Rhizobacteria inoculation in maize associated with nitrogen and zinc fertilization at sowing

Abstract

Rhizobacteria have a wide range of plant growth-promoting mechanisms of action, making them an alternative and/or complementary biological input for chemical fertilizers. In this respect, the present study aimed to assess growth and nitrogen accumulation in maize plants as a function of Azospirillum brasilense, Bacillus subtilis, zinc and nitrogen application at sowing. The experiment with the ‘AL Bandeirante’ maize variety was conducted in a greenhouse, using a completely randomized design. The treatments were arranged in a 2 x 2 x 2 x 2 factorial scheme, with six repetitions, considering the presence and absence of Azospirillum brasilense (5 g kg-1), Bacillus subtilis (5 mL kg-1) and zinc (20 g kg-1) in the seeds and addition or not of nitrogen (30 kg ha-1) to the soil. The variables assessed were plant height, stem diameter, leaf, stem, shoot, root and total dry weight, and shoot nitrogen content. Nitrogen fertilization in the absence of zinc increased shoot and total dry weight as well as shoot nitrogen content. Zinc applied to the seeds improved the total and stem dry weight of maize plants in the absence of Bacillus subtilis. Inoculation with Azospirillum brasilense and Bacillus subtilis increased the stem diameter and shoot nitrogen content of maize plants when nitrogen fertilization was not performed at sowing. There was no isolated or interaction effect between factors for plant height and root dry weight.

Co-inoculation With Tropical Strains of Azospirillum and Bacillus Is More Efficient Than Single Inoculation for Improving Plant Growth and Nutrient Uptake in Maize.

“…In another study, inoculation with A. brasilense and B. subtilis increased the stem diameter and shoot N content of maize plants when N fertilization was not used at the sowing. The authors concluded that the observed increases indicate a synergy between the two microorganism species, demonstrating that, in this case, their combined inoculation in maize reduced the need for N fertilization at sowing (Moreno et al 2021). Combined inoculation of Azospirillum and a P-solubilizer (B. megaterium var.…”

“…Genes involved in the production of low molecular weight organic acids, P and N metabolism were identi ed in the genome of Bacillus strains (Velloso et al 2020) and they have also been described as bene cial to plant growth for their e ciency in phosphate solubilization and organic acid production (Gomes et al 2014;Abreu et al 2017;Ribeiro et al 2018). In addition, relevant results regarding Azospirillum co-inoculated with different bacterial species have been described in the literature (Gómez-Godínez et al 2019; Moretti et al 2020;Rondina et al 2020;Moreno et al 2021). There is an increasing adoption of the co-inoculation of Azospirillum and Bradyrhizobium by soybean farmers in Brazil over the last years.…”

Consortium of multifunctional microorganisms in soybean culture

“…ANDREOTE, 2016). The microorganism-plant interaction can promote the growth of living organisms in the system and intensify the plants' tolerance to biotic and abiotic stresses (MORENO et al, 2021).…”

“…Recent studies show the beneficial effects of multifunctional microorganisms in increasing shoot dry biomass and productivity of soybean (SILVA et al, 2020b;CHAGAS JUNIOR et al, 2022) and common bean (Phaseoulus vulgaris) (REZENDE et al, 2021a); growth promotion of rice (Oryza sativa L.) (FERNANDES et al, 2021;PARRALES et al, 2022) and accumulation of N in maize plants (Zea mays) (MORENO et al, 2021). In addition, the use of different beneficial microorganisms at the same time, defined as coinoculation or consortium of microorganisms, has been gaining market share, since it adds different mechanisms of action, producing potential synergistic effects, compared to the use of isolated microorganisms (FLAUZINO et al, 2018).…”

Co-inoculation with tropical strains of Azospirillum and Bacillus is more efficient than single inoculation for improving plant growth and nutrient uptake in maize

“…Interestingly, they hypothesized that bio lm formation induced by root exudates in Bacillus and Azospirillum forming aggregates may provide favorable nitrogen-xing conditions by protecting bacteria from oxygen, or the consortia may provide nutrients that stimulate Azospirillum nitrogen xation.In another study, inoculation with A. brasilense and B. subtilis increased the stem diameter and shoot N content of maize plants when N fertilization was not used at the sowing. The authors concluded that the observed increases indicate a synergy between the two microorganism species, demonstrating that, in this case, their combined inoculation in maize reduced the need for N fertilization at sowing(Moreno et al 2021). Combined inoculation of Azospirillum and a P-solubilizer (B. megaterium var.…”