In a 2025 study published in 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, Zhang et al. examined how biochar amendments affect microbial stoichiometry, nutrient limitations, and carbon use efficiency in saline-alkali soils. The researchers compared the effects of acid-modified biochar (pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More 2.3) and alkaline biochar (pH 8.8) at different application rates (1%, 2%, and 5%) in soils planted with Medicago sativa L.  

Soil salinization is a major global issue, especially in arid and semi-arid regions where irrigation is common. This problem leads to decreased crop yields and reduced soil fertility by increasing salt concentration and pH, which in turn decreases nutrient availability and disrupts soil structure. Biochar, a carbon-rich material from organic feedstocks, has shown promise for improving soil conditions in these challenging environments.  

Biochar’s effectiveness depends on its properties, including surface area, porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More, and functional groups, which help retain nutrients. However, how biochar affects soil microbes in saline-alkali soils is complex. Factors like biochar’s pH, production temperature, and feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More influence its impact on microbial activity and soil health.  

The study’s results showed that alkaline biochar increased enzymatic carbon to nitrogen stoichiometry at higher application rates, while acid-modified biochar decreased it at lower rates. Both biochar types reduced enzymatic carbon to phosphorus and nitrogen to phosphorus stoichiometry. Alkaline biochar shifted microbial metabolism from nitrogen to phosphorus limitation, and at 2% and 5% application rates, it reduced microbial carbon limitation and increased carbon use efficiency. In contrast, acid-modified biochar did not enhance carbon use efficiency.  

The findings emphasize that biochar’s impact on soil microbial processes is influenced by its feedstock type, with differences in properties like pH and nutrient supply affecting soil properties, microbial communities, and plant growth. This research offers valuable insights for optimizing nutrient cycling and carbon sequestration in saline-alkali soils, highlighting biochar’s potential in sustainable soil management.  

SOURCE : Zhang, G., Zhang, L., Shi, Z., Yang, Y., & Liu, J. (2025). Microbial nutrient limitation and carbon use efficiency in saline-alkali soil amended with biochar: insights from ecoenzymatic C:N:P stoichiometry. Biochar, 7(1), 68.