Acid tolerant Rhizobium strains contribute to increasing the yield and profitability of common bean in tropical soils

Abstract

Symbiosis of common bean with nitrogen-fixing bacteria can lead to a reduction in production costs and in environmental impacts. Considering the diversity of soils and climates, it is important to validate bacterial strains under different conditions to consolidate their recommendation as inoculants. Studies concerning the economic viability of Rhizobium inoculation in common bean are few, but they could assist in choosing the strain to be adopted. The aim of this study was to evaluate the performance of Rhizobium strains isolated from acid soils from the Amazon inoculated in seeds of the 'BRSMG Madrepérola' cultivar and to evaluate the economic viability of their use in the field. Four field experiments were conducted in the state of Minas Gerais, Brazil. A randomized block experimental design was used with four replications and seven treatments: inoculation with the strains CIAT 899 (Rhizobium tropici), UFLA 02-100 (R. etli), UFLA 02-68 (R. etli bv. mimosae), UFLA 02-127 (R. leguminosarum bv. phaseoli), and UFLA 04-173 (R. miluonense), plus two controls, one without inoculation + mineral nitrogen (N-urea) at a rate of 80 kg N ha -1 and another without inoculation and without mineral N. The strain CIAT 899 is already recommended for the manufacture of commercial inoculants, and the others, collected in the Amazon region, have proven to be highly effective in biological nitrogen fixation. Symbiosis of common bean with all the strains evaluated leads to satisfactory yields, with reduction in the application rate of mineral nitrogen and in environmental impacts and, consequently, reduction in economic costs, with higher profitability.

Isolation of Bacteria with Potential Plant-Promoting Traits and Optimization of Their Growth Conditions

“…It has in fact reported that increasing the pH of the rhizospheric soil may be an important consequence of N 2 fixation by bacteria [ 38 ]. On the other hand, Oliveira et al [ 39 ] examined five NFB bacterial strains and reported the pH of the culture medium after growth for four strains was neutral while another strain changed the pH to acidic.…”

Liquid Inoculation with Rhizobia in the Planting Furrow of Common Bean under No‐Till Is Feasible under Different Soil and Climatic Conditions

“…To meet the presuppositions of ANOVA, the data of number of nodules and nodule dry matter were first transformed in (x + 0.5) 0.5 . According to the official protocol for evaluation of viability and agronomic efficiency of strains, inoculants, and the literature (Fonseca et al, 2013;Figueiredo et al, 2016;Pádua Oliveira et al, 2017). This argument is pertinent, even though there is no dependence of the locations on the effects of the treatments on BSY.…”

Diversidade e eficiência simbiótica de rizóbios de solos de clima semiárido tropical com diferentes fertilidades

“…Estudos indicam que o fornecimento de N 2 pela simbiose de rizóbios e feijão-caupi varia de 15 a 99% da necessidade da leguminosa (NCUBE et al, 2007;NAAB;CHIMPHANGO;DAKORA 2009). Esta variação deve-se à diversidade funcional do isolados (JAISWAL; DAKORA, 2019) e boa capacidade de competição dos isolados selecionados por sítios de infecção nodular (Oliveira et al, 2017;Ferreira et al, 2019).…”