Dairy Effluent-Saturated Biochar Alters Microbial Communities and Enhances Bermudagrass Growth and Soil Fertility

Sarbjeet Niraula,James P Muir,Kristen Payne,Woo-Suk Chang,Yong-Keun Choi,Eunsung Kan

doi:10.3390/agronomy11091794

Sarbjeet Niraula, James P Muir + Show 4 more

Open Access

https://doi.org/10.3390/agronomy11091794

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Abstract

Recently, biochar has been proposed for various agronomic applications including improved plant growth and soil fertility. In this study, the effects of dairy effluent-saturated (SBC) and unsaturated wood-derived biochar (UBC) on Bermudagrass (Cynodon spp.) growth, soil fertility and microbial communities were investigated in a greenhouse pot study. SBC and UBC were mixed with sandy loam soil at various loading rates (0, 1, 2, 4, and 8%) to grow Bermudagrass for 10 weeks. Soil physicochemical properties and plant growth measurements were taken, followed by 16S rRNA (V3-V4) amplicon sequencing of soil bacterial communities. Amendment of SBC to soil altered the soil physicochemical properties and increased the concentrations of N and P in the soil at 2 to 8% loading rates compared to UBC treated soil. The addition of SBC to soil also increased the overall plant biomass compared to UBC with more effects on aboveground biomass. Differential abundance analysis of taxa showed enrichment of Proteobacteria in UBC-amended soil, whereas Firmicutes and Nitrospirae were abundant in SBC-amended soil. Interestingly, enrichment of photosynthetic and N-fixing bacteria was observed in both SBC and UBC-amended soils after 10 weeks of treatments. However, oxidative phosphorylation and biotin metabolisms were found to be more abundant in SBC-amended soil compared to UBC-amended soil. Overall, our study suggested that amendment of SBC to soil resulted in enhanced soil nutrients, microbial capacity and Bermudagrass growth than that of UBC. Therefore, application of SBC to soil in field trials would be merited to identify sustainable and effective practices for enhancing plant growth, soil fertility and soil bacterial community.

Highlights

Biochar (BC) is a porous carbon material produced by thermal conversion of organic matter under limited oxygen concentration [1]
Saturating unsaturated wood-derived biochar (UBC) with dairy effluent resulted in distinct soil chemical properties compared to soil receiving UBC, as observed by discriminant analysis
This study investigated the effects of dairy effluent-nutrient loading and application rates on the growth of Bermudagrass, soil properties and microbial communities

Summary

Introduction

Biochar (BC) is a porous carbon material produced by thermal conversion (i.e., pyrolysis) of organic matter under limited oxygen concentration [1]. It exhibits a wide range of physicochemical properties based on feedstock [2], pyrolysis conditions [3], and nutrient saturation onto BC [4]. BC, as a soil amendment, increases fertility of soil [8] thereby enhancing crop yield and plant biomass [6] It increases cation exchange capacity (CEC) [9] and availability of organic carbon, and microbial activity [10] while providing buffering capacity to maintain appropriate pH [11,12]. The environmentally friendly nature of BC gives added benefits to its widespread use in agriculture

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