Refined estimates of organic carbon stocks in global Andisols

Andisols store a large amount of soil organic carbon (SOC) per area, yet their global SOC stocks remain uncertain. Here, we synthesized a global Andisol database of >2850 soil samples from 34 countries, covering a wide range of climatic and pedogenic environments. We estimated that the area-weighted global SOC stock (median depth: 107 cm) was 320 ± 46 Mg C ha−1 which is 50–70% higher than the most recent estimates for Andisols (top 1 m). The global SOC inventory in Andisols was estimated as 30.0 ± 4.2 Pg C, approximately 2% of the global SOC inventory. These refined estimates highlight the disproportionally high SOC storage of Andisols relative to their limited extent.