| The two anthropogenic induced N-trace gases, a powerful greenhouse gas N2O and an
important atmosphere pollution gas NO, which are getting more and more concerned. It is
reported that agricultural soil is the main sources of the two gases, which globally contribute
to 1.7-4.8 Tg N yr-1 and 1.6 Tg N yr-1, respectively. North China Plain is a seriously
intensive agriculture area of china, with 300,000 km2 which produces approximate
one-fourth of China’s total grain yield. The winter wheat - summer maize rotation (W-M),
winter wheat - scallion rotation (W-S), greenhouse vegetable (GV) are three typical
cultivation systems in this region. In the Recent 40 years, the conflicts between the demand of
high yield and excess fertilizer application have been getting increasingly outstanding.
Under such circumstances, we have conduced one and a half years to two years field
measurement to investigate the N2O and NO emissions. The mean accumulated N2O
emissions were 4.4, 4.4, 23.5 kg N ha-1 yr-1, emission factors were 0.65%, 0.52%,
0.90% for the W-M, W-S, and GV systems, respectively. The mean accumulated NO
emissions were 2.0, 0.7, 3.6 kg N ha-1 yr-1, emission factors were 0.3%, 0.07%,
0.14% for the relative systems, respectively. The emission patterns was typically
event driven pattern, except the GV system which mainly caused by basal fertilizer
application. Obviously, fertilizer application was the main driven factor. What’s more,
environment factors (e.g. WFPS, soil texture) also affected the two gases emissions.
The denitrification was the domain process during the entire growing period for
W-S and GV systems, however, referring to W-M system, both nitrification and
denitrification played an important role during the entire period. The nitrification inhibitors
application may be an available strategy to mitigate the two N- trace gases emissions. |