Six profiles, clay texture, were selected. Profiles 1 and 2 represent soil irrigated with good quality water, while profiles 3,4 refer to soil irrigated partially with lower quality of irrigation water. The last two profiles 5,6 irrigated with the lowest water quality. Soil samples comprise all soil profiles for different required analysis and also water samples were collected from different locations related to soil profiles. The chief purpose of the study is to inquire and evaluate the effect of irrigation water quality and its affect on soil physical and chemical properties.
Irrigation water quality was deteriorated as it becomes closer to the coast of Mediterranean sea. As a consequence, profiles 5 and 6 have the highest values of soil salinity and exchangeable cations as a sequence of using the lowest quality of irrigation water. Water salinity of irrigation resources for profiles 5,6 were 0.87 dS/m and 0.83 dS/m, which reflected in salt content of profiles 5 and 6 to be 1.6 and 0.99 dS/m, respectively. ESP has also the highest values in profiles 5 and 6, which reached 23.4 % for each. On the contrary, profile 2 has the highest value of exchangeable calcium (27.6 meq/100g soil). Total water stable aggregates (> 0.25 mm ) has a high negative correlation with salinity of irrigation water and ESP. The correlation was found to be -0.683** for ECiw and –0.547** for ESP. Structure Coefficient revealed a similar negative correlations to be (-0.544**), (-0.411*) and (-0.502*) for ECiw, SAR and soluble Sodium of irrigation water, respectively. On the contrary ECaP has a positive correlation with each of optimum size of aggregates to be (0.458*) and water stable aggregates (1-0.5mm) to be (0.543*). ECiw as well as soluble magnesium and soluble Sodium has a negative effect on soil bulk density, which increased as the before mentioned salts increased.
It is to conclude that low quality of irrigation water affect negatively the most of structure parameters, i.e. aggregates criteria and other soil physical properties. Therefore, sustainable plane for soil conservation especially at North Nile Delta, have to perform to maintain its potentiality and productivity.