Abstract: Fertilization is exerting a significant effect on the physical and chemical characteristics of soil and chemical weathering dynamics of carbonate, and then on carbon cycle system. In this study, three columns (control column, cattle dung column and compound fertilizer column) with carbonate rock tablets in their bottoms were established to explore the impact of cattle dung and compound fertilizer addition on the dissolution of carbonate rock tablets according to the hydro-chemical analysis on the leachates of the three columns and the comparison of the dissolution amount of carbonate rock tablets. Here, the results showed that the transitory increases of HCO3-, Cl-, NH4+, COD, K+, Ca2+, Mg2+, Na+, NO3-, free CO2, SO42- and HPO42- in the leachate are brought by cattle dung addition, and an evident impact of cattle dung addition on the dissolution of carbonate rock tablets cannot be detected in this study. The indistinct increases of NH4+, free CO2, HCO3-, HPO42- and COD in the leachate can be observed after the compound fertilizer addition, whilst the pH decrease, which was mainly attributed to the release of protons from the nitrification reaction. The dissolution amount of limestone and dolomite tablets decreased due to the compound fertilizer application, where the dissolution amount of both limestone and dolomite were 0.0008 g in the control column, however, that of limestone and dolomite was 0.0034 g and 0.0015 g in the compound fertilizer column, respectively. Furthermore, the calculated results of the saturation index of calcite and dolomite by using Phreeqci showed that the saturation index of calcite and dolomite decreased after the compound fertilizer addition and had little change after the cattle dung addition. Thus, it should be noted that the impact of compound fertilizer especially ammonium fertilizer on the budget of CO2 sink cannot be omitted both the regional and global scale.
Key words: cattle dung； compound fertilizer； carbonate rock tablet； dissolution； column experiment
EARTH AND ENVIRONMENT Vol. 39, No.4, Tot No.286, 2011, Page 597
