Abstract: Referring to the definition of agricultural field N₂O emission factor by the Intergovernmental Panel on Climate Change, the main controlling factors climate and cropping system were introduced to estimate the chemical fertilizer N-induced direct N₂O emission from China agricultural fields in 1991-2000, and a spatial inventory with 10 km×10 km resolution was developed by dint of GIS framework. The results indicated that there was an increasing trend in the annual direct N₂O emission, due to the increasing input of chemical fertilizer N. The mean annual emission in 1990s was estimated to be 204 Gg N₂O-N, ranging from 159 to 269 Gg N₂O-N, and the lowest and the highest emission occurred in 1992 and 1998, respectively. The uncertainty of the estimation was quantified to be about 23%. The spatial distribution of N₂O emission was characterized by higher flux in eastern China and lower flux in western China, which was mainly attributed to the application rate of chemical fertilizer N and precipitation.

Key words: Amblyseius cucumeris, Polyphagotarsonemus latus, Temperature, Developmental time