Biochar Amendments Alter Soil Microbial Community Abundance, Activity and Diversity: Is This a Good Thing for Organic Agriculture?

We have studied microbial community dynamics in terra preta soils of the Brazilian Amazon, rich in black carbon; and in temperate soils amended with corn stover biochar, planted to corn, in NY State. In the terra preta soils, Bacteria and Archaea responses were studied; whereas in NY, we focused on Bacteria and Fungi. Abundance was measured by plate and liquid culturing and by microbial biomass estimates. Activities examined include carbon respiration and soil hydrolytic exoenzyme activities. Diversity was investigated by SEM, T-RFLP DNA fingerprinting and cloning and sequencing of Archaea, Bacteria and Fungi from the two regions. In general, soils high in black carbon and those amended with biochar harbor microbial communities that are more abundant, more active, release lower amounts of important greenhouse gases, and are highly divergent genetically from those in unamended soils. Other studies have shown that root growth and fungal hyphal extension are stimulated in the presence of biochar. Hold on though - before you go out and blanket your land with biochar – best to find out if biochar application is a desirable practice for enhancing the ecosystem services provided by the biotic component of soils under your care.