Abstract:
Abstract:Research on the effect of farm manure on carbonate rock dissolution is important for pedogenesis of carbonate rocks and source/sink of atmospheric CO2. In this study, dolomite and limestone tablets were buried in different depths of the soil profile in the karst area of Guiyang City, Guizhou Province and, at the same time, the dissolution amounts of tablets, soil CO2, soil pH, soil water content, soil minerals and chemical composition and soil water chemistry were monitored. The results show that manure application decreases the dissolution rate of carbonate rocks, with the dissolution amount of limestone and dolomite decreasing by 11.7%-116.9% (averagely 34.2%) and 25.0%-65.69% (averagely 39.45%), respectively, and the dissolution rate of limestone higher than that of dolomite under the same condition. Using these values, the decrease of the pedogenesis rate of carbonate rocks was estimated to be up to 35.77%-37.23% due to the application of manure. The results also suggest that manure accelerates the generation of soil CO2, and that soil CO2 concentration in the manure profile increases by 22.52%-198.87% (averagely 93.94%) and the CO2 flux increases by 67.64% as compared with the control profile. The data also indicate that manure decreases CO2 uptake by 25.50%-39.45% due to the dissolution of carbonate rocks in Guiyang City, and that it brings indirectly a 59.41%-62.72% counteraction to CO2 uptake in karst water of Guiyang area.