COMPETENCY OF SOME SOIL AMENDMENTS USED FOR IMPROVEMENT OF EXTREME SALINITY OF SAHL‚ EL-TINA SOIL (NORTH-SINAI)

A field experiment was conducted on a clay saline soil of Sahl El-Tina area, North Sinai, Egypt to evaluate the efficiency of some soil amendments i.e., Gypsum (G), Sugar Lime (S.L.), Cement Klin dust By-Pass (B.P.), Mixture (M₁) of (B.P., Vinasse "V" and H₂SO₄ "2:1 A: water") and Mixture (M₂) of (S.L., B.P., Vinasse "V" and H₂SO₄ "conc.") on some characteristics of the studied soil. EC (108 dS m^-1), pH (8.60) and ESP (32%) of the surface layer "0-20cm". Intermittent leaching technique was adopted using El-Salam canal water in experiment.
    The results showed that the chemical properties of the studied soil were clearly improved due to amendments addition. The common parameters of saline sodic soil i.e., EC, pH and ESP were clearly improved. The superior improvement of these parameters was resulted with M₂ treatment. Leaching is the only effective way to decrease the excessive salts from the root zone. Data showed that EC_e was 108 and 101 dSm^-1before leaching and decreased to reach about of (22 and 33 dSm^-1) by decreasing rate (80and 67%) at the end of leaching for surface and subsurface layers, respectively. The amendment can be arranged, due to its effect on soil sodicity, in the order of: M₂> M₁>G>S.L.> B.P. The lowest mean values of ESP were recorded under M₂. It was 19.20 and 24.21% with relative decrease was 40and 35% as compared to the initial ESP of soil.
Application of different amendments significantly improved the studied physical properties of the tested soil. Data showed that leaching only (L) led to increase quickly drainable pores (QDP) by (47.34%) while, decrease fine capillary pores (FCP) by (5.57%) compared to initial soil. The application of soil amendments added as alone or in mixtures encouraged the formation of quickly drainable pore and water holding pores. Soil amendments are more effective in surface than subsurface layers. At average basis the QDP, and WHP increased by (50.15%), (21.07%) respectively and fine capillary pores decreased by (14.63%) compared to the (L) treatment. Mixture of amendment M₂ was the superior to all other amendments in reducing FCP in surface layers. All amendments reduced soil B.D and increased Ks. However, M₂ was more pronounced especially in the surface layer. The differences were statistically significant. The best treatment, in the regarded, was also M₂.Thus, application of different amendments in mixtures with intermittent leaching technique may be a good step in the strategy to reclaim the clay soils, suffering from extreme salinity. Whereas, this technique help soils to get rid a huge amount of their salinity.