In order to obtain a high yield of vegetable,farmers now excessively apply chemical nitrogenous fertilizer,thus resulting in a drastic increase in nitrate accumulation and vegetable quality deteriorated.

,synthetic nitrogen fertilizer application,no-tillage and conservation tillage,irrigation,straw return,manuring and sewage sludge application) for net mitigation based on their soil carbon sequestration and impacts on the GHG leakage.