Monitoring of Soil Salinization under Different Irrigation Water Amounts: Case of Tomato Crop Drip Irrigated within Kalaat El Andalous Irrigated District (North-East of Tunisia)

This work was conducted in a tomato plot, within the irrigated district of Kalaat El Andalous, of 0.3 ha and managed with drip irrigation system. The main objectives of this study are to assess and to monitor the evolution of soil salinization during an irrigation season under different water irrigation supplies generated by emitters delivering flow rates of 1.5 l/h, 2 l/h, 2.5 l/h and 3 l/h respectively in order to determine one salts soil pattern representative to the whole plot. Throughout the irrigation season, flow water variation didn’t exceed +/-3% and the average uniformity coefficient was about 71%. Such heterogeneous water distribution has led either to an excessive water amounts either to a deficient water amountscompared to theoretical irrigation requirements estimated at 890.5 mm. In terms of soil salinity, the heterogeneity of water distribution has resulted, either in salts leaching either in salts accumulation in the soil. Indeed, starting with an initial stock of salts of 5.23 dS/m in the layer (0-80 cm), an excess supply of water of about 6% was resulting in a decrease of salts stock of about 5.5 %. On the other hand, deficit supplies of water of 12.3%, 29.5% and 47.7% as recorded under emitters debiting 2.5 l/h, 2 l/h and 1.5 l/h respectively have resulted in an increase of salts stocks of 40.9 % 53.3 % and 75.4 % respectively. The average stock of salts in the layer (0-80 cm) was about 7.58 dS/m.