CH4 Emission Flux Model in Rice Growing Season in Cold Region Under Water Saving Irrigation Mode

Lihong Yu , Mengxue Wang

CH4 Emission Flux Model in Rice Growing Season in Cold Region Under Water Saving Irrigation Mode

2020

Lihong Yu , Mengxue Wang

Rice paddies have been identified as major methane (CH4) source induced by human activities. Water management is an important factor affecting CH4 emission during the rice growing season, and the water depth in a rice field directly affects the production, oxidation, and transfer. Field experiments on irrigation management are generally conducted under three modes: control irrigation, intermittent irrigation, and long-term flood irrigation. Static opaque chamber gas chromatographic method was adopted in this work for in situ observations of CH4 emission flux in a field in the rice growing season in a cold region of China. Test data from 2016 was adopted to establish the single factor and interaction types of the CH4 emission flux estimation model for the rice growing season under different water management methods, and the data from 2017 was used for model inspection. The estimation models were based on NO3-N in soil and soil temperature, 10 cm under the soil surface. All models passed the significance test for significance levels of P<0.01. The average forecast error of the model is 13.53-24.78%, and the coefficient of determination Radj2 is between 0.399-0.675. The calculated values of the model are consistent with the measured values. The model established in this research can be used for estimation of CH4 emission in the rice growing season in cold regions of China for different water-saving irrigation modes.

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