Corn and hardwood biochars affected soil microbial community and enzyme activities

Abstract Biochar has gained interest as a soil amendment to improve soil quality and as means to help mitigate climate change. With the recent focus given to the soil as a living system and the essential functions it provides, knowledge of different effects of biochar on the microbial community is critical. A laboratory incubation (120 d) study was conducted on a Bennington silt loam (fine, illitic, mesic Aeric Epiaqualf) amended with corn ( Zea mays L.) and hardwood biochars produced under slow pyrolysis. Biochars were analyzed for their chemical and physical properties and were added to the soil on a C content basis without exceeding 2.5% w/w. Microbial community abundance and composition were evaluated by phospholipid fatty acids (PLFA) analysis, and potential enzyme activities by β‐glucosidase, and fluorescein diacetate (FDA) hydrolysis. There were no significant differences in the abundance of saprophytic fungi or bacteria in samples incubated with biochars when compared to the control. However, soils incubated with corn biochar had significantly ( P < .05) higher abundance of Actinobacteria markers than hardwood biochar. The FDA hydrolysis did not show significant differences between soils incubated with biochar when compared with the control. Conversely, the β‐glucosidase activity was significantly higher ( P < .05) in soils incubated with either biochar than in control. Since biochar can influence changes in microbial community composition and enzyme activity it may influence cellulose degradation and soil organic matter dynamics in the agricultural soil evaluated.