Seed coating with inocula of arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria for nutritional enhancement of maize under different fertilisation regimes

ABSTRACT

Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria, responsible for enhancing plant nutrition, vigour and growth, may be used to reduce dosages of chemical fertilisers. Technologies that allow an economically viable and efficient application of these beneficial microbes in large scale agriculture must be studied. Seed coating is a potential delivery system for efficiently introducing minor amounts of bioinoculants. Despite the dramatic reduction on inoculum dose per plant, inoculation of AM fungi via seed coating was as effective as conventional soil inoculation. Fertilisation and inoculation had a significant impact on maize shoots nutrient concentrations. Different fertilisation regimes did not influence mycorrhizal colonisation. Plants without fertilisation and singly inoculated with R. irregularis showed shoot nutrient concentration increments of 110, 93, 88 and 175% for nitrogen, phosphorus, potassium and zinc, respectively, comparing with non-inoculated controls. Plants singly inoculated with P. fluorescens via seed coating under full fertilisation, presented enhancements of 100, 75 and 141% for magnesium, zinc and manganese, respectively, comparing with non-inoculated controls. Seed coating is a promising tool for delivering microbial inoculants into the soil, while promoting sustainable production of maize. This technology is particularly pertinent in low input agriculture, with potential environmental profits and food quality improvements.

KEYWORDS:

• Plant growth promoting microorganisms
• biofertilisers
• soil inoculation
• fertility
• sustainable agriculture

Acknowledgments

We thank Banco Português de Germoplasma Vegetal, Instituto Nacional de Investigação Agrária e Veterinária for providing the seeds.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

R.S. Oliveira, Y. Ma and I. Rocha acknowledge the support of Fundação para a Ciência e a Tecnologia (FCT) through the research grants SFRH/BPD/85008/2012, SFRH/BPD/76028/2011 and SFRH/BD/100484/2014, Fundo Social Europeu (FSE) and Programa Operacional do Capital Humano (POCH). This work was financed by national funds through FCT under the Project EXPL/AGR-TEC/1204/2013 and by Fundo Europeu de Desenvolvimento Regional (FEDER), Eixo I do Programa Operacional Fatores de Competitividade (POFC) of Quadro de Referência Estratégica Nacional (QREN) (COMPETE: FCOMP-01-0124-FEDER-041572). This work was also financed by FCT/MEC through national funds and the co-funding by the FEDER, within the PT2020 Partnership Agreement and COMPETE 2020, within the project UID/BIA/04004/2013.