Changes in the granulometric composition of Zarafshan river soils under irrigation and comparative analysis

According to the granulometric composition of all soil types (typical, light gray, gray-meadow and meadow-alluvial) located on terraces I - II III Zarafshan oasis, it is mainly medium heavy sand, physical clay (<0.01 mm) large dust (0.05 – 0.01 mm), (0.01 0.005 fine (0.005 0.001 silt particles due irrigation for many years reduced sand increased amount in layers . It explained by erosion feldspar, mica-like substances particles, increase upper as a result irrigation, fact that certain parts are washed lower soil.