Diagnosis of the waterlogging and the soil salinity status in irrigated areas after several decades of irrigation: The case of Henchir Tobias in lower valley of Mejerda river (Tunisia)
Pages : 1307-1314Download PDF
In semi-arid and arid countries, irrigation is an important requirement for crop production. The aim of this study was to characterize the current status and to develop statistical regression models and map spatial variations in soil salinity in the irrigated perimeter of Henchir Tobias. During the two control campaigns of autumn 2014 and spring 2015, this irrigated perimeter was characterized by higher salinity in the surface horizons. It remains highest in the underlying horizons. The spatial distribution of soil salinity (Electric Conductivity of paste extract: ECe) shows that it is generally higher in the eastern and northeastern parts of the irrigated perimeter, especially in autumn 2014. The underground water is more salty in the center and north-eastern part of the perimeter. High values of electrical conductivity of the ground water (ECâ„12 mS/cm) were noted in autumn 2014. A significant linear and positive correlation (r = 0.477) between underground water salinity and underground water level were established for the spring campaign of 2015. However, there is not a significant correlation between the underground water level and soil salinity, but with correlation coefficients approaching the significance threshold. There is a relationship between the underground water salinity and soil salinity for the autumn campaign of 2014. There is also a positive correlation (r = 0.77) between the underground water salinity and the soil salinity only for the upper horizon (0-20 cm) in spring 2015. The investigation of the interaction between soil characteristics and plant production has shown that there is a significant but negative correlation between the average of soil salinity and yield of artichoke (Cynara scolymus L.). However, underground water levels and salinity have strong negative effect on the yield of artichoke crops.
Keywords:Â Waterlogging, salinization, soils, piezometers, yield, Tunisia