (solarization). The growth was significantly affected at 11,68 g/l of NaCl concentration.The root seem to be less affected by water salinity than shoots: the dry weights reduction percentage of shoot and root is 48% and 39% respectively. On the other hand, salinity stress is responsible for Sodium accumulation and Potassium deficiency in root. The Sugar beet is tolerant to salinity in terms of yield and survival, but the sucrose content is significantly reduced under saline condition.La salinité des eaux et des sols limite la productivité et l'extension des cultures sensibles. La présente étude a pour objectif de caractériser la qualité du sol, la croissance et le taux de sucre de la betterave à sucre cultivée dans un milieu salin. Des cultures de betteraves à sucre irriguées par des eaux contenant 0,64 à 14,6 g/l de NaCl montrent qu'à des concentrations qui dépassent 8,76 g/l le sol présente une accumulation des sels solubles (salinisation) et de sodium (sodisation). La croissance des plants est significativement affectée suite à l'irrigation par des eaux à une concentration de 11,68 g/l en NaCl. La betterave à sucre a montré une résistance à la salinité, et si des doses modérées en NaCl se sont montrées favorables, celle-ci voit sa richesse saccharine diminuer fortement sous stress salin