Influence of the physiography location on characteristics of the sedimentary plain soils in al-Rifai District, Dhi Qar Province

Abstract EN

The study was conducted in Al-Rifai district, Dhi Qar province, which located between two latitude (29"44‾31° and 50" 44‾31°) and two longitude line (25" 06‾46° and 27"07‾46°) for the purpose of identifying and comparing spatial Variability in the properties of morphological and physiochemical soil within different physiologic units in the lower sedimentary plain in southern Iraq.

The soil samples were collected from three pedons represented by the traces of the river, river banks and river basin in three locations parallel to Al-Gharaf River which located within Al-Rifai district, Dhi Qar province during the period from November 2015 to April 2016.

The results of the physical analyzes showed that the predominant textures were sandy loam and loam, with a percentage of 33.34% for each of them, The general average for apparent density values for the pedons (1, 2, 3) amounted to (1.50, 1.48, 1.43 μg.m3), respectively.

The saturated Hydraulic Conductivity of all the pedons was classified on the basis of their general averages to the medium velocity class according to an assessment [20].

The results of the chemical analysis showed that the soil of the first pedon recorded the highest content of the organic matter amounted to (6.43 g.kg-1 ) followed by the second pedon amounted to (4.08 g.kg-1 ) while the soil of the third pedon recorded the lowest content amounted to (2.65 g.kg-1 ), all locations showed high content of calcium carbonate, with an average of (219 g.kg-1 ) within a range of (262-168 g.kg-1 ).

The results showed that the lowest Coefficient of Variance recorded for the traits of the pH, apparent density, porosity, and calcium carbonate levels amounted to (2.25, 6.04, 7.16, 12.41%), respectively, indicating a slight Covariance and state of homogeneous, while there were medium Covariance and state of heterogeneous for the traits represented by the sand, silt, clay, the salinity, and the Saturated Hydraulic Conductivity, where the Coefficient of Variance for these traits amounted to (31.39, 34.24, 35.30, 47.06, 54.30%), respectively.

The results of the field and laboratory studies showed that the soil of these locations belongs to the subgroup (Typic Torrifluvents).