In the journal Environmental Technology & Innovation, Lan et al., explore the intricate relationship between biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, a soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More, and the chemistry of soybean roots. The study reveals that while biochar can alleviate allelopathy—the harmful effects of biochemicals produced by plants—it also introduces stress factors that trigger defensive responses in soybeans. This research highlights the dual nature of biochar, demonstrating its potential benefits and the need for careful application to avoid unintended consequences.  

The researchers applied different types of biochar to soybean plants and meticulously analyzed the plants’ responses. They discovered that biochar influences the production of allelochemicals, specifically suppressing benzoic acid (BA) while promoting salicylic acid (SA) generation in soybean roots. This shift is significant because BA and SA play critical roles in how plants respond to environmental challenges.  

Further analysis uncovered that biochar’s effects are linked to its capacity to retain vital nutrients like phosphorus and ammonium, as well as the presence of persistent free radicals (PFRs). The retention of phosphorus, in particular, was identified as a key factor driving SA production, suggesting that soybeans produce SA to help solubilize phosphorus in the soil. Additionally, the study found that biochar can induce oxidative stress, leading to the accumulation of malondialdehyde, a marker of oxidative damage.  

In conclusion, this research elucidates the complex interactions between biochar and soybean plants, revealing that biochar’s application can trigger both beneficial and stress-induced responses. Understanding these dual effects is crucial for developing sustainable agricultural practices that maximize the benefits of biochar while minimizing potential ecological risks.

SOURCE: Lan, P., Chen, Q., Wu, M., Oleszczuk, P., & Pan, B. (2025). Oligotrophy biochar stimulates the generation of salicylic acid from soybean roots by increasing nutrient and oxidative stress. Environmental Technology & Innovation, 38, 104083.