Rising atmospheric carbon dioxide concentration is a concern because of its potential for altering climate. Since the beginning of the Industrial Revolution in the 18th century, atmospheric CO2 has increased by more than 30%. The increase in fossil fuel burning and associated CO2 emissions is expected to continue for the foreseeable future, and a double or even tripling of the preindustrial concentration of atmospheric CO2 is possible by the end of the 21st century.
Some authors have thought agricultural soils could sequester a considerable carbon to slow the rise of the atmospheric CO2. In fact, this sequestering potential depends on initial soil content, climate and cultivation. The long-term experiments in North America have proved that arable lands have been changing from a C source to sink by conservation management, such as reduced- and no-till practice, manure use, rotation, and introducing cover crops. From the point of view of agricultural management, to keep the sustainable development and realize the carbon sequestration potential is crucial to both crop production and carbon mitigation. The contribution of China′s agricultural practice to atmospheric CO2 has been paid a great attention because China has a long history of agriculture to support one-fifth of global population.
In this study, based on domestic typical long-term field experiment data, experiential models were constructed to estimate the carbon sequestration status and potential of agricultural soil under different managements in China. In current situation, the carbon sequestration in agricultural soil of N fertilizer use, residue return, manure use and zero-tillage, were 40.51,23.89,35.83Tg•a-1 and 1.17Tg•a-1, respectively. The total carbon sequestration capacity was 1014 Tg•a-1, which was equal to 13.3% of the annual carbon emission from fossil fuel use in China. In the scenarios of increased N fertilizer use, popularization of residue return, manure use and zero-tillage, the carbon sequestration potential can reach 94.91, 42 .23, 41.38Tg•a-1 and 3.58 Tg•a-1, respectively. These management measures are very important to CO2 mitigation since the total carbon sequestration potential accounts for 23.9% of the annual carbon emission from fossil fuel use in China.