Soil Organic Carbon Responses to Different Land Use Change: A Meta‐Analysis

ABSTRACT China has abundant reserves of soil organic carbon (SOC) and plays a key role in the global carbon cycle. The research on the influencing conditions of SOC based on land use types is insufficient, and the main factors need to be further studied. Here we conduct a meta‐analysis using 420 observations to explore the regularity of different land use types on SOC in China. The fail‐safe coefficient of environmental factors meets the standard of 5n + 10, and the data are heterogeneous, which can support the validity of the conclusion. Wetlands among the land use types have the most significant effect on the SOC, up to 11.5%. Soil depth of 20–40 cm has a significant positive effect on SOC, up to 15.2%. Compared with the control treatment, the mean average temperature of the grassland is 0°C–5°C, and the SOC content increases by 22.6%. The SOC of the farmland is significantly up to 22.9% when the mean annual precipitation ranges from 0 to 600 mm. Total nitrogen has a significant impact on SOC, reaching 28.9%. The results of the Random Forest model show that four environmental factors, namely land use types, climatic factors, geographic factors, and TN, have the most significant influences on SOC. SOC research is based on the combination of national special carbon sequestration policies and innovative measurement technologies, laying a theoretical framework and methodological support for related fields. Increasing land for carbon sinks and reducing carbon emissions can not only decrease the contribution of atmospheric carbon dioxide (CO 2 ) concentration but also contribute to achieving carbon neutrality. Our meta‐analysis will contribute to further elucidating the feedback of different land utilization on SOC in China and thus provide data support for soil carbon sinks and carbon neutrality.