Guan, et al (2024) Acidified 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 one-off application for saline-alkali soil improvement: A three-year field trial evaluating the persistence of effects. Industrial Crops and Products. https://doi.org/10.1016/j.indcrop.2024.119972

Saline-alkali soils, characterized by high salinity, alkalinity, poor structure, and low water retention, pose challenges to agriculture worldwide. This three-year field study in Xinjiang, China, investigated the use of acidified biochar as a one-off application to improve saline-alkali soil properties. Researchers tested palm fruit branch biochar modified with ferrous sulfate at four application rates (0, 10, 20, 30 t/ha) under varying irrigation levels (60%-120% ETc).

The study revealed that acidified biochar initially 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 slightly, but this effect disappeared by year three. Soil texture improved, with sand content increasing by up to 8.4%, and hydraulic properties showed sustained benefits, including a 16.7% rise in water holding capacityWater holding capacity is the amount of water that soil can retain. Biochar can significantly increase the water holding capacity of soil, improving its ability to withstand drought conditions and support plant growth.   More. Biochar also enhanced soil thermal insulation and reduced evaporation, although these effects diminished over time.

Optimal application rates depended on irrigation levels. Under adequate irrigation (100%-120% ETc), 15-20 t/ha was most effective, while under water-scarce conditions (60%-80% ETc), 20-25 t/ha yielded the best results.

This study highlights acidified biochar’s potential for enhancing soil structure, water retention, and thermal properties in saline-alkali soils. However, benefits reduced over time, suggesting that periodic reapplication may be necessary. These findings provide valuable insights for sustainable agriculture, particularly in areas with degraded saline-alkali soils.

By addressing a critical global issue, this research contributes to long-term soil health and food security.