Bokashi Fertilization Improves Growth and Productivity of Cowpea Under Acidic Soil Conditions

Abstract

Background: Cowpea is a drought-tolerant, protein-rich legume widely grown in tropical regions, but its productivity is often constrained by acidic, low-fertility soils and nutrient limitations, particularly phosphorus and aluminum toxicity. Aims: To evaluate the agronomic performance of cowpea (Vigna unguiculata (L.) Walp.) cultivars grown in acidic soil under different bokashi doses. Study Design: A randomized block design in a 3 × 5 factorial arrangement with four replications was used. Place and Duration of Study: The study was conducted at the Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil, under greenhouse conditions, between October 2023 and February 2024. Methodology: The experiment was carried out in pots using acidic soil collected from an agricultural area characterized by intensive land use. Three cowpea cultivars (‘BRS Tumucumaque’, ‘BRS Imponente’, and ‘BRS Itaim’) and five bokashi doses (0, 1, 2.5, 5.0, and 7.5 g L⁻¹) were evaluated. Growth and yield variables, including plant height, stem diameter, number of pods, and grain yield, were assessed. Data were subjected to analysis of variance and regression analysis. Results: No significant interaction between cultivars and bokashi doses was observed. Cultivar effects were significant for most evaluated traits, while bokashi doses significantly influenced all analyzed variables. Regression analysis showed progressive increases in grain yield with increasing bokashi doses within the evaluated range, with the highest productive performance observed at 7.5 g L⁻¹. Conclusion: Bokashi fertilization improved the growth and productivity of cowpea cultivated in acidic soil, indicating its potential as a sustainable strategy for crop production under acidic tropical soil conditions. Nevertheless, the study was conducted over a single growing cycle and did not include post-harvest soil chemical analyses, which should be addressed in future research.