Correlationship of Soybean Plant to N_2O Emission from Soil-plant System in Field and Between N_2O Emission of Soybean Plant and Photosynthesis

To fractionate the contribution of plant to N2O emission from soil-plant system,the N2O emissions from soybean,soil and soil-plant system were measured by closed chamber method under field condition.In the meantime,some factors(photosynthesis and air temperature) affecting N2O emission were also studied.The results showed that during the daytime: there were one of N2O emission peak in the morning(10:30) and one valley in the afternoon(15:30) even absorbed the atmospheric N2O,from soybean plant under field conditions.Two peaks of N2O emissions from soybean plant occurred at late June and the middle August stages,respectively.The emission of N2O from soybean accounted for 25%～57% of the total N2O emissions from soil-soybean system during the period of time from late June to the end of August.It was found that there was a certain correlationship between N2O emission of soybean plant,soybean-soil system and air temperature(r2=0.4954 and 0.5357).There was a certain correlationship between N2O emission of soybean plant and photosynthesis r2=0.5944)