Simulation of Methane Emission from Rice Paddy Fields in Vu Gia-Thu Bồn River Basin of Vietnam Using the DNDC Model: Field Validation and Sensitivity Analysis
Irrigated rice cultivation plays an important role in affecting atmospheric greenhouse gas concentrations. In recent years, extrapolation and simulation of impact of farming management on GHGs fluxes from field studies to a regional scale by models approach has been implementing. In this study...
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| Main Authors: | , , , , , , |
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| Format: | Working Paper |
| Language: | English |
| Published: |
ĐHQGHN
2015
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| Subjects: | |
| Online Access: | http://repository.vnu.edu.vn/handle/VNU_123/967 |
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| Institution: | Vietnam National University, Hanoi |
| Language: | English |
| Summary: | Irrigated rice cultivation plays an important role in affecting atmospheric greenhouse
gas concentrations. In recent years, extrapolation and simulation of impact of farming management
on GHGs fluxes from field studies to a regional scale by models approach has been implementing.
In this study, the DeNitrification & DeComposition (DNDC) model was validated to enhance its
capacity of predicting methane (CH4) emissions from typical irrigated rice-based system in Vu
Gia-Thu Bồn River Basin with two water management practices: Continuous Flooding and
Alternate Wetting-Drying.2 rice field experiments were conducted at delta lowland (Duy Xuyen
district) and midland (Dai Loc district), considered as typical regions along topography transect of
study areas. The observed flux data in conjunction with the local climate, soil and management
information were utilized to test a process based DNDC model, for its applicability for the rice-
based system. The model was further refined to simulate emissions of CH4 under the conditions
found in rice paddies of study area. The validated model was tested for its sensitivities to
variations in natural conditions including weather and soil properties and management alternatives.
The validation and sensitive test results indicated that (1) the modeled results of CH4 emissions
showed a fair agreement with observations although minor discrepancies existed across the sites
and treatments; (2) temperature factor changes had considerable impact on CH4 emissions; (3) soil
properties affected significantly on CH4 emissions; (4) varying management practices could
substantially affect CH4 flux from rice paddies. It was suggested that DNDC model is capable of
capturing the seasonal patterns as well a |
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