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Journals / Frontiers in Life Sciences and Related Technologies / 2026 / Volume: 7

Beyond broad-spectrum fertilization: genotype-specific responses of cowpea to integrated bio-inorganic amendments in Edo State, Nigeria

Chetachi Anne Ngwoke(Benson Idahosa University, Benin City, Edo State, Nigeria)0009-0000-3312-5879
Solomon Esharegoma Omonigho(University of Benin)0000-0001-7557-1789
Sunday Aghafekokhian Ogedegbe(University of Benin)0000-0002-4981-7412
Pages
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Publication Date
2026-09-20
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

These findings indicate that broad-spectrum fertilization is suboptimal.

📌 3 Key Takeaways

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Objective & Hypothesis:This study evaluated the in vitro plant growth-promoting traits of isolated rhizobacteria and their in vivo synergistic effects when co-applied with inorganic fertilizers on the yield of three cowpea varieties (IT90K-82-2, IT89KD-391, and IT99K-593-1-1).
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Key Findings & Data:Molecular characterization via 16S rRNA sequencing identified the biofertilizer isolates as Enterobacter hormaechei, Enterobacter cloacae, Alcaligenes sp., and Clostridium beijerinckii.
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Conclusion & Impact:These findings indicate that broad-spectrum fertilization is suboptimal.
🔬Design:Research Article
📍Scope:Comprehensive Sample
⚙️Variables:16S rRNA · biofertilizers · Enterobacter cloacae

Abstract

This study evaluated the in vitro plant growth-promoting traits of isolated rhizobacteria and their in vivo synergistic effects when co-applied with inorganic fertilizers on the yield of three cowpea varieties (IT90K-82-2, IT89KD-391, and IT99K-593-1-1). Molecular characterization via 16S rRNA sequencing identified the biofertilizer isolates as Enterobacter hormaechei, Enterobacter cloacae, Alcaligenes sp., and Clostridium beijerinckii. In vitro biochemical assays revealed that E. cloacae exhibited the highest phosphate solubilization efficiency (239.0 µg/mL) and Indole-3-acetic acid (IAA) production (44.0 µg/mL), coupled with a significant reduction in medium pH. Field evaluations demonstrated that integrated nutrient management (INM) significantly (p < 0.05) enhanced nutrient mobilization, with E. cloacae and inorganic fertilizer combination (B2I2) achieving the maximum depletion of available soil phosphorus post-harvest. Consequently, the combined treatments overwhelmingly outperformed unamended controls across all crop yield parameters. Notably, the study revealed strong genotype-by-treatment interactions. Treatment C2B2I1 gave the greatest increase in plant height (29.56 cm), number of branches (6.90), and leaf area (8.54 cm2), while treatment C1B3I1 gave the highest number of leaves (23.23). Maximum increase in stem girth (3.39 cm) was achieved by treating with C2B2I2. For the Yield Parameters, Treatment C2B2I1 gave the maximum Pods per plant (PPP) (7.00), the highest Number of seeds per pod (NSPP) (7.67), the highest Number of Nodules per plant (NPP) (7.67), and the longest root length (18.80 cm). This study revealed that biofertilizer isolate B2 (E. cloacae) was most effective in enhancing cowpea growth and yield. Combinations with biofertilizer isolate B4 (C. beijerinckii) and inorganic fertilizer 2 should be avoided unless improved formulations are available. Variety C2 was identified as a high-performing genotype under integrated nutrient management. These findings indicate that broad-spectrum fertilization is suboptimal. Instead, the precise, genotype-specific integration of highly efficient microbial inoculants with inorganic fertilizers provides a highly sustainable and effective strategy for maximizing cowpea yield in nutrient-depleted soils.

Özet

This study evaluated the in vitro plant growth-promoting traits of isolated rhizobacteria and their in vivo synergistic effects when co-applied with inorganic fertilizers on the yield of three cowpea varieties (IT90K-82-2, IT89KD-391, and IT99K-593-1-1). Molecular characterization via 16S rRNA sequencing identified the biofertilizer isolates as Enterobacter hormaechei, Enterobacter cloacae, Alcaligenes sp., and Clostridium beijerinckii. In vitro biochemical assays revealed that E. cloacae exhibited the highest phosphate solubilization efficiency (239.0 µg/mL) and Indole-3-acetic acid (IAA) production (44.0 µg/mL), coupled with a significant reduction in medium pH. Field evaluations demonstrated that integrated nutrient management (INM) significantly (p < 0.05) enhanced nutrient mobilization, with E. cloacae and inorganic fertilizer combination (B2I2) achieving the maximum depletion of available soil phosphorus post-harvest. Consequently, the combined treatments overwhelmingly outperformed unamended controls across all crop yield parameters. Notably, the study revealed strong genotype-by-treatment interactions. Treatment C2B2I1 gave the greatest increase in plant height (29.56 cm), number of branches (6.90), and leaf area (8.54 cm2), while treatment C1B3I1 gave the highest number of leaves (23.23). Maximum increase in stem girth (3.39 cm) was achieved by treating with C2B2I2. For the Yield Parameters, Treatment C2B2I1 gave the maximum Pods per plant (PPP) (7.00), the highest Number of seeds per pod (NSPP) (7.67), the highest Number of Nodules per plant (NPP) (7.67), and the longest root length (18.80 cm). This study revealed that biofertilizer isolate B2 (E. cloacae) was most effective in enhancing cowpea growth and yield. Combinations with biofertilizer isolate B4 (C. beijerinckii) and inorganic fertilizer 2 should be avoided unless improved formulations are available. Variety C2 was identified as a high-performing genotype under integrated nutrient management. These findings indicate that broad-spectrum fertilization is suboptimal. Instead, the precise, genotype-specific integration of highly efficient microbial inoculants with inorganic fertilizers provides a highly sustainable and effective strategy for maximizing cowpea yield in nutrient-depleted soils.

