Xia, et al (2024) Acid-modified cotton straw 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 has instructive for the improvement of saline-alkali soil. Journal of Soils and Sediments. https://doi.org/10.1007/s11368-024-03800-2

Soil salinization is a significant barrier to agricultural productivity, reducing crop yields and degrading soil quality. Biochar, derived from organic materials like cotton straw, has shown promise in improving soil health. However, pristine biochar can exacerbate soil salinity issues. A recent study explored the potential of acid-modified biochar to address this problem effectively.

Researchers modified pristine biochar using nitric acid and phosphoric acid, creating two variants: nitric acid-modified biochar (NC) and phosphoric acid-modified biochar (PC). These were applied to saline-alkali soil in varying concentrations (1%, 2%, and 3%), with ten treatments in total.

The study’s findings highlighted that while pristine biochar increased soil 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 and electrical conductivity (EC)—key indicators of soil salinity—it also reduced the activity of critical soil enzymes. Conversely, acid-modified biochar showed remarkable improvements. Both NC and PC reduced the presence of harmful alkaline metals by over 79% and increased the soil’s specific surface area. This modification also significantly lowered the levels of sodium, chloride, sulfate, carbonate, and bicarbonate in the soil.

Importantly, the application of acid-modified biochar decreased soil pH by up to 0.59 units and EC by up to 789 μS.cm−1, enhancing soil nutrient availability and boosting the activity of nitrogen and phosphorus-acquiring enzymes.

In conclusion, while pristine biochar can worsen soil salinity, acid-modified biochar offers a promising solution. It reduces soil salinity, enhances nutrient availability, and supports enzyme activity, thereby facilitating the restoration of saline-alkali soils and promoting sustainable agriculture.