Inorganic amendments increase soil carbon sequestration across global acidic agroecosystems: A meta-analysis

Inorganic amendments, including lime, gypsum, and calcium-based soil conditioners, are widespread for soil acidification mitigation, enhancing nutrient availability, and boosting crop productivity. However, their impacts on soil organic carbon (SOC) remain inconsistent and incompletely quantified worldwide. To evaluate the global influence of inorganic amendments on SOC dynamics and crop productivity in acidic agroecosystems, we examined data from 269 independent field experiments, encompassing 6,034 observations, via meta-analysis. Our findings indicate that inorganic amendments significantly increased SOC concentration by an average of 2.8% and crop yield by 14.6%. These SOC alterations are impacted by crop types, duration, initial SOC, CaO input, and aridity index. Crop rotation and composite amendment are critical for enhancing organic carbon levels. Applying inorganic amendments to chemically fertilized soil is more effective at elevating SOC than when applied to organically fertilized soil. The changes in critical factors between these two fertilizer types highlight the importance of soil nutrient levels and microbial activity in carbon cycling. Moreover, the positive correlation between response ratios (RR) of SOC and RR of yield indicates that enhancing organic carbon can improve soil productivity. Overall, inorganic amendments are a viable management strategy for increasing soil carbon sequestration in acidic agroecosystems and are essential for predicting carbon feedback in upcoming global acidification scenarios.