Corrosion rate of carbonate tablet under diverse land use and lithology in the Dalongdong basin, Hunan

In order to discuss the differences of corrosion rates between the forestland and the grassland, tablets made of the Aoxi group dolomite(∈2a3) and the Bitiao group limestone(∈3b1) as well as the Guniutan group limestone（O2g）are used to test the soil CO2 concentration and organic content at 20 cm and 50 cm deep on soil profile in the Dalongdong basin, Hunan. It is concluded that, (1) the corrosion rates among the three tablets are quite different both under the forestland and the grassland at 20 cm and 50 cm deep on the soil profile with the ∈3b1g tablet the largest; (2) corrosion rates are affected obviously by lithology, the higher the CaO content the larger the corrosion rate, so the fewest the ∈2a3 tablet in CaO content(32.64 %), the smallest the corrosion rate of the ∈2a3 tablet; (3) the corrosion rate is larger under forestland than that under grassland, which proving the land type is of effect on corrosion rate. It will be benefit to karstification if the vegetation successes consequently towards forest from grass.