Abstract
The study was conducted on soils of Jazira area (North West Iraq) in the area between 200 and 400 mm isohytal lines to determine the relative distribution of non-erodible soil fractions NEF (with diameters> 0.84 mm) . Four samples of surface soil at a depth of (0-10 cm) and four subsurface soil at depth of (10-20 cm) distributed in the four directions were taken during August and September 2001. The samples were taken for dry sieving using sieves with diameter 0.25, 0.42, 0.84, 1, 2, 4, 6.4, 10 and 20 mm and the size distribution for the soil fractions was determined according to its erodibility. Some of the statistical parameters were established to find out the symmetry and dispersion characterization of soil fractions in the studied areas. The results revealed that all the studied areas were characterized by the increase of their contents with the non-erodible factions. Thus a resistance against the wind erosion was set as their content of the non-erodible fractions was higher by 50%. Also, the dry mean weight diameter have seen to be higher than the critical limit of non-erodible soil fractions diameter .
