Rice production faces dual challenges of climate change and cadmium (Cd) contamination, threatening global food security. In response, biochar (BC) emerges as a promising 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. A meta-analysis spanning 2000–2023 evaluated BC’s impact on paddy soils, focusing on greenhouse gas (GHG) emissions, Cd bioavailability, accumulation, and rice yield.

Results revealed significant 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 increase (18%) and soil organic carbon (SOC) enhancement (9%) with sewage sludge and bamboo chips BC application, respectively. BC reduced soil bulk density (8%) and CH4 emissions (2%), with notable reductions in CO2 emissions (7–8%) and Cd bioavailability (24%). Moreover, Cd accumulation in rice grains decreased substantially (13–25%) with BC application, particularly with sunflower seedshells and rice husk-based BC.

Recommended BC application rates of 51–100 t/ha improved soil properties and rice yields, with cotton sticks-based BC notably boosting yields by 37% in Cd-contaminated paddy soil. The meta-analysis underscores BC’s multifaceted benefits in promoting sustainable and resilient rice cultivation.

Climate change exacerbates food security concerns, particularly in rice production, which is highly susceptible to temperature shifts. Rising temperatures diminish rice yields, impacting global food supply. Additionally, agriculture contributes significantly to GHG emissions, with paddy fields serving as substantial GHG sources.

Heavy metal contamination, particularly Cd, poses threats to soil, vegetation, and human health. Cd’s translocation into rice grains hampers plant growth and reduces yields. Addressing these challenges requires strategies to mitigate GHG emissions and reduce heavy metal accumulation in rice.

BC, derived from organic biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, offers a sustainable solution. Its application enhances soil properties, reduces GHG emissions, and mitigates Cd contamination in paddy soils, thereby improving rice yields. This meta-analysis consolidates existing research, emphasizing BC’s efficacy in promoting sustainable rice cultivation amidst environmental challenges.