Effect of Rhizobium Inoculation on Growth of Common Bean in Low-Fertility Tropical Soil Amended with Phosphorus and Lime

Abstract

The cultivation of grain legumes (e.g., common bean) in sub-Saharan Africa contributes to the provision of food for a growing population and delivers environmental benefits such as inputs of nitrogen (N) to crops and soil via symbiotic nitrogen fixation (SNF). However, the success of SNF is constrained by several factors such as the poor efficiency of native rhizobial strains to fix N, the low availability of phosphorus (P) and the acidity of soils. Two trials have been conducted in low-fertility tropical soils at the smallholder farm scale in Madagascar to assess the effects of Rhizobium inoculation together with inputs of P and lime on the growth of the common bean. We showed that inoculation with native strains of Rhizobium had significant effects on bean root nodulation, which was increased by up to 15-fold on plant growth, which increased by 78% and on bean yield, which increased by 126%. Moreover, we observed positive and significant relationships between inoculation with Rhizobium and P fertilization on nodulation, plant growth and yield. However, the addition of dolomite lime did not show any effect in our study. The addition of P decreased the mycorrhization rate of roots. Additional research is still needed to improve our understanding of soil fertility conditions (mainly on nutrient availability, including micronutrients) allowing better efficiency of legume symbionts (rhizobium and mycorrhiza) in such low-fertility soils.

Post-Tin-Mining Agricultural Soil Regeneration Using Local Organic Amendments Improve Nitrogen Fixation and Uptake in a Legume–Cassava Intercropping System

“…The dolomite treatment, on the other hand, promoted N 2 -fixation, resulting in the lowest δ 15 N values (Figure 2A), but ultimately resulted in the lowest amount of N 2 fixed in terms of mass due to its shoot biomass being the lowest. Liming acid soils can improve macro-and micronutrient availability (such as P, Mo, Ca, and Mg) in soils, which can increase N 2 -fixation in legume species [18,19,22]. In the present study, however, no correlation between soil pH and δ 15 N was observed, suggesting that other factors may have contributed to this phenomenon.…”

“…The amount of N input via N 2 -fixation, a primary source of N in organic farming, is an important factor in the N balance of legume-based agroecosystems [14]. The application of soil amendments such as lime or dolomite increases N 2 -fixation in legumes, particularly in tropical soils [7,[17][18][19]. The increased availability of macronutrients (phosphorus, potassium, and sulfur) and micronutrients (boron and molybdenum) increase N 2 -fixation in legumes in soils amended with charcoal [20][21][22].…”

Seed Encrusting with Plant Nutrients Enhances Germination, Plant Growth and Yield of Soybean (Glycine max)

“…The traditional approach faces challenges, particularly during the cultivation season, where soil moisture is limited, hindering adequate moisture for seed germination. Moreover, soil degradation issues in soybean cultivation areas result in a deficiency of essential nutrients for the survival of rhizobia (Razafintsalama et al, 2022). Consequently, the rhizobia fixation of nitrogen becomes insufficient to promote the growth of soybeans in the cultivation area.…”

Plant-microbe interactions: mechanisms and applications for improving crop yield and quality

“…A recent study showed that inocu lation with Rhizobium strains along with the addition of phosphorus resulted in a significant increase in common bean nodulation, biomass production and overall yield. In field trials, bean yields on low fertility soils increased by an impressive 126 % (Razafintsalama et al, 2022). It was shown that pre-sowing inoculation of alfalfa plants with the active strains of Sinorhizobium meliloti led to an increased production of amino acids, in particular essential amino acids in above ground mass under optimal moisture and insufficient water supply (Kots et al, 2021), showing the role of nitrogen fixers in plant biofortification.…”