Effects of Land Uses on Soil Quality of Shwan Sub-basin, Kirkuk Governorate, Northern Iraq

Abstract

اThirty-two soil samples were collected from the study area in October 2020 forgeochemical and pollutants investigation of Shwan Sub-basin soil. All soil sampleswere analysed for different geochemical analyses. The analysis results revealed thatthe pH values in soil samples ranged from 7.12 to 7.56 with a mean of 7.327.According to the pH values detected in the soil samples, the soil is classified as neutralsoil. The electrical conductivity ranged from 0.92 mmhos/cm to 7.8 mmhos/cm witha mean of 1.53 mmhos/cm. Thus, according to the detected electrical conductivityvalues, the soil was classified as non-saline to slightly saline. The organic matterranged from 1.14% to 1.45% with a mean value of 1.326 %, while total organic carbonranged from 0.66 % to 0.84 % with a mean value of 0.769 % which indicated the soilwas characterized by low organic content. The results of the geochemical analysisrevealed that the major and minor element mean concentrations were in the order Si>Ca> Al> Fe> Mg > K> Ti> Na> P> Mn> S> Cl> N. The average concentrations oftrace elements in soil samples followed the decreasing order Sr > Cr> Ba> Zr> Ni>V> Zn> Ta> Rb> Cu> Nb> Y> Pb> Co> Ga> Mo> As> Th> Br> Sn> I. Furthermore,the comparison between heavy metal concentrations in the soil of the study area andmetal concentrations in the world soil limit and Indirect Geochemical Backgroundrevealed an increase in metal concentrations of Cr, Ni, Zn, Co, As, Mo and Ta.Multivariate statistical analyses, such as Principal Component Analysis andAgglomerative Hierarchal Cluster Analysis, identified the potential sources ofpollutants in the soil. Most metals are from natural sources and some of them are fromanthropogenic sources mostly from agricultural activities mainly fertilizers use andthe waste of animals breeding on farms. Besides industrial activities such as depositsof pollutants from emissions of petroleum refineries located inside or close to thestudy area. In addition, building blocks and paint factories.