Assessment of Soil Physical Quality and Organic Matter Variability Using GIS Techniques in Ghammas District, Iraq

• Abeer Karim Awan1* and Mustafa Qais Hamid2

  Author

Soil physical quality is an important indicator to provide insights on soil functioning and has implications for agricultural management, especially in semi-arid environments where arable land degradation and low productivity are two major problems. Abstract This study was conducted to assess the variability of selected indicators of soil physical quality and organic matter content under cultivated land and uncultivated land at Ghammas District, Al-Qadisiyah Governorate, Central Iraq using Geographic Information System (GIS) methods. Based on the prominent land-use systems within the study area, soil sampling sites were chosen near 30 cultivated and 10 uncultivated (natural), for a total of 40 analyses. Bulk density, particle density, total porosity, and organic matter analysis were performed in soil samples. The spatial analysis and the thematic maps were performed using ArcGIS Desktop and the Kriging method to analyze the properties investigated. The results showed significant spatial variability in some indicators of soil physical quality throughout the study area. The bulk density varied between 1.22 and 1.59 Mg m-3, particle density among 2.61 to 2.69 Mg m-3 Total porosity between 40.31% and54.43% with clear inverse correlation to the bulk density. The content of organic matter was variable and between 0.052% – 1.707%, with an average of the mean value being 0.993%. Compared with several uncultivated sites, characterized by higher bulk density and lower porosity and relatively greater organic matter contents values of soil structural conditions improved by agricultural management (tillage practices) and inputs: crop residues. The combination of laboratory measures and spatial analysis using GIS resulted in a good evaluation of the variability in organic matter and physical quality of soil. This data contributes to find more detailed information for site-specific soil management, land-use, and sustainable agricultural development in semi-arid areas. the study suggests to rely on strategies that increase organic matter inputs by means of residue retention and/or additional organic amendments, as a means to improve soil structure in order to sustain longterm productivity.

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