Biochar and Rhizobacteria Amendments Improve Several Soil Properties and Bacterial Diversity

Han Ren; Baoling Huang; Víctor Fernández-García; Jessica Miesel; Li Yan; Chengqun Lv

doi:10.3390/microorganisms8040502

Biochar and Rhizobacteria Amendments Improve Several Soil Properties and Bacterial Diversity

Microorganisms. 2020 Apr 1;8(4):502. doi: 10.3390/microorganisms8040502.

Authors

Han Ren¹, Baoling Huang¹, Víctor Fernández-García², Jessica Miesel³, Li Yan¹, Chengqun Lv¹

Affiliations

¹ Forestry College, Guangxi University, Daxue E Rd., Xiangtang District, Nanning 530004, Guangxi, China.
² Area of Ecology, Department of Biodiversity and Environmental Management, Faculty of Biological and Environmental Sciences, University of León, 24071 Leon, Spain.
³ Department of Plant, Soil and Microbial Sciences, Michigan State University, 1066 Bogue Street, East Lansing, MI 48824, USA.

Abstract

In the current context, there is a growing interest in reducing the use of chemical fertilizers and pesticides to promote ecological agriculture. The use of biochar and plant growth-promoting rhizobacteria (PGPR) is an environmentally friendly alternative that can improve soil conditions and increase ecosystem productivity. However, the effects of biochar and PGPR amendments on forest plantations are not well known. The aim of this study is to investigate the effects of biochar and PGPR applications on soil nutrients and bacterial community. To achieve this goal, we applied amendments of (i) biochar at 20 t hm^-2, (ii) PGPR at 5 × 10¹⁰ CFU mL^-1, and (iii) biochar at 20 t hm^-2 + PGPR at 5 × 10¹⁰ CFU mL^-1 in a eucalyptus seedling plantation in Guangxi, China. Three months after applying the amendments, we collected six soil samples from each treatment and from control plots. From each soil sample, we analyzed several physicochemical properties (pH, electrical conductivity, total N, inorganic N, NO₃^--N, NH₄⁺-N, total P, total K, and soil water content), and we determined the bacterial community composition by sequencing the ribosomal 16S rRNA. Results indicated that co-application of biochar and PGPR amendments significantly decreased concentrations of soil total P and NH₄⁺-N, whereas they increased NO₃-N, total K, and soil water content. Biochar and PGPR treatments increased the richness and diversity of soil bacteria and the relative abundance of specific bacterial taxa such as Actinobacteria, Gemmatimonadetes, and Cyanobacteria. In general, the microbial composition was similar in the two treatments with PGPR. We also found that soil physicochemical properties had no significant influence on the soil composition of bacterial phyla, but soil NH₄⁺-N was significantly related to the soil community composition of dominant bacterial genus. Thus, our findings suggest that biochar and PGPR amendments could be useful to maintain soil sustainability in eucalyptus plantations.

Keywords: 16S rNA; Bacillus megaterium; PGPR; microbial composition; physicochemical property.