Changes in microbial community structure due to biochars generated from different feedstocks and their relationships with soil chemical properties

- Microbial community variations in 4 biochars amended soil were studied by PLFAs.
- Microbial community changed after biochar induced the change of soil properties.
- Only PA 3% and BR 1% treatments were found to increase the PLFAs of protozoa.
- Application of some biochars could reduce environmental stress to soil organisms.

Biochars produced from swine manure (SM), fruit peels (FP), Phragmites australis (PA) and Brassica rapa (BR) were applied at different rates to a sandy loam soil at 70% moisture. Phospholipid fatty acid (PLFA) measurements showed that feedstock type, biochar type and application rate significantly affected the soil microbial communities. PLFAs derived from bacteria, fungi, actinomycetes, G + ve and G − ve bacteria and sulfate reducers were higher with FP biochar at 3% and 1% weight: weight (wt:wt), respectively, followed by SM at 1% and PA biochar at 3%, than in the control soil. The control soil also contained higher concentrations of certain iso:anteiso PLFAs, which are indicative of environmental stress, than did biochar treated soils. Protozoa PLFAs only increased in PA 3% and BR 1% treatments. Redundancy analysis illustrated the relationships between microbial communities and chemical properties within biochar types and addition rates to soil. The analysis indicated that different biochars induced different chemical changes such as increased pH, dissolved organic carbon and total carbon and nitrogen in soil and changed the microbial community structure. These properties may be used as indicators of both soil improvement and C sequestration.