Strategies for Improving Cowpea Grain Yield in the Eastern Amazon: Biological Nitrogen Fixation, Phosphorus Nutrition, and Molybdenum Seed Enrichment

ABSTRACT

This work aimed to evaluate the use of phosphorus (P) fertilizer, rhizobia inoculation, and seed enrichment with molybdenum (Mo) as tools for enhancing the cowpea yield in the Brazilian eastern Amazon. A set of field and greenhouse experiments were carried out in cerrado and upland forest environments. Four levels of P fertilization, eight rhizobia strains, and the application of mineral nitrogen (N) were evaluated for the cultivar BRS Tumucumaque (BR = Brasil e S = Sementes), and two levels of Mo seed enrichment were assessed for the cultivars BRS Tumucumaque and BRS Guariba. Grain yield increased linearly with the level of P applied. Inoculation with the rhizobia strain BR 3267 increased the shoot and nodule mass of the cultivar BRS Tumucumaque. There was no difference in grain yield and grain N accumulation between inoculation with seven rhizobia strains, N mineral fertilization and the control (without inoculation and N fertilization) in cerrado and upland forest environments. Cowpea grain yield and grain N accumulation were higher in the cerrado than in the upland forest environment and when the seeds were enriched with Mo. Phosphorus fertilization and seed enrichment with Mo are efficient tools to enhance cowpea yield in the Brazilian Amazon.

KEYWORDS:

• Cerrado
• latosol
• upland forest
• Vigna unguiculata

Acknowledgements

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (fellowships).

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Authors’ contributions

Wardsson Lustrino Borges: Conceptualization, Supervision, Methodology, Funding acquisition, Investigation, Formal analysis, Visualization, Project administration, Writing – original draft, review & editing. https://orcid.org/0000–0002–2960–0638

Natália dos Santos Ferreira: Formal analysis, Investigation, Writing – review & editing. https://orcid.org/0000–0003–0764–9278

Rayane da Mota Rios: Formal analysis, Investigation, Writing – review & editing. https://orcid.org/0000–0002–8764–9683

Mara Alexandre da Silva: Formal analysis, Investigation, Writing – review & editing. https://orcid.org/0000–0002–7337–3364

Adelson Paulo Araújo: Conceptualization, Supervision, Methodology, Investigation, Formal analysis, Visualization, Writing – original draft, review & editing. https://orcid.org/0000–0002–4106–6175

Rosângela Straliotto: Conceptualization, Methodology, Funding acquisition, Investigation, Project administration, Writing – review & editing. https://orcid.org/0000–0001–6804–2408

Jerri Édson Zilli: Conceptualization, Methodology, Funding acquisition, Investigation, Project administration, Writing – review & editing. https://orcid.org/0000–0003–2138–3488

Norma Gouvêa Rumjanek: Conceptualization, Methodology, Funding acquisition, Investigation, Project administration, Writing – review & editing. https://orcid.org/0000–0002–2174–1137

Additional information

Funding

This work was supported by the Empresa Brasileira de Pesquisa Agropecuária under Grant number 02.14.01.006.00.00.