Response of Rhizobacterial Community to Biochar Amendment in Coal Mining Soils with Brachiaria Decumbens as Pioneer Plant

ABSTRACT

Biochar has been used as an amendment for disturbed soils. However, the changes of the rhizobacterial community after the biochar addition in mine soils, has not yet been elucidated. The aim of this study was to evaluate the response in the rhizobacterial communities of Brachiaria decumbens during different reclamation processes of coal mining using biochar. Five treatments were carried out: control, mine soil + biochar, mine soil + biochar + Azospirillum brasilense, mine soil + biochar + arbuscular mycorrhizal fungal + Mortierella sp. DNA from the rhizospheric soil was sequenced by Ion Torrent. The relative abundance in each sample was calculated. The Proteobacteria (70%) and Actinobacteria (23%) phyla dominated the rhizobacterial community composition during the establishment time. Seven months after seeding, Actinobacteria decreased significantly, while Proteobacteria increased. The Acidobacteria phylum was higher in the control. There was a higher abundance of Proteobacteria with the biochar treatments than for the control, thus the baseline for the rhizobacterial community changes induced by biochar was provided. The alpha diversity index showed the effect of biochar on the diversity and dominance of the rhizobacterial communities. The hierarchical clustering tree showed a correlation between the treatments with biochar, and a significant differentiation between these and the control treatment.

KEYWORDS:

• Biochar
• Rhizobacterial community dynamics
• Brachiaria decumbens
• mine soil

Acknowledgments

The authors acknowledge the financial support of Colciencias (grant number 0424-2013), University of Antioquia and Sapiencia Enlaza Mundos Program (Colombia). We also thank the Centro de Biotecnología Genómica (Genomic Biotechnology Center) at the Instituto Politécnico Nacional (Mexico), especially Dr. Alberto Mendoza, who provided from his laboratory all of the resources that enabled this research to be conducted, and Lourdes Vital, who assisted in the initial analysis of the data. The authors would like to express their sincere gratitude to Dr. Jaime García Mena, who facilitated the infrastructure of the Genómica Ambiental (Environmental Genomics) Laboratory at Cinvestav (Mexico). We thank Dr. Luis Díaz from Universidad Popular del Cesar (Colombia), who donated the biochar and contributed as a collaborator in the research network, and Dr. Nelson Osorio from Universidad Nacional (Colombia), who donated the arbuscular mycorrhizal fungal inoculum.

Conflict of interest

The authors reported no potential conflict of interest.

Supplementary Material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by the Departamento Administrativo de Ciencia, Tecnología e Innovación [0424-2013].