Increased Sequestration of Organic Carbon in Soil by Hydrophobic Protection

 The impact of soil organic carbon dynamics on the global carbon cycle is still largely uncertain despite studies of agricultural activities and control emissions of greenhouse gases to the earth's atmosphere. Improved knowledge of organic matter dynamics should lead to reduction in CO₂ emissions. We used stable carbon isotope analysis to detect small changes in organic carbon storage and turnover upon soil treatments with a ¹³C-labeled aliphatic alcohol previously partitioned into soluble humic substances of varying hydrophobicity. We found that labeled organic carbon is increasingly protected from mineralization with increased hydrophobic character of humic matter. The stabilization of organic carbon by hydrophobic protection significantly reduced decomposition during incubation time in soil. Hydrophobic protection can become an useful tool to limit decomposition of fresh organic matter in soil and thus reduce CO₂ emission from agricultural soils on a global scale. Received: 1 March 1999 / Accepted in revised form: 16 June 1999