Abstract:

Nitric oxide is important greenhouse gases and the farmland is the main discharge source of nitric oxide. Emission factor method, experiment extrapolation method, statistic model method and process-oriented model method were main methods to estimate the emission of nitrous oxide from cropland. Applying the above-mentioned method, the scientists estimated the emission of nitric oxide in the world, country and other region. The result showed that the emission gross of nitrous oxide in the world was between 1.2 Tg N and 4.2 Tg N. It is between 0.063 and 0.628 Tg N in China. Compared to other methods, process-oriented model was more accurate and it would play far more important role in estimating the nitrous emission. They would become priority for future studies to develop the forecast function and verify the model, definite N2O emission factor of N deposition, leaching and runoff, integrate the greenhouse gas reduction technology and do research on carbon trade on farmland greenhouse gas reduction.

Key words: farmland, nitric oxide, regional scale, model