Journal of Natural Science Research and Review (JNSRR)

Influence of Repeated Agrochemical Inputs on Nutrient Availability and Heavy Metal Status of Lowland Soils of Ifite-Ogwari Anambra State Nigeria

Okafor, M. J., Nnabuihe, E. C., Apalowo, O. A., Onunwa, A. O., Anene, C. K., Ernest, C. I., Nwaiwu, C. J., Nwankwo, J. E., Obidiebube, E. A., Uko, I., Anarah, S. E.

31 August 2025 · Vol. 1, Issue 2, pp. 33-38

DOI: 10.65150/EP-jnsrr/V1E2/2025-A008

Abstract

This study evaluated the influence of repeated agrochemical inputs on nutrient availability and heavy metal status of lowland soils in Ifite-Ogwari, Anambra State. Composite soil samples were collected from agrochemical-treated fields (AGI) and adjacent fallow soils (control) at two depths (0–15 cm and 15–30 cm). Standard laboratory analyses were conducted to determine texture, bulk density, pH, organic carbon (OC), total nitrogen (TN), exchangeable bases, effective cation exchange capacity (ECEC), available phosphorus (Av.P), and concentrations of arsenic (As) and lead (Pb). Results showed significant reductions (p ≤ 0.05) in OC, TN, Ca²⁺, and Av.P under AGI soils compared with controls, indicating fertility depletion. Soil pH remained acidic across sites, but AGI soils recorded slightly higher values. Heavy metals exhibited contrasting trends; arsenic (As) was significantly higher in AGI soils at 15 – 30 cm depth, while Pb concentrations showed no significant difference (p ≤ 0.05) between AGI and control soils nor across depths. Correlation analysis revealed that arsenic (As) was strongly correlated with soil texture (silt, clay) and pH, whereas Pb correlated with exchangeable bases (Na⁺, Mg²⁺, Ca²⁺). Although As and Pb levels remained below international safety limits, the observed build-up under continuous inputs highlights the risk of long-term accumulation. The findings demonstrate that repeated agrochemical use compromises soil fertility and promotes gradual heavy metal enrichment, underscoring the need for integrated soil fertility management and reduced dependence on chemical inputs in lowland rice systems.

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Okafor, M. J., Nnabuihe, E. C., Apalowo, O. A., Onunwa, A. O., Anene, C. K., Ernest, C. I., Nwaiwu, C. J., Nwankwo, J. E., Obidiebube, E. A., Uko, I., Anarah, & S. E. (2025). Influence of Repeated Agrochemical Inputs on Nutrient Availability and Heavy Metal Status of Lowland Soils of Ifite-Ogwari Anambra State Nigeria. Journal of Natural Science Research and Review, 1(2), 33-38. https://doi.org/10.65150/EP-jnsrr/V1E2/2025-A008

@article{Okafor2025,
  title   = {Influence of Repeated Agrochemical Inputs on Nutrient Availability and Heavy Metal Status of Lowland Soils of Ifite-Ogwari Anambra State Nigeria},
  author  = {Okafor and M. J. and Nnabuihe and E. C. and Apalowo and O. A. and Onunwa and A. O. and Anene and C. K. and Ernest and C. I. and Nwaiwu and C. J. and Nwankwo and J. E. and Obidiebube and E. A. and Uko and I. and Anarah and S. E.},
  journal = {Journal of Natural Science Research and Review},
  year    = {2025},
  volume  = {1},
  number  = {2},
  pages   = {33-38},
  doi     = {10.65150/EP-jnsrr/V1E2/2025-A008},
  url     = {https://doi.org/10.65150/EP-jnsrr/V1E2/2025-A008}
}

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