Evolutions of different microbial populations and the relationships with matrix properties during agricultural waste composting with amendment of iron (hydr)oxide nanoparticles

Abstract

This study investigated the evolutions of different microbial populations and multivariate relationships between their abundances and environmental variables during composting with amendment of Fe (hydr)oxide nanoparticles. Piles treated with nanohematite and nanomagnetite were denoted as T-nanohematite and T-nanomagnetite, and another one was T-control. It was found that nanohematite more effectively increased bacteria and fungi abundances with 1.24∼1.58 times average value of T-control, while nanomagnetite was more useful to actinomycetes. As the most significant variable, the total effect of temperature in T-control and T-nanomagnetite was increased to 0.87 and 0.92, respectively, because both the direct and indirect effects were positive, while it in T-nanohematite was reduced to 0.18 by the negative indirect effect. Partial redundancy analysis suggested that each microbial abundance shared different relationships with composting parameters. Overall, actinomycetes was more sensitive to changes of composting parameters than bacteria and fungi.

Keywords: Composting; Fe (hydr)oxide nanoparticles; Microbial populations; Partial least-squares path modeling; Redundancy analysis.