云南省土壤有机碳储量估算及空间分布

根据云南省第二次土壤普查资料,采用土壤类型法估算了云南省主要土壤类型的有机碳(SOC)密度和储量,并对云南省土壤有机碳密度的空间分布差异和影响土壤有机碳储量的主要因子进行了分析。结果表明,云南省0-20 cm土层平均SOC密度为59.77 t/hm²,SOC储量为2.30×10⁹ t;0-100 cm土层平均SOC密度为159.95 t/hm²,SOC储量为6.15×10⁹ t,占全国储量的7.28%,占全球陆地生态系统SOC储量的0.41%;其中SOC储量占前4位的土壤类型为红壤、黄棕壤、赤红壤、棕壤,不同深度下4者之和约占云南省总储量的60%。在土壤有机碳密度空间分布上,SOC密度分布最高的区域为云南省西北部和东北部地区,其次是西部的横断山脉和东部的云南高原地区,而以紫色土为主的中北部地区SOC密度则最低。由于降雨量、温度、海拔和土地利用类型的共同影响,导致了区域内的SOC密度分布不均,其中降雨量、温度和海拔等自然因素是影响SOC密度分布的主要因子。

Spatial Distribution and Estimation of Soil Organic Carbon in Yunnan Province

According to the data from the second soil survey of Yunnan Province, the soil organic carbon(SOC) density and storage were estimated with soil type method; Meanwhile the spatial distribution of SOC density in Yunnan Province and the main factors on SOC density were analyzed. The results showed that the SOC density estimated in the 0-20 cm layer was 59.77 t/hm² and stock was about 2.30×10⁹ t; and the SOC density estimated in the 0-100 cm layer was 159.95 t/hm², its storage was about 6.15×10⁹ t accounting for 7.28% of the total in China and 0.41% of the global terrestrial ecosystems; the top four soil types in SOC storage were red soil, yellow-brown soil, lateritic red soil and brown soil totally taking up about 60% of that in Yunnan Province. The spatial distribution pattern of SOC density was the highest in Yunnan Province was in the northwest and northeast of Yunnan Province, followed by east of Hengduan Mountains and the western Yunnan plateau, and that of the purple soils in the north central area was the lowest. Otherwise, due to the impact of rainfall, temperature, elevation and land use types, the distribution of SOC density in the region was uneven. Furthermore the natural factors such as rainfall, temperature and elevation were the main factors affecting SOC density.