|JOHNSON, MARK - Environmental Protection Agency (EPA)|
Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2015
Publication Date: 11/3/2015
Citation: Ducey, T.F., Novak, J.M., Johnson, M.G. 2015. Effects of biochar blends on microbial community composition in two Coastal Plain soils. Agriculture. 5:1060-1075.
Interpretive Summary: Biochar, also known as black carbon, is any organic feedstock treated under high pressure and temperature with the express intention for use as a soil amendment. In this study we used feedstocks native to the southeastern coastal plain region in the form of poultry litter and pine chip. We added these biochars to two coastal plains soils in ratios based on phosphorus content. Using phospholipid fatty acid analysis as a measure of microbial community composition, we monitored the microbial responses to these amendments. Correlations between soil nutrient content – in the form of phosphorus and other micronutrients – and microbial response were found to be significant. The responses to biochar between the two soil types were markedly different, indicating that soil characteristics strongly influence the microbial response to soil amendments. This leads us to the conclusion that soil physical and chemical characteristics should be heavily considered when proposing to use biochar to amend soils.
Technical Abstract: The amendment of soil with biochar has been demonstrated to have an effect not only on the soil physicochemical properties, but also on soil microbial community composition and activity. Previous reports have demonstrated both positive and negative effects on soil microbial communities. These effects are modulated not only by the biochar composition, but also on the soils physicochemical characteristics. This indicates that soil characteristics must be strongly considered prior to biochar amendment. The significant portion of the soils of the southeastern coastal plain are severely degraded, and therefore candidates for biochar amendment to strengthen soil fertility. In this study we focused on two common soil series in the southeastern coastal plain, utilizing feedstocks endemic to the area. We applied these feedstocks in four ratios, looking at bioavailable nutrients via Mehlich-1 extractions, as well as microbial community composition using phospholipid fatty analysis (PLFA). Our results demonstrated significant shifts in microbial community composition in response to biochar amendment, the effects of which were greatest with 100% poultry litter biochar. Correlations of PLFAs with several Mehlich-1 extractable nutrients was observed.