Abstract: With alkali aqua absorption method,CO₂ emission from the loess soil in Xi'an area was studied from Sep.1999 to Sep.2001.The results showed that the amount of CO₂ emission during the daytime was lower than that during the night,which tended to keep pace with the temperature change.The amount of CO₂ emission also changed with the seasons,which was the highest in summer,next in autumn,and lowest in winter.There was significantly positive correlation between the amount of CO₂ emission and temperature.The amount of CO₂ emission varied under different vegetation conditions,which was generally much higher on the bare ground than that of the others.Moreover,the emission of CO₂ in the soil was sensitive to the texture and structure of soil and CO₂ was emitted from loose layers more than solid ones.

Key words: Intersubspecific hybrid rice, Fertilization, Temperature, Model