SOIL CARBON CONTENT AND CO2 FLUX IN EXPERIMENTAL REVEGETATION PLOTS, SOUTHERN ICELAND: IMPLICATIONS FOR SEQUESTRATION AND SOIL STABILIZATION
The carbon content in treated soils increased substantially during the initial eight years in plots for which the treatment included both fertilizer and seeding with grasses, concomitant with the increase in vegetative cover. In the following seven years, however, the soil carbon accumulation rates declined to negligible for most treatments and the carbon content in soils mainly remained constant. The only plots that displayed significant and consistent increase in soil carbon content were those seeded with lupine. These plots also exhibited substantially higher root respiration, as measured by soil CO2 flux (mean CO2soil = 2.90 μmol m-2 s-1). The lupine-treated plots are also distinctive in being the only plots displaying a positive correlation between soil carbon content and soil CO2 flux with r2 > 0.1. These results suggest that lupine may have utility in reclamation and stabilization of eroded land surfaces and in promoting carbon sequestration, but other ecological factors require consideration. This work has implications for development of long-term strategies for land reclamation and carbon sequestration in high latitude regions.