Co-Inoculation of Rhizobium tropici and Rhizophagus clarus Combined with Swine-Waste-Based Organic Fertilization: Effects on Growth and Yield of Common Bean ( Phaseolus vulgaris L .)

The strategy of combining arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (NFB), blending them with organic compost made from swine wastewater (SWC) can give major boost to the growth and productivity of common bean (P. vulgaris L). This study assessed the effects of co–inoculation of R. tropici and R. clarus under varying doses of SWC on the growth and yield of common bean. The experiment was carried out in a greenhouse, following a completely randomized design. We compared five rates of compost application (0.0, 1.5, 3.0, 4.5, and 6.0 t ha−1) combined with microbial co-inoculation, and a control treatment with mineral nitrogen (N), phosphorus (P), and potassium (K) fertilizer (NPK) without inoculation, all with seven replicates. We measured several important factors: plant height and stem diameter, the dry weight of the plant (shoots and roots), chlorophyll levels (a, b, and total), the quantity and dry weight of nodules, the percentage of mycorrhizal colonization, the final grain yield, the count of seeds per pod and pods per plant, and the protein content. Co-inoculation of R. tropici and R. clarus combined with SWC application resulted in up to 78% increase in grain yield compared with mineral fertilization. These results improved chlorophyll content, biomass accumulation, and nodulation efficiency, highlighting the agronomic potential of co-inoculation strategies for sustainable nitrogen management. In summary, the co-inoculation strategy combined with organic fertilization from swine wastewater compost proved to be an effective way to boost growth, nitrogen assimilation, and grain yield in P. vulgaris cultivation.