The global rise in carbon dioxide (CO2​) emissions from agricultural soils presents a significant challenge to achieving climate goals. In a recent study published in Environmental Earth Sciences, Anjali Thaitharanikathil Babu, Anand Madhavan, and K. P. Arunbabu investigated the potential of poultry litter 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 (PLB) to mitigate these emissions in the paddy wetland systems of Kunnukara village, Kerala, India. Their research specifically focused on comparing PLB with other organic amendments, such as raw poultry litter, mineral fertilizers, and current farming practices. The findings demonstrate that biochar prepared under specific conditions can significantly reduce CO2​ emissions, offering a more sustainable approach to rice cultivation in the region.

The study, conducted over a 120-day soil incubation period, focused on measuring the potential carbon mineralization (PCM) and CO2​ emissions from soils treated with various supplements. The most effective treatment, T5, utilized poultry litter biochar prepared at 350∘C for 30 minutes (PLB350-30). This specific biochar treatment reduced CO2​ emissions from 0.0408 to 0.0042 mgCO2​−C/g of soil, the most significant reduction observed in the study. In contrast, the current farming practices (T6), which include mineral fertilizers and cow dung, showed the lowest reduction in CO2​ emissions, decreasing from 0.041 to 0.022 mgCO2​−C/g of soil.

A key reason for the biochar’s effectiveness is its ability to induce a “negative priming effect” in the soil. This occurs when the biochar adsorbs organic matter, which reduces the rate of decomposition and, consequently, the rate of microbial respiration that releases CO2​. The PLB350-30 treatment showed a significant negative percentage variation in CO2​ emission from the control, with reductions of over 10%, 20%, 70%, and 85% by the 15th, 30th, 60th, and 90th days of incubation, respectively. The highest reduction, a negative percentage variation of -85%, was observed for T5 between 90 and 120 days. This is in stark contrast to the current farming practices (T6), which showed a positive variation of 70% on the 30th day, indicating a significant increase in CO2​ emission compared to the control soil.

The cumulative emissions data further reinforced these findings. The cumulative CO2​-C release for the PLB350-30 treatment (T5) was only 56.8±2.19 mg/kg, the lowest among all treatments. In comparison, the cumulative CO2​-C release for the current farming practices (T6) was 163±42.13 mg/kg, the highest recorded. These results are consistent with the properties of the biochar, as PLB350-30 had the highest fixed carbon content (15.2%) and the lowest volatile matterVolatile matter refers to the organic compounds that are released as gases during the pyrolysis process. These compounds can include methane, hydrogen, and carbon monoxide, which can be captured and used as fuel or further processed into other valuable products.   More to fixed carbon ratio (3.04), indicating its thermal stability and suitability for long-term carbon sequestration. The stable, fused-ring carbon structures within the biochar are essential for this long-term sequestration potential.

The study highlights that while raw poultry litter and current farming practices contribute to a higher release of CO2​ due to their readily decomposable nature and available nutrients, the use of biochar acts as a sustainable solution. By improving fundamental soil quality parameters like cation exchange capacity and 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 by creating stable carbon structures, biochar mitigates carbon emissions and helps combat global warming. The authors recommend that biochar be adopted as a sustainable 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 to replace synthetic fertilizers and other conventional practices in these vital agricultural regions.

Source: Babu, A. T., Madhavan, A., & Arunbabu, K. P. (2025). Characterization and carbon mineralization potential of poultry litter biochar in paddy wetland systems of Kunnukara village, Kerala, India. Environmental Earth Sciences, 84(459).