A phosphocompost amendment enriched with PGPR consortium enhancing plants growth in deficient soil

ABSTRACT

In the present study, we assessed the agronomic value of a formulated plant growth-promoting rhizobacteria (PGPR) consortium combined with a phosphocompost amendment in deficient soil, using three plant models (Phaseolus vulgaris, Zea mays, and Solanum lycopersicum). PGPR consortium contains four strains which have been identified as Pseudomonas sp. DN 13–01, Sphingobacterium suaedae T47, Bacillus pimilus X22, and Bacillus cereus 263AG5, respectively. They have previously displayed their P solubilizing capacity and to have PGPR traits. In this study, the four strains were able also to dissolve potassium (K), with K solubility (KS) indices range between 0.950.03 and 1.210.25 in solid medium and released K values between 30.251.21 and 45.230.84 g-L⁻¹in liquid medium. The bacterial strains also produced acid and alkaline phosphatases, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, protease, cellulase, pectinase, lipase and amylase enzymes. The amendment of deficient soil with phosphocompost enriched with the PGPR consortium increased much more soil productivity and plant growth compared with controls uninoculated. The formulated PGPR consortium combined with phosphocompost gave the best yield in terms of plant height, number of leaves, number of fruits, shoot biomass, root biomass, and dry shoot biomass of the three-plant studied. Simultaneously, the PGPR consortium inoculation increased P and K uptake in the shoots and available P and K in the soil. In summary, our results showed that the application of PGPR consortium combined with phosphocompost amendment increased plant growth in deficient soil.

KEYWORDS:

• Plant growth-promoting rhizobacteria
• Phosphocompost
• PGPR consortium
• Plant growth

Abbreviations

PGPR	=	plant growth-promoting rhizobacteria
ACC	=	1-aminocyclopropane-1-carboxylate
DS	=	deficient soil (poor)
PS	=	phosphate sludge
PC	=	phosphocompost
BC	=	bacterial consortium
PSB	=	phosphate solubilization bacteria
KSB	=	potassium solubilization bacteria

Acknowledgments

The authors would like to acknowledge the support through the R&D Initiative – Appel à projetsautour des phosphates APPHOS – sponsored by OCP (OCP Foundation, R&D OCP, Mohammed VI Polytechnic University, National Center of Scientific and Technical Research CNRST, Ministry of Higher Education, Scientific Research and Professional Training of Morocco MESRSFC) under the project entitled ’Procédés biotechnologiques pour la valorisation des boues et des déchets miniers de phosphate: Formulation d’un Phospho-compost bio-fertilisant pour application directe en agriculture productive et respectueuse de l’environnement » (Réf. BIO-MOD-01/2017).

Competing interests

The authors declare that they have no conflicts of interest.

Additional information

Funding

This work was supported by the Cherifian phosphate office (OCP) Foundation, R&D OCP, Mohammed VI Polytechnic University, National Center of Scientific and technical Research CNRST, Ministry of Higher Education, Scientific Research and Professional Training of Morocco MESRSFC [Projet. BIO-MOD-01/2017].