Biochar and organic fertilizer reshape soil microbes to support sustainable dryland farming
image: The application of biochar and organic fertilizer substitution regulates the diversities of habitat specialist bacterial communities within soil aggregates in proso millet farmland
Credit: Lixin Tian, Yawei Wang, Doudou Jin, Yulong Zhou, Bauyrzhan Mukhamed, Dan Liu & Baili Feng
A field study reveals that combining biochar with organic fertilizer can significantly improve soil structure, nutrient availability, and beneficial microbial communities in dryland farming systems, offering a promising pathway toward more sustainable agriculture.
The research, conducted on proso millet farmland in China’s Loess Plateau, examined how different fertilization strategies influence soil health at a microscopic level. Scientists found that integrating biochar with organic fertilizer not only enhanced soil fertility but also reshaped bacterial communities in ways that could improve long-term ecosystem stability and crop productivity.
“Soil microbes are essential for nutrient cycling and plant growth, but their responses to different soil management practices are still not fully understood,” said lead author Lixin Tian. “Our findings show that combining biochar with organic fertilizer can create a more favorable environment for specialized microbial communities that drive key soil processes.”
Biochar, a carbon-rich material produced by heating plant biomass in low-oxygen conditions, has gained attention for its ability to improve soil properties. However, it is often less effective when used alone compared to traditional fertilizers. This study highlights the benefits of combining biochar with organic nutrient sources.
In field experiments, researchers compared six treatments, including conventional nitrogen fertilizer, organic fertilizer substitution, and combinations with biochar. They analyzed soil aggregates of different sizes and assessed nutrient levels, enzyme activities, and bacterial diversity.
The results showed that the combined treatment of biochar and organic fertilizer increased the proportion of larger soil aggregates while reducing smaller, less stable particles. Larger aggregates are important because they help retain water and nutrients, improving soil resilience in semi-arid environments.
At the same time, this treatment significantly increased soil organic carbon, total nitrogen, and available nitrogen forms such as ammonium and nitrate. These improvements were accompanied by higher activity of enzymes involved in carbon, nitrogen, and phosphorus cycling, indicating enhanced microbial functioning.
One of the most striking findings was the effect on bacterial communities. The combined treatment increased the richness of habitat specialist bacteria, which are microbes adapted to specific environmental conditions and often play critical roles in nutrient cycling. In contrast, generalist bacteria, which can survive in a wide range of conditions, were less affected.
Further analysis revealed that these specialist communities formed more complex and interconnected ecological networks when biochar was applied. Such networks are often associated with greater stability and resilience, suggesting that the soil ecosystem becomes more robust under this management strategy.
The study also identified ammonium nitrogen as a key factor shaping microbial community structure across different soil aggregates. Despite these changes, the overall assembly of microbial communities was largely driven by random processes, highlighting the complexity of soil ecosystems.
“These results provide new insights into how sustainable soil management practices influence microbial ecology at multiple scales,” Tian said. “They also offer practical guidance for improving soil health and crop productivity in dryland regions.”
As climate change and soil degradation continue to challenge global agriculture, strategies that enhance soil structure and microbial function are becoming increasingly important. The integration of biochar with organic fertilizers could represent a scalable solution for maintaining productivity while reducing reliance on chemical inputs.
The researchers suggest that future studies should explore long-term impacts and test these approaches across different crops and environments to further validate their benefits.
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Journal Reference: Tian, L., Wang, Y., Jin, D. et al. The application of biochar and organic fertilizer substitution regulates the diversities of habitat specialist bacterial communities within soil aggregates in proso millet farmland. Biochar 7, 6 (2025).
https://doi.org/10.1007/s42773-024-00398-z
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.