Narrative review explores hydrochar for reducing antibiotic resistance genes in grasslands

Photo by Etactics Inc / Unsplash

Frontiers in Medicine Published May 13, 2026 Medically reviewed May 13, 2026 DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Consider hydrochar as a potential but unproven intervention for reducing ARGs in grassland soils; direct evidence is lacking.

This narrative review synthesizes current knowledge on using hydrochar produced via hydrothermal carbonization as a soil amendment to mitigate antibiotic resistance genes (ARGs) in slurry-amended temperate grassland systems. The scope covers the potential for hydrochar to reduce ARG prevalence while maintaining soil function and microbial diversity, as well as the sustainability of hydrochar production.

The authors argue that hydrochar is a promising One Health intervention in slurry-soil-grassland systems, given its ability to sorb contaminants and alter microbial communities. However, they emphasize a critical limitation: direct evidence from hydrochar-based studies specifically targeting ARG reduction is lacking. Most supporting data come from related biochar research or laboratory experiments, not field trials with hydrochar.

Additional gaps include the absence of long-term field studies, unclear impacts on soil health over time, and insufficient data on the scalability and economic feasibility of hydrochar production. The review does not report specific effect sizes, sample sizes, or comparator treatments.

For clinicians and environmental health practitioners, the review highlights a potential strategy for reducing environmental ARG dissemination but underscores that the evidence base is too preliminary to guide policy or practice changes. Further research with hydrochar in real-world grassland systems is needed before recommendations can be made.

Study Details

Study typeSystematic review

EvidenceLevel 1

PublishedMay 2026

View Original Abstract ↓

Antibiotic resistance genes (ARGs) represent a growing global health concern, with agricultural practices, particularly livestock slurry application, serving as major contributors to their spread in soils. This review evaluates hydrothermal carbonization derived hydrochar as a potential One Health strategy for reducing ARG prevalence in slurry amended grassland systems. We synthesize current evidence on how hydrochar's properties and interactions within slurry-soil-grassland environments can limit ARG persistence, including its capacity to bind genetic material, affect microbial populations, and alter soil conditions that influence resistance dynamics. Where direct evidence from hydrochar based studies were lacking, findings from analogous materials such as biochar in related agricultural systems were used to elucidate the likely properties and impacts of slurry-derived hydrochar when applied to grassland slurry systems. In doing so, we highlight the potential of hydrothermal carbonization technology to contribute to addressing several environmental challenges in temperate grassland systems, where slurry management represents a persistent concern. Broader ecological and practical implications, such as impacts on soil function, microbial diversity, and the sustainability of hydrochar production, are also considered. Overall, this review highlights the potential of hydrochar as a tool for limiting the dissemination of ARGs from agricultural slurry and emphasizes the need for further research to optimize its application within sustainable grassland management. By synthesizing current evidence and identifying critical knowledge gaps, we propose hydrochar as a promising One Health intervention in slurry-soil-grassland systems and outline key research priorities required to realize its full potential.