ones are the most dominant in the new reclaimed areas in Egypt. The main production constraints of this type  of  soil  are  low in organic carbon,  porosity,  stable aggregates, water retention capacity, and biological  activities. Agriculture soil should have not only a good structure but also a good structure which can persist for a long time (e.g., a structure of high quality and stability). Soil aggregates are structural units of soil, which create complex pore systems controlling gas and water storage and fluxes in soil. Formation and stability of natural soil aggregates are affected by dozens of different factors and their individual effects are hardly distinguishable. Therefore, to observe more clear the mechanisms governing their water and mechanical stability, it was found necessary to  study soil  aggregates. In that sence, some studies showed encouraging findings of increasing soil stable aggregates due to using different soil conditioners. The objective of this work is to assess some extracellular polysaccharides biopolymers, i.e., Dextran, Alginate, Xanthan, Pullulan, and Curdlan, which were produced in our laboratory under the most suitable production conditions, to test their effects on the physical proprerties of soil taken   from Toshka region at Aswan Governorate of Egypt. Data showed that soil porosity and MWD_wet values have significant differences between all treatments and control under un-leaching processes. On the Other hand, in leaching processes, significant differences between all treatments and control were observed except in some treatments that using lower ratios of Pullulan and Curdlan biopolymers (i. e. 0.4, 0.6 and 0.8%).
Generally, the beneficial order of enhancement of aggregate stability was obtained with Dextran, followed by Alginate, Xanthan, Pullulan, and Curdlan.