الخلاصة

Abstract: Ten pedons were selected within three zones northern Iraq, represent a high mean annual rainfall to study parent material uniformity in some soils northern Iraq by using non clay size distribution and weathering resistant mineral size distribution. The results showed sand fractions (very coarse sand , coarse , medium , fine , very fine sand) and abundant arrangement take this order .very fine sand >fine sand>medium>coarse>very coarse sand , accept pedon 10 located in sarsang were medium sand was greater than fine and very fine sand . The used parameters is 1.very fine sand (0.1-0.05)/total sand 2. fine sand (0.1- 0.25)/total sand 3. the sum fine and very fine sand /total sand. The results showed parameter 2 was the best ratio and gave us vertical uniform distribution with uniform value ranged (0.20-0.39) in all studied soils . Results indicate quartz percent was uniform vertical distribution within same pedon horizons and no significant differences between different pedons and the mineral percent was (29.59-43.36) and garnet (1.03-4.61) variance coefficient resultsfor used minerals content indivate existence uniformity for parent material and was(2.22-11.1) for quartz and (8.65-15.32) for garnet and this results confirm existence of uniformity state in parent material in studied soils.