Biochar amendment decreases soil microbial biomass and increases bacterial diversity in Moso bamboo ( Phyllostachys edulis ) plantations under simulated nitrogen deposition

Abstract

Biochar amendment has been proposed as a strategy to improve acidic soils after overuse of nitrogen fertilizers. However, little is known of the role of biochar in soil microbial biomass carbon (MBC) and bacterial community structure and diversity after soil acidification induced by nitrogen (N) deposition. Using high-throughput sequencing of the 16S rRNA gene, we determined the effects of biochar amendment (BC0, 0 t bamboo biochar ha −1 ; BC20, 20 t bamboo biochar ha −1 ; and BC40, 40 t bamboo biochar ha −1 ) on the soil bacterial community structure and diversity in Moso bamboo plantations that had received simulated N deposition (N30, 30 kg N ha −1 yr −1 ; N60, 60 kg N ha −1 yr −1 ; N90, 90 kg N ha −1 yr −1 ; and N-free) for 21 months. After treatment of N-free plots, BC20 significantly increased soil MBC and bacterial diversity, while BC40 significantly decreased soil MBC but increased bacterial diversity. When used to amend N30 and N60 plots, biochar significantly decreased soil MBC and the reducing effect increased with biochar amendment amount. However, these significant effects were not observed in N90 plots. Under N deposition, biochar amendment largely increased soil bacterial diversity, and these effects depended on the rates of N deposition and biochar amendment. Soil bacterial diversity was significantly related to the soil C/N ratio, pH, and soil organic carbon content. These findings suggest an optimal approach for using biochar to offset the effects of N deposition in plantation soils and provide a new perspective for understanding the potential role of biochar amendments in plantation soil.

Comparative Metagenomics Reveals Enhanced Nutrient Cycling Potential after 2 Years of Biochar Amendment in a Tropical Oxisol

“…Consistent with previous studies based on 16S rRNA gene amplicons, we showed that Proteobacteria and Bacteroidetes relative abundances significantly increased in biochar-amended samples and that the relative abundance of Acidobacteria decreased (22,24,35,44). Overall, all classes of Proteobacteria were more abundant in the biochar-amended samples, consistent with our previous study (22) in which we observed that biochar increased Proteobacteria abundance in the oxisol as early as 1 month and up to 1 year after the initial amendment.…”

“…However, previous reports on biochar functionality related to shifts in microbial community composition were often carried out in short-term studies (e.g., less than 1 year) (32,34,35,38,51). In contrast, studies have reported decreases in their relative abundance at least 2 years after the initial addition of biochar (44,52). Thus, the observed changes in Actinobacteria abundance are likely related to temporal shifts or driven by changes in organic carbon quality originating from plant litter and/or biochar (53).…”

Regulating Soil Bacterial Diversity, Enzyme Activities and Community Composition Using Residues from Golden Apple Snails

“…Bacterial diversity was highest in neutral soils and lower in acidic soils, with soils from the Peruvian Amazon the most acidic and least diverse in their study (10). Our results were consistent with the observations reported in biochar amendment by Q. Li et al (31), which found that bacterial diversity was relatively low in alkaline soils. We found that soil bacterial diversity increased with the additions of GAS residues and lime amendments between 0.5-2.5 g kg -1 , likely because of the shift from acidic to neutral soil pH.…”

Interaction of Biochar Amendment and Nitrogen Deposition on Soil Microbial Biomass Carbon and Enzyme Activity in a Torreya grandis Orchard

“…It is generally known that N addition can alter microbial biomass and activity in several ways [4,7]. Li et al [27] found that N deposition (30, 60, or 90 kg N ha −1 yr −1 ) significantly increased soil MBC in Moso bamboo (Phyllostachys edulis) plantations. However, a meta-analysis conducted by Treseder [6] showed that chronic N deposition significantly decreases MBC.…”