Characterization and Classification of Soils in Al-Muwafaqiyah and Al-Dujaili Areas within Al-Kut District, Wasit Governorate, and Evaluation of Their Agricultural Suitability

Abstract

The aim of this study was to characterize and taxonomically classify two agricultural soil sites, Al-Muwafaqiyah (K1) and Al-Dujaili (K2), of the Tigris alluvial plain of Wasit Governorate in central Iraq, each represented by three field replicates, and to evaluate their agricultural suitability. This site-level characterization is intended as a preliminary contribution rather than a comprehensive regional soil survey. Both locations are predominantly irrigated by surface water from the Tigris River and associated irrigation canals, not by groundwater wells. The surface soil samples (0-30 cm) were tested for soil reaction, electrical conductivity, Cation Exchange Capacity, organic matter, calcium carbonate, soluble ions, available N, P, and K, particle-size distribution, sodium adsorption ratio, exchangeable sodium percentage, and suitability indicators. Soils were slightly alkaline (pH 7.29) and moderately calcareous (CaCO3 21.49%), and lower than the monitoring threshold for salinity (mean ECe 3.65 dS m-1) but not severely saline, and low in organic matter (mean 6.38 g kg-1). The ESP averaged 17.30%, which is regarded as the main management constraint, with sodicity being the predominant issue. Texture varied in local deposits within the alluvial plain, becoming silt-dominated in K1 and a clay-loam in K2. The soils at both Al-Muwafaqiyah and Al-Dujaili were classified as Typic Torrifluvents (USDA Soil Taxonomy: order Entisols, suborder Fluvents) based on representative pedons at each site through morphological observations and laboratory analyses. The field morphology, recent alluvial parent material of the Tigris, and the physicochemical features of both representative soil profiles support this classification. Data from descriptive statistical analysis indicated low to moderate differences between sites for most of the soil properties used for this study, and high variability within the sites for available N. Agricultural suitability was determined as moderately suitable (S2), which was primarily limited by sodicity, low organic matter, and moderate nutrient-retention capacity. As a preliminary, site-level characterization, the results of this study indicate that combining soil chemistry, pedon morphology, texture classification, descriptive statistics, and taxonomic interpretation provides a more informative basis for the management of alluvial agricultural soils in the Al-Kut District than any single indicator alone, while broader, more intensively replicated survey work is still needed to support a comprehensive regional management framework.

DOI: https://doi.org/10.54633/2333-025-059-019