Biochar's dual impact on soil acidity management and crop yield enhancement: a meta-analysis

Abstract

Abstract Background and Aims Biochar is a promising and widely used soil amendment to alleviate soil acidification and improve crop productivity. Quantitative analysis of the impact of biochar application on soil pH and crop yield can help promote its optimal utilization. Methods We compiled 654 observations from 105 peer-reviewed articles to investigate the impact of biochar application on crop yield, soil pH and other physicochemical properties in acidic soils. Results Application of biochar significantly increased soil pH and crop yield by 11% and 49%, respectively. The increase in soil pH exhibited a positive correlation with crop yield, and the relationship varied among crop type. The most significant increase in soil pH and crop yield following biochar application was observed in strongly acidic soils (pH < 4.5) characterized by low cation exchange capacity, ranging from 5 to 10 cmol kg− 1, and low soil organic matter content, < 6 g kg− 1. Among soil physicochemical properties, biochar application increased soil organic matter, cation exchange capacity, and cation saturation by 54%, 33% and 43%, respectively, while reduced soil bulk density by 11%. Biochar derived from herbaceous sources and pyrolyzed at an optimal temperature of 300–400°C had a significant and positive affect on soil pH (+ 16%) and crop yield (+ 71%). Conclusion Our findings can aid in optimizing management strategies for biochar application on acidic soils, whereas more long-term field experiments should be conducted to help provide better explanations for changes in biochar properties as it ages.