Soil alterations due to flooding: An examination of morphological and physical properties of soils in imo and Anambra states, Nigeria

The morphological and physical properties of soils largely determine their behaviour, productivity and resilience to flooding in low-lying ecosystems. Soil samples were collected from six high-risk flood locations in Imo and Anambra States at 0–15 cm, 15–30 cm and 30–45 cm depths, with two control samples from elevated non-flooded towns. Results showed significant differences in colour, structure, drainage and texture reflecting local hydrological regimes. Floodplain sites such as Akili-Ozizor, Atani and Odekpe exhibited olive to grey gleyic hues, poor drainage and medium subangular blocky structures, features typical of prolonged saturation and iron reduction. In contrast, the upland control at Ihiala displayed reddish, well-drained profiles with friable consistencies. Hydromorphic patterns were also observed at Abacheke, Ekeugba and Mmahu, where dark greyish colours and fine roots indicated fluctuating water tables and limited pedogenic development. Particle-size analysis revealed predominantly sandy clay to clay loam textures, with clay enrichment up to 410 g kg⁻¹ at Abacheke and Amafor linked to sedimentation during floods. Sand-to-clay ratios, bulk density (1.27–1.44 Mg m⁻³), total porosity (45–52%) and gravimetric moisture (10–25%) varied widely, reflecting microtopographic influences on drainage, aeration and compaction. High porosity and moisture in Amafor and Ihiala favoured water retention, whereas higher bulk density and lower porosity in Akili-Ozizor suggested greater susceptibility to waterlogging and restricted root growth. These findings underscore the strong influence of flooding, sediment dynamics and soil physical properties on land use and floodplain agriculture, where texture, bulk density and porosity shape crop suitability, nutrient cycling and microbial activity under recurrent inundation.