- *Nnabuihe, E. C 1, Okafor, M.J 1, Nwosu, T.V 1, Ugochukwu, G.U 4,Onunwa, A.O 1, Apalowo, O.A 3, Ibigweh, M. N 1, Nwaiwu, C. J 1,Anarah, S. E 5, Steve-Obi, C. E 1, Madueke, C.O 2
- Nnamdi Azikiwe University Awka Anambra state Nigeria.
- DOI: 10.5281/zenodo.17009297
Sustainable
agricultural production in southeastern Nigeria is hindered by declining soil
fertility, where continuous cultivation and poor management have intensified nutrient
depletion. This study evaluated soil fertility under arable, pasture, and
forest land uses at the Ifite Ogwari Campus of Nnamdi Azikiwe University
(06°60′14″N, 06°95′02″E) to identify key constraints and propose management
options. A transect method was employed, and three representative soil profiles
were dug across the land uses, from which twelve samples were collected along
genetic horizons and analyzed for physical and chemical properties. Results
revealed that soils were predominantly sandy loam (SL) to loam (L) in arable
and pasture lands, and sandy loam (SL) to loamy sand (LS) in forest land use.
Bulk density (1.30-1.55 Mg m⁻³) and porosity (41.5-50.9%) suggested favorable
structure, but wide spatial variability was recorded for organic carbon (OC),
total nitrogen (TN), and clay (CV >30%). The soils were strongly acidic (pH
4.9-5.6), with low organic carbon (<4.5 g kg⁻¹), total nitrogen (<0.4%),
and critically deficient available phosphorus (<3 mg kg⁻¹). Exchangeable
Ca²⁺ and Mg²⁺ were also below critical levels. Correlation heatmaps showed
strong positive associations between OC and TN (r ≈ 0.99) and between Ca2+ and
total exchangeable bases (r ≈ 0.98), with BD and TP inversely related (r ≈
–0.99). These findings identify soil acidity, organic matter decline, and
phosphorus deficiency as the dominant fertility constraints. Recommended
strategies include integrated use of organic amendments, liming, and phosphorus
fertilization to restore soil productivity and support sustainable intensification
in southeastern Nigeria.
