Effect of Rhizobacteria Inoculation via Soil and Seeds on Glycine max L. Plants Grown on Soils with Different Cropping History

Abstract

Field experiments testing the effect of phosphate-solubilizing rhizobacteria (PSRB) should consider the cropping history and the method used to inoculate the strains. We evaluated the hypothesis that PSRB previously isolated from soybean seedlings could be effective in promoting growth in this oilseed crop in soils with different cultivation periods. We also evaluated whether this growth promotion could be influenced by cultivation histories or the inoculation method (via seeds or soil). Thus, we conducted an experiment in five fields cultivating Glycine max during two seasons (2019/2020 and 2020/2021), to test the effectiveness of PSRB (SAF9-Brevibacillus sp., SAF11-Brevibacillus sp., and SAC36-Bacillus velezensis) compared with results observed for the inoculant BiomaPhos (mix of Bacillus subtilis and Bacillus megaterium). The present study was based on the evaluation of vegetative growth, nutritional and yield parameters, and microbial biomass carbon (MBC). PSRB were more effective than, or showed similar effectiveness to, BiomaPhos for most of the evaluated vegetative, nutritional, and yield characteristics. In the fields tested in the summer 2019/2020 crop, SAC36 and SAF9 strains stood out as growth promoters, whereas in the 2020/2021 crop, SAF11, SAC36, and BiomaPhos were notable. There did not seem to be a direct relationship between long histories of soybean cultivation as a monoculture and low yield in the field. However, yield seems to be associated with soil nutritional characters such as Ca, Mg, K, P, cation exchange capacity, and organic matter levels. PSRB inoculation positively affected nodulation (NN) and nodule dry mass (NDM) in the evaluated fields in the 2019/2020 crop, and the aerial part dry mass (APDM), NN, NDM, yield, and MBC of the evaluated fields in the 2020/2021 crop. In contrast, the inoculation method was observed to have a strong effect on APDM, NN, root dry mass, and MBC, as the plants inoculated via seed showed higher mean values than those in the plants inoculated via soil. This study demonstrated the growth-promoting potential of new phosphate-solubilizing strains, which may eventually be incorporated by the biostimulants market to freely compete with BiomaPhos.

Microorganismos multifuncionais na agricultura: uma revisão sistemática sobre bactérias solubilizadoras de fósforo

“…Cepas de Bacillus podem criar sideróforos que podem converter formas menos solúveis de fósforo em fosfatos (Santos et al, 2018) foi isolada da rizosfera do milho e tem a capacidade de solubilizar fosfatos de cálcio e de rocha, além de produzir fosfatase, enquanto a cepa de B. subtilis (CNPMS B2084) é endofítica, solubiliza fosfato de cálcio e de ferro e tem uma alta produção de ácido glucônico e da enzima fitase (Oliveira et al, 2020b;Velloso et al, 2020). Diversos trabalhos realizados demonstram sua eficiência no aumento da produtividade e acumulo de P na biomassa de culturas como soja (Oliveira et al, 2020a;Fiuza et al, 2022), milho (Oliveira et al, 2020a;Brito et al, 2022), milheto (Silva et al, 2021), feijão (Andrade, 2022), entre outras culturas de ciclo anual.…”

UAV Multispectral Data: A Reliable Approach for Managing Phosphate-Solubilizing Bacteria in Common Bean

“…Its action generally involves the release of low-molecular-density organic compounds through which their hydroxyl and carboxyl groups chelate the cations bound to insoluble phosphate, thereby promoting its solubilization [26]. The scientific community places adequate emphasis on its application to crops such as soybean [27,28], corn [29], and millet [30]. The common bean also has importance to agriculture and the bioeconomy.…”