Biochar Amendment to Degraded Soils: Differing Responses Amongst Soil Series and Chars.

The benefits of biochar as a soil amendment, is a topic that has received a wide degree of study. Despite this in-depth analysis, results vary as to how well individual biochars perform in particular soils. Therefore, we approached our study from the standpoint of using regional feedstocks of the southeastern Coastal Plain of the US, in soils endemic to the area. To this aim we utilized poultry litter (Gallus domesticus) and pine chip (Pinus taeda) as pyrolysis products for amendments into two Ultisol soil series (Coxville and Norfolk). Since microorganisms are responsible for a significant portion of soil nutrient cycling, we measured microbial phospholipid fatty acids (PLFA) as a proxy for soil fertility. Our results indicated that increasing amounts of poultry litter-derived biochar had a markedly greater effect on microbial PLFA’s in Norfolk soils as compared to the Coxville soils. However, changes in both soils were related primarily to an increasing shift in Gram negative microbial populations. These shifts in the microbial community appear to be predominantly in response to changes in both soil pH and soil P concentration. Additionally, PLFA’s predominantly used to measure microbial community stress were low, indicating that biochar amendment did not negatively impact the microbial communities. Overall, our results indicate that both feedstock and soil type are important considerations when considering biochar amendment, and that utilizing regional feedstocks can be potentially employed without deleterious effects to the soil microbial populations.