Influence of Soil Physicochemical Properties and Farmers’ Pesticide Practices on Cypermethrin Residue Levels in Cowpea (Vigna unguiculata) in Keffi, Nigeria
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Abstract
This study assessed the influence of soil physicochemical properties and farmers’ pesticide use practices on cypermethrin residue levels in cowpea (Vigna unguiculata) cultivated in Keffi, Nasarawa State. A field experiment was conducted using five treatment plots. Soil samples were analyzed for physicochemical properties using a pH meter, Walkley-Black, Bray-1, and EDTA titration methods, while pesticide residues in cowpea were extracted by solvent extraction and analysed by Thin Layer Chromatography (TLC) for detection and UV-Vis spectroscopy for quantification. In addition, 45 cowpea farmers were surveyed to assess pesticide use behaviour, safety practices, and constraints. Soil analysis revealed a neutral pH (7.3), low cation exchange capacity (4.92 cmol/kg), moderate organic matter (4.47%), and a sandy loam texture dominated by sand (80%). These characteristics suggest low pesticide retention capacity and high mobility potential. Survey results indicated that 95.6% of farmers used pesticides, with cypermethrin being the most common (66.7%). Pesticide application was frequent, with 40% often exceeding recommended dosages (800mL/ha), and largely conducted using manual spraying methods (93.3%). Poor safety practices were observed, including low use of personal protective equipment (55.6%) and failure to observe pre-harvest intervals (60%). Cowpea samples were obtained from control, single-dose, recommended-dose, multiple-dose, and double-dose treatment plots and analyzed using TLC and spectrophotometric methods. Results showed no detectable residues in the control, single-dose, and recommended-dose groups, while high residue levels were recorded in the multiple-dose (2.42 ± 2.0 mg/kg) and double-dose (2.45 ± 1.0 mg/kg) groups, exceeding the WHO/FAO limit of 0.05 mg/kg. The study highlights potential food safety risks associated with pesticide misuse and emphasizes the need for improved farmer education, stricter regulatory enforcement, and promotion of sustainable pest management practices to reduce chemical contamination in food systems. The findings demonstrate that both environmental and human factors jointly influence cypermethrin residue levels in crops and calls for further studies and action.
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Copyright (c) 2026 Emmanuel, Eneojo Agada, Jamey Peters, Mairiga, Muhammad Bawa Yusuf, Ameh Benson Agi, Ene Etim Okon (Author)
This work is licensed under a Creative Commons Attribution 4.0 International License.
Emmanuel, Eneojo Agada, Joseph Sarwuan Tarka University, Makurdi, Benue state (Formerly FUAM), Nigeria.
Department of Biochemistry,
College of Biological Sciences.
Jamey Peters, Mairiga, Nasarawa State University, Keffi, P.M.B. 1022 Keffi, Nasarawa State Nigeria.
Department of Biochemistry and Molecular Biology,
Faculty of Natural and Applied Sciences.
Muhammad Bawa Yusuf, Nasarawa State University, Keffi, P.M.B. 1022 Keffi, Nasarawa State Nigeria.
Department of Biochemistry and Molecular Biology,
Faculty of Natural and Applied Sciences.
Ameh Benson Agi, University of Siegen, Germany.
Department of Chemistry,
College of Science.
Ene Etim Okon, Nasarawa State University, Keffi, P.M.B. 1022 Keffi, Nasarawa State Nigeria.
Department of Biochemistry and Molecular Biology,
Faculty of Natural and Applied Sciences.
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