Machine learning-based analysis of distribution characteristics and sensitivity of soil organic carbon in typical soils of China

Soil organic carbon (SOC) is a vital component of the terrestrial ecosystem carbon cycle, reducing global warming and promoting plant nutrition, with its changes greatly impacting the global carbon balance and climate change. Recent studies show that different soil types have different abilities to store carbon under the influence of climate, topography, vegetation, and human activities. This study investigates five typical soil types in China (dark brown soil, aeolian soil, alpine meadow soil, red soil, and yellow soil), utilizing an open-access SOC density database and relevant literature to collect SOC density data from 2004 to 2023. Using the Random Forest (RF) model, the SOC density of the 0–20 cm soil layer from 2000 to 2023 was examined to reveal its changes over time and location and influencing factors. The study integrated SOC data from 2000 to 2023 with environmental factors, including climate, topography, vegetation, and soil properties. We found that SOC density across the five soil types ranks as follows: dark brown soil (8.75 kg/m 2 ) > alpine meadow soil (6.59 kg/m 2 ) > yellow soil (5.81 kg/m 2 ) > red soil (4.57 kg/m 2 ) > aeolian soil (2.47 kg/m 2 ). The carbon storage capacity of these soil types is influenced by factors like climate, vegetation, and soil properties. Furthermore, SHAP analysis revealed how each soil type responds differently to these factors. Based on these findings, we propose strategies for managing soil carbon storage. For different soil types, we recommend measures like restoring plant cover, using conservation tillage, and increasing tree planting to boost carbon storage and align with the dual carbon goals of China to tackle climate change. • A database of SOC for five typical soil types in China from 2015 to 2023(Manually collected). • Significant differences in carbon storage capacity among five typical soils. • The key factors influencing the carbon storage capacity of five typical soil types in China were quantified. • Revealed the threshold effects of key factors on the carbon sequestration capacity of five typical soil.