Mitigation of soil acidification is critical for reducing GHG emission and improving soil quality, crop yield and farm economic benefits: Evidence from a global meta-analysis

Soil acidification is a major threat to crop productivity and ecosystem health, which can be effectively mitigated by soil amendments. However, a comprehensive assessment of the impact of soil acidification mitigation on crop yield, soil properties, and greenhouse gas (GHG) emissions remains lacking. In this study, a meta-analysis was conducted by using field data obtained from 279 publications. The results showed that acidic soil amendment significantly increased soil pH by 6.27 %, base saturation by 86.1 %, cation exchange capacity by 19.5 %, and decreased soil exchangeable acidity and aluminum by 54.2 % and 64.4 %. In addition, the management also increased the organic matter content by 17.7 %, exchangeable calcium and magnesium by 102 % and 81.5 %. Meanwhile, the soil bacteria, fungi number increased by 36.2 %, 15.9 %, and microbial biomass carbon and nitrogen increased by 38.3 % and 45.3 % on average. Reduction in soil acidification increased CO₂ emission by 27.1 %, but decreased N₂O emission and CH₄ emission by 20.6 % and 12.3 %, respectively. The initial soil properties, climate, and the type of soil inputs were the major regulators of acidification control, and their effects were more pronounced in strongly acidic, coarse, low OM soils and in humid climate. Increasing soil pH improved yield varying from 8.95 % in rice to 82.6 % in rapeseed and decreased GHG emissions, returned a revenue gain of 798 USD ha⁻¹ through crop yield increase, carbon fixation and GHG emissions reduction. In conclusion, soil acidification mitigation significantly boosts food security and abates climate change challenges.