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Cite This Article

Ngwoke, C. A., Omonigho, S. E., Ogedegbe, S. A. (2026). Beyond broad-spectrum fertilization: genotype-specific responses of cowpea to integrated bio-inorganic amendments in Edo State, Nigeria. Frontiers in Life Sciences and Related Technologies, Volume: 7. https://doi.org/10.51753/flsrt.1911870

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References (37)

  1. Abebe, B. K., & Alemayehu, M. Y. (2026). Phosphorus fraction transformation and soil acidity mitigation through integration of water hyacinth biochar with organic and synthetic phosphorus sources in acidic soil. Frontiers in Environmental Science, 14, Article 1742046. https://doi.org/10.3389/fenvs.2025.1742046.
  2. Adebayo, A. A. (2020a). Geospatial analysis of urban growth in Benin City, Nigeria. Journal of Urban and Regional Planning, 11(1), 1-12.
  3. Adebayo, O. A. (2020b). Soil Microclimate Conditions and Legume Canopy Development in Southern Nigeria. Academic Press, Benin City, Nigeria. 112-125.
  4. Aliyu, A., Madukwe, D. K., Meka, I. N., & Ojeniyi, K. A. (2026). Effect of triple superphosphate (TSP) fertilizer rates on cowpea growth and yield under irrigation: A case of lowland area, Sokoto state, Nigeria. Journal of Current Opinion in Crop Science, 7(1), 20-33.
  5. Bolan, N. S., Kirkham, M. B., & Tate, R. L. (2022). Long-term effects of fertilizers on soil carbon and nitrogen. Soil Science Society of America Journal, 86(2), 257-265.
  6. Boukar, O., Belko, N., Chamarthi, S., Togola, A., Batieno, J., Owusu, E., Haruna, M., Diallo, S., Umar, L., & Olufajo, O. (2023). Cowpea breeding and production for food and nutritional security in sub-Saharan Africa. Plants, 12(3), Article 611.
  7. Desai, S., & Amaresan, N. (2022a). Qualitative and quantitative estimation of phosphate-solubilizing actinobacteria. In Springer Protocols Handbooks (pp. 589-593). Springer.
  8. Desai, S. & Amaresan, N. (2022b). Qualitative and quantitative evaluation of mineral phosphate solubilization by rhizosphere bacteria. Journal of Applied Microbiology, 132(4), 2140-2152.
  9. Du, J., Zhang, L., & Wang, Y. (2026). Phosphate-solubilizing Bacillus subtilis Y31 promotes cucumber growth and yield: Insights from rhizosphere microbiomics and bacterial genomics. BMC Microbiology, 26, Article 12835.
  10. Fadiji, A. E., Xiong, C., Egidi, E., & Singh, B. K. (2024). Formulation challenges associated with microbial biofertilizers in sustainable agriculture and paths forward. Journal of Sustainable Agriculture and Environment, 3(3), 324-349.
  11. Fang, T., Liu, X., & Zhou, J. (2025). Enhancing soil health through balanced fertilization: A pathway to sustainable agriculture and food security. Frontiers in Microbiology, 16, Article 1536524.
  12. Fasusi, O. A., Cruz, C., & Babalola, O. O. (2021). Agricultural sustainability: Microbial biofertilizers in rhizosphere management. Agriculture, 11(2), Article 163.
  13. Gupta, A. K., Kumar, A., & Singh, R. (2021). Phosphate-solubilizing microorganisms: A review. In R. S. Meena (Ed.), Nutrient dynamics for sustainable crop production (pp. 231-244). Springer.
  14. Kumar, A., Prakash, O. & Singh, K. (2022). Phenotypic and molecular characterization of plant growth-promoting rhizobacteria isolated from economically important crops. Microbiol Res, 258(2),106–118.
  15. Li, S., Li, Y., Yan, X., Gu, Z., Xue, D., Wang, K., Yang, Y., Lv, M., Han, Y., Li, J., Lv, Y., & Hu, A. (2026). Long-term organic fertilization enhances soil fertility and reshapes microbial community structure with decreasing effects across soil depth. Microorganisms, 14(1), Article 250.
  16. Massawe, C. P., & Mndiga, H. S. (2025). Performance of cowpea varieties under different phosphorus levels and spacing in Tanzania. Cogent Food & Agriculture, 11(1), Article 2595295.
  17. Menezes-Blackburn, D., Giles, C., Darch, T., George, T. S., Blackwell, M., Stutter, M., Shand, C., Lumsdon, D., Cooper, P., Wendler, R., Brown, L., Almeida, D. S., Wearing, C., Zhang, H., & Haygarth, P. M. (2023). Soil phosphorus dynamics and sustainable phosphorus management in agriculture. Agriculture, Ecosystems & Environment, 342, Article 108131.
