期刊名称：Journal of Environmental Science and Technology
印刷版ISSN：1994-7887
电子版ISSN：2077-2181
出版年度：2017
卷号：10
期号：4
页码：206-214
DOI：10.3923/jest.2017.206.214
出版社：Asian Network for Scientific Information
摘要：Background and Objective: SRI paddy field occasionally experiences aerobic soil conditions that emit complicated greenhouse gases due to biophysical processes. Understanding these emission patterns, as well as the amount, is important to determine the proper mitigation action to take. This study was carried out to produce a simple method to estimate CH4 and N2O using easily measure environmental parameters that might be used to simulate the mitigation of non-CO2 emissions. Materials and Methods: Two Artificial Neural Network (ANN) models were developed to estimate methane (CH4) and nitrous oxide (N2O) fluxes based on three selected variables. Based on the models, patterns of CH4 and N2O emissions in SRI paddy fields were presented in the form of a triangle graph that can be used to estimate emissions from the easily measured soil pH , soil moisture and air temperature. A sensitivity test (Spearmans correlation test) was used to statistically analyze data. Results: ANN models were developed to estimate emission fluxes based on three selected variables of soil pH , soil moisture and air temperature that could produce R2 0.96 and 0.82 for CH4 and N2O, respectively. CH4 emission in the SRI paddy field increased with air temperature but decreased when soil moisture decreased, while N2O emissions were mostly stable at all times regardless of changes in soil moisture and air temperature. In general, a higher soil pH produced higher CH4 and N2O emissions. The triangle graph shows that in SRI paddy field with soil pH , soil moisture and air temperature range 4.30-5.30, 0.354-0.524 m3 m3, 29.0-32.5°C, respectively; it could be a sink or emission of methane until more than 45 mg m2 day1 and be able to emit nitrous oxide to more than 6 μg m2 day1 . Conclusion: SRI paddy field can be emission source of CH4 and N2O. The graphs can be used to identify mitigation action that can be implemented to lower emissions by showing the set-point value of soil moisture. For example, in an air temperature of 29.4oC and soil pH condition of 4.8, to minimize the emission of CH4 and N2O, the soil moisture should be less than 0.418 m3 m3.
