Soil organic carbon in the Sanjiang Plain of China: storage, distribution and controlling factors

[摘要] The accurate estimation of soil organic carbon (SOC) storage and determination ofits pattern-controlling factors is critical to understanding the ecosystemcarbon cycle and ensuring ecological security. The Sanjiang Plain, animportant grain production base in China, is typical of ecosystems, yet itsSOC storage and pattern has not been fully investigated because of insufficientsoil investigation. In this study, 419 soil samples obtained in 2012 for eachof the three soil depth ranges 0–30, 30–60, and 60–100 cm and ageostatistical method are used to estimate the total SOC storage and density(SOCD) of this region. The results give rise to 2.32 Pg C for the SOCstorage and 21.20 kg m⁻² for SOCD, which is higher than the mean valuefor the whole country. The SOCD shows notable changes in lateral and verticaldistribution. In addition, vegetation, climate, and soil texture, as well asagricultural activities, are demonstrated to have remarkable impacts on thevariation in SOCD of this region. Soil texture has stronger impacts on thedistribution of SOCD than climate in the Sanjiang Plain. Specifically, claycontent can explain the largest proportion of the SOC variations (21.2%in the top 30 cm) and is the most dominant environmental controlling factor.Additionally, the effects of both climate and soil texture on SOCD show a weakening with increasing soil layer depth. This study indicates thatreducing the loss of SOC requires effective conservation and restorationefforts of wetlands and forestlands, as well as sensible fertilization. The resultsfrom this study provide the most up-to-date knowledge on the storage and patternof SOC in the Sanjiang Plain and have important implications for thedetermination of ecosystem carbon budgets and understanding ecosystemservices.

[学科分类] 地球化学与岩石