Classification and Distribution of Iraqi Soils

The work of soil survey and classification in Iraq was started before 1950. At this point in time, the number and type of soil units in Iraq are incomplete due to the lack of semi-detailed or detailed surveys covering all of Iraq. Nonsystematic work of soil survey has been the dominant type of work to date. Only 35% of Iraq is considered covered by a semi-detail survey work with 1:50 000 to 1:25 000 soil maps. There is no general soil map covering the whole country up to now,using soil Taxonomy or other system. The exploration work of Buringh in1960 using 1938 system, is the common work done on Iraqi soils.He recognized 18 great groups. So the need for detail soil survey to developing soil map at large scale is very necessary. In order to develop general soil map for Iraq following USDA soil Taxonomy, 300 pedons representing all expected Iraqi soils were collected from the previous works. The collected data were reclassified using the key of soil classification, 2012. Digitized soil map at 1:500000scale was developed. The results indicated the presence of five soil orders each one shows some variations with the common properties reflecting the effect of the dominant soil formation factors.The soil orders are arranged according to their dominance as following : Aridisols (62.2% ), Entisols( 16.2% ), Inceptisols ( 12.6) , Mollisols ( 3.8% ) and Vertisols (1.2% ),respectively. Twelve suborders belong to the dominant orders were recognized, with twenty five great groups.