Carbonate rock dissolution rates in different landuses and their carbon sink effect

Research on karst processes is important for the determination of their carbon sink potential,as is research into terrestrial ecosystems in karst areas.Solutional denudation rates of soils from three karst spring watersheds supporting different land uses were studied.Solution rates showed a distinct pattern based on land use,with a generally higher rate being recorded in forest use soil.The mean values for tablet dissolution from the cultivated land,shrublands,secondary forest,grassland and primary forest were 4.02,7.0,40.0,20.0,63.5 t km-2 a-1 respectively.Changes in vegetation patterns could improve the size of karst carbon sinks;for example,in this study the carbon sink was 3 times higher in primary forest than in secondary forest soil and 9 times higher than under shrubland,equating to an increase from 5.71-7.02 to 24.86-26.17 t km-2 a-1 from cultivated land or shrub to secondary forest and to primary forest,respectively.