Development of Soil Organic Carbon Reference for Advancing National Greenhouse Gas Inventory

Abstract

Soil Organic Carbon (SOC) plays an important role in the global carbon cycle and climate change. The carbon stored in soil is estimated to be 2-3 times of the atmosphere's carbon. In this study, we estimated SOC storage at national scale and generated country specific factor related Soil Organic Carbon reference (SOCref) alternative IPCC's default value. The soil data was collected about 5,052 pedons and 21,170 layers by Korean Rural Development Adminstration (RDA) from 1970 to 1999. Because of lacking of bulk density (BD), we generated BD using Adam's equation ( 1999) and used to equal-area smoothing spline depth function for calculating carbon density. The analytical results showed that the total amount of soil organic carbon in South Korea was about 395 megaton, and that the average carbon density was about 45.7 ton C ha -1 . The average and confidence interval of carbon density according to IPCC classification's 4 categories ; Sandy, Low Activity Clay (LAC), High Activity Clay (HAC), and Volcanic soil type were 19.7±4.5 Mg C ha -1 , 37.6±2.1, 39.1±16.2, and 127.8±16.4 respectively. We also compared the SOCref to 2006 IPCC Guideline's default value. The results showed SOCref of Sandy, LAC soil type and HAC was lower, and Volcanic soil type was higher than IPCC's default value. This study presents basic data and an analysis method for carbon stock and storage study and also provides scientific support for policy making efforts to control CO 2 emission in South Korea.