Efficacy of bio-fertilizers and chemical fertilizers on growth and yield of cowpea varieties

Abstract

Cowpea is valued for its nutrition and nitrogen-fixing ability, and investigating bio-fertilizers offers a sustainable way to enhance cowpea growth and yield. A field experiment was conducted from February to June 2022 in the Nawalparasi West, Nepal, to investigate the impact of different fertilizers, including bio-fertilizers and chemical fertilizers, on the growth parameters and yield of cowpea varieties. Employing a double factorial Randomized Complete Block Design (RCBD), the experiment considered two factors: cowpea varieties (Malepatan-1 and Stickless) and fertilizers (control, mycorrhizal, rhizobia, recommended dose of chemical fertilizer (RDF), mycorrhizal + rhizobia, and mycorrhiza + rhizobium + RDF). Malepatan-1 exhibited superior growth and yield compared to Stickless, with higher plant height (125.73 cm), seed weight plant−1 (72.29 g), thousand grain weight (151.62 g), and yield ha−1 (3,536.83 kg ha−1). While the application of rhizobia + mycorrhiza and chemical fertilizers increased various growth parameters, mycorrhiza + rhizobium showed comparable results in terms of yield (4,321.41 kg ha−1) and thousand grain weight (167.19 g) compared to the combination of the former (4,714.26 kg ha−1 and 176.83 g, respectively). Moreover, mycorrhiza + rhizobium demonstrated a higher benefit-cost ratio (3.76), making it economically and environmentally preferable to biofertilizers with chemicals. The study recommends mycorrhiza + rhizobium for its comparable yield, superior economic returns, and environmental sustainability over biofertilizers combined with chemicals. For maximizing economic and sustainable production, the study suggests using the Malepatan-1 cowpea variety with biofertilizers, excluding chemical (inorganic) fertilizers.

Keywords

• arbuscular mycorrhizal fungi
• bio-fertilizers
• cowpea
• integrated nutrient management
• rhizobium