The turnover of soil inorganic carbon (SIC) is considered slowly and its role in carbon sequestration and climate change is limited. Therefore, the role of SIC in croplands to the global carbon cycle is rarely investigated. In recent years, more evidences have indicated that the turnover rate of SIC is much faster than was thought. This suggests that its roles in stabilizing soil fertility, global carbon pool, and regulating the concentration of carbon dioxide (CO2) in the atmosphere should not be ignored. Therefore, we have reviewed recent advances on SIC in croplands, paying special emphasis on the important role of SIC in sequestrating carbon and buffering soil pH. SIC loss in China induced by agricultural production, especially the application of nitrogen (N) fertilizers affects the health of croplands by accelerating soil acidification and increasing the risk of heavy metals pollution. Soils in the transition zones between the North and the South China (Qinling Huaihe River), brown soil and alluvial soil in the Shandong Peninsula, black soil and chernozem in Northeast China, have low carbonates and a vulnerable pool of SIC that is easily lost. Thus, we suggest that these regions should be designated as SIC loss vulnerable zones. For further studies, the following topics should be considered (i) understanding the fates of SIC and interactions of soil organic carbon-CO2- Ca-SIC in cropland induced by agricultural production, especially adding N fertilizers; (ii) SIC roles in carbon soil balance and cycle; and (iii) regular monitoring of the SIC content in the vulnerable zones. Also, for a sustainable reduction of SIC loss induced by soil acidification, the following measures should be considered: adequate application of N fertilizers, combining the application of N fertilizers with organic fertilizer and nitrification inhibitors and replacing the ammonium bearing fertilizers with nitrate fertilizer.