Effect of Separate Clayey Patches in Loamy Sand Soil on Both of Solute Transport and Salinity Distributioin

Soil permeability and soil salinity are considered the most important elements affecting agriculture in arid areas. To analyze and visualize solute transport and soil salinity distribution mechanisms, dye tracer and an electromagnetic device (W.E.T Probe) were used. The purpose of this study is to investigate the effect of separate clayey patches (spots) exist in loamy sand soil on both of soil permeability and salinity distribution. Two sites at Sahl El-Tina area in El-Salam Canal project service area, eastern of Suez Canal, Egypt were chosen. The soil type at the first site is loamy sand with separate clayey spots while the type is sandy soil at the second. Two experimental plots, one plot in each sit (1mx1m), were prepared for the infiltration of dye by leveling the surface. Each plot was irrigated with solution containing dye tracer for three days. On the day following the last day of irrigation, a trench was dug and ten centimeter thick vertical slices were excavated and photographed. Soil bulk salinity measurements through a grid of 1 meter width and 0.5 meter depth and 10 cm interval were taken. The dye photographs showed that solute transport is very poor at the site contained clayey spots. Small preferential flow is obvious within the same site. When matching the photos of the sections with the corresponding contour maps of soil salinity, it was found that points of high level of salinity coincides well with points of clayey spots. In general, the existence of clayey spots within loamy sand soil decreases solute transport. Furthermore, points of high salinity through the soil which coincide with these spots were not affected by continuous washing during irrigation. These high salinity patches will have its effect on plant growth.