  18. Ngo Nkot, L., Timb, S. A. L., Nyouma, A., & Rapsia, D. (2021a). Screening and optimization of Indole-3-Acetic Acid production by cowpea (Vigna unguiculata L. Walp.) Rhizobia isolates. American Journal of Plant Sciences, 16(6), 774-786.
  19. Ngo Nkot, L., Nwaga, D. & Amougou, A. (2021b). Phytohormone production efficiency and quantification of indole-3-acetic acid synthesized by indigenous Enterobacter strains. Biotechnology Letters, 43(3), 675-684.
  20. Noumsi-Foamouhoue, A. T., Mycorrhizal, F., & Beneficial, M. (2026). Synergistic effect of organic waste products and microbial inocula on iron and zinc biofortification in cowpea [Vigna unguiculata (L.) Walp.]. Food Science & Nutrition, 14(2), 412-425.
  21. Ojo, O. T. (2022). Taxonomic resolution and functional analysis of leguminous rhizobacteria within the Niger Delta basin. African Crop Science Journal, 30(1), 45-59.
  22. Omuta, G. E. D. (2020). Urbanization and environmental sustainability in Benin City, Nigeria. Journal of Environmental Management, 1, 7–18.
  23. Patel, K. R., Shah, S. B., & Patel, M. S. (2021). Isolation, screening, and selection of phosphate-solubilizing bacteria from tropical agricultural soils using serial dilution techniques. International Journal of Agronomy, 2021(8), 12-25.
  24. Pikovskaya, R. I. (1948). Mobilization of phosphorus in soil in connection with the vital activity of some microbial species. Mikrobiologiya, 17, 362-370.
  25. Raghothama, K. G., & Karthikeyan, A. S. (2022). Phosphorus acquisition and utilization in plants: Current advances and prospects. Plant Physiology Reports, 27(2), 225-239.
  26. Rani, M., & Singh, A. (2021a). Preparation, process, and significance of biofertilizers. International Journal of Green Chemistry, 10(1), 1–8.
  27. Rani, P. & Singh, R. (2021b). Mass multiplication, liquid culture scale-up, and production kinetics of carrier-based biofertilizers. Journal of Agricultural Biotechnology, 14(3), 310-322.
  28. SAS Institute Inc. (2021). SAS 9.4: Analysis of Variance (ANOVA) Output (Statistical output). SAS Institute Inc. https://www.sas.com
  29. Sudharani, Y., Mohapatra, P. P., Pramanik, K., & Maitra, S. (2021). Effect of different phosphorus levels on growth and yield of cowpea (Vigna unguiculata L) genotypes. International Journal of Management, Technology and Engineering, 8, 76–89.
  30. Tamura, K., Stecher, G., & Kumar, S. (2021). MEGA11: Molecular Evolutionary Genetics Analysis version 11. Molecular Biology and Evolution, 38(7), 3022-3027.
  31. Tennakoon, N. S. (2021a). Phosphate-solubilizing bacteria: A potential tool for sustainable agriculture (Master's thesis). University of Peradeniya.
  32. Tennakoon, B. M. (2021b). Biometric and biomass partitioning analysis of grain legumes under varying bio-inoculation and fertilization regimes. Field Crops Research, 264(5), 108-121.
  33. Umar Y. M., Silas, K., Yaumi, A. L., & Kwaji, B. H. (2022a). A review of biofertilizer production: Bioreactor, feedstocks, and kinetics. SSRG International Journal of Recent Engineering Science, 9(1), 39-50.
  34. Umar, S. A., Bello, M., & Abubakar, Z. (2022b). Blending parameters and quality control parameters of carrier-based biofertilizers under tropical laboratory conditions. International Journal of Recycling Organic Waste in Agriculture, 11(2), 195-207.
  35. Wang, M., Wang, X., & Zhang, H. (2026). The phosphate-solubilizing capacity of Rhizobium tropici LNP6 and its growth-promoting effects on Ormosia hosiei seedlings. BMC Plant Biology, 26, Article 12955.
  36. Wu, L., Zhang, Y., & Liu, T. (2026). The combined application of chemical and microbial fertilizers enhanced microbial diversity and improved soil fertility in the peanut rhizosphere within a sugarcane-peanut intercropping system. Frontiers in Microbiology, 17, Article 1751211.
  37. Zhou, Y., & Zhao, Q. (2026). Phosphate-solubilizing bacteria: A review of diversity, mechanisms, and applications in sustainable agriculture. Frontiers in Microbiology, 17, Article 1778470.