How can livestock manure be managed so that its nutrients remain useful while the risks associated with antibiotic resistance are reduced? Our newly published article in the Journal of Environmental Chemical Engineering explores this question through the storage and fermentation of pig manure slurry (Cao et al., 2026).
The study examines the combined use of biochar and ferrous sulfate, bringing together two concerns that are central to circular nutrient management: the fate of antibiotic resistance genes and the transformation of nitrogen. I am pleased to share this publication with colleagues Yuang Cao, Zhuowu Li, Xiaoyu Xu, Jiahua Liu, Keqiang Zhang, Lianzhu Du and Suli Zhi.

Storage as an opportunity for intervention
Manure slurry contains nitrogen that can support agricultural production. It can also carry antibiotic resistance genes (ARGs), the genetic information that can enable microorganisms to resist antibiotics. The period before land application is therefore an important part of manure management. During storage and fermentation, changes in microbial communities and slurry chemistry can influence both nutrient availability and the persistence of resistance genes.
Our study focused on this stage using slurry collected from a pig farm in Tianjin, China. A 60-day laboratory experiment compared 13 treatment groups, with three replicate reactors per treatment, at approximately 30 °C. The treatments included biochar, ferrous sulfate, ferrous sulfate-modified biochar, physical mixtures of biochar and ferrous sulfate, and sulfuric acid, alongside an untreated control. Chemical measurements and metagenomic analysis were used to examine nitrogen forms, microbial communities and resistance-gene profiles.













