Shallow Water Table-induced Soil Degradation of a Lacustrine Cultivated Soil

Land degradation is a world challenge for sustainable agricultural production and food security. This study aimed at evaluating the impact of shallow water table conditions on the soil degradation rate of Abis Experimental Research Station, Alexandria governorate, Egypt. Soil salinization, sodication and water logging conditions were assessed through collecting surface (0-30 cm) and subsurface (30-60 cm) soil samples and water table samples in 2016. The data obtained were compared with a previous survey study in 2007 and the salinization, sodication and water logging index rates were calculated. Generally, mean values of EC (dS m-1) and ESP (%) increased and water table depth decreased with high spatial variability and more areas suffered from salinity and sodicity in 2016 compared to 2007. Within a period of nine years, 46% and 47% of the cropland area were converted from “non to slightly saline” to “moderately to highly saline” soil in the surface and subsurface layers, respectively. About 45% and 46% of the area were deteriorated and turned into sodic soils in the surface and subsurface layers, respectively. The water-table intruded much more to the soil surface where 95% of the cropland area had water-table depth of 50-100 cm. The salinization rate index was < 2 dS m-1/year (Non to slight) for the all observations. 35% of the area showed moderate sodication rate (1-2 increase in ESP/year) and only 4% with high sodication rate (2-3 increase in ESP/year). A moderate (1-3 cm decrease/year) and high (3-5 cm decrease/year) water logging rates were observed in 46% and 28% of the area, respectively, which were mostly found in the Eastern part of Abis farm.