A Preliminary Model for Methane Emission from Rice Fields
稻田甲烷排放的初级模式

A preliminary numerical model is built to describe the production and subsequent transport of methane in rice fields. The model embodies the effect of weather condition and acme field managements on the methane emission rate. The model includes three major segments which are highly interactive in nature; growth of rice, decomposition of soil organic matter and production, transportation and emission of methane. Explicit equations for modeling each segment mentioned above are given. The main results are:1) The seasonal variation of methane emission obtained from t.he model quite agrees with that from field experiments. The difference of seasonal average methane emission rate between modeling value and experiment data is about 10%. 2) During the whole rice growing period, the seasonal variation of transport abilitity of rice plant in model calculation is similiar to the experiment data. It increases with time and reaches maximum during the stage in the middle of heading. 3) The content of soil organic matter is one of the major factors which determines methane average emission rate, and temperature controls the trend of methane emission from rice fields.