Physicochemical Characteristics of Gully Impacted Soils in Southeast Nigeria

Abstract

Gully erosion is a critical environmental concern in Southeast Nigeria, causing extensive land degradation, 
loss of arable soil, and disruption of socio-economic activities. This study investigates the physicochemical 
characteristics of gully-impacted soils across three states—Imo, Abia, and Anambra—representing the 
Southeast geopolitical zone, with soils from Rivers State serving as a control. The research aimed to identify 
key soil properties that influence erosion susceptibility and to inform effective mitigation strategies. Soil 
samples were analyzed for pH, bulk density, porosity, moisture content, organic carbon, organic matter, 
cation exchange capacity (CEC), and exchangeable bases. Results reveal that most gully-affected soils were 
acidic (pH 0.62–6.08), compared to the near-neutral control (pH 7.15), indicating a potential role of acidity 
in soil structure breakdown. Bulk densities of affected soils (0.853–1.479 g/cm³) were lower than the control 
(1.624 g/cm³), while porosity values (44.32–67.82%) were significantly higher, suggesting increased pore 
space that may weaken soil cohesion and promote erosion. Organic carbon (0.09–3.02%) and organic matter 
(0.10–5.21%) levels were variable, with several samples falling below control levels, potentially limiting 
structural stability. Moisture content ranged widely (0.22–11.26%), indicating inconsistent water retention 
capacity. Exchangeable calcium and magnesium were generally lower in the affected soils, while sodium 
was higher—conditions unfavorable to aggregate stability. Most samples also exhibited reduced CEC 
compared to the control (29.78 meq/100g), indicating lower nutrient-holding capacity. Texturally, soils 
were predominantly sandy and loamy sand, with minimal clay content, further exacerbating erodibility.    
The study concludes that the interplay of low pH, high porosity, low nutrient retention, and poor structural 
integrity contribute significantly to gully formation. Therefore, integrated soil management practice is 
recommended, such as liming, organic amendments, and targeted fertilization—to enhance soil stability 
and combat erosion in the region.