Datta A, Santra S C, Adhya T K
Radio & Atmospheric Sciences Division, National Physical Laboratory, New Delhi 110 012, India.
J Environ Monit. 2011 Dec;13(12):3469-74. doi: 10.1039/c1em10478k. Epub 2011 Oct 28.
Temporal variations of the ambient mixing ratio of greenhouse gas (CH(4) and N(2)O) in a riparian rice-based agro-ecosystem of tropical region were studied during 2005-2006 in coastal Odisha. The endeavour was made with the hypothesis that the ambient mixing ratio of CH(4) and N(2)O depends on the changes in the flux of CH(4) and N(2)O from the rice fields in the riparian rice ecosystems. A higher ambient mixing ratio of CH(4) was recorded during the tillering to grain filling stages of the rice crop, during both dry and wet seasons. The higher ambient mixing ratio of CH(4) during the wet season may attribute to the higher CH(4) emission from the rice field. The average mixing ratio of CH(4) was recorded as 1.84 ± 0.05 ppmv and 1.85 ± 0.06 ppmv during 2005 and 2006, respectively. The ambient CH(4) mixing ratio was recorded negatively correlated with the average ambient temperature. The N(2)O mixing ratio ranged from 261.57 to 399.44 ppbv with an average of 330.57 ppbv during 2005. However, the average mixing ratio of N(2)O was recorded as 318.83 ± 20.00 ppbv during 2006. The N(2)O mixing ratio was recorded to be negatively correlated with rainfall and average ambient temperature. Significant negative correlation (r = -0.209) of N(2)O with sunshine hours may attribute to the photochemical break down of N(2)O. The temporal variation of N(2)O flux from the rice field does not affect the ambient mixing ratio of N(2)O in the same way as in the case of the ambient mixing ratio of CH(4). However, the higher mixing ratio of N(2)O during the fallow period of the post monsoon period may attribute to the N(2)O flux from soil. Results indicate that intensively cultivated coastal ecosystems can be a major source of ambient greenhouse gas.
2005 - 2006年期间，在奥里萨邦沿海地区，对热带地区河岸稻田农业生态系统中温室气体（CH₄和N₂O）的环境混合比的时间变化进行了研究。研究基于这样的假设：CH₄和N₂O的环境混合比取决于河岸稻田生态系统中稻田CH₄和N₂O通量的变化。在水稻作物的分蘖期至灌浆期，无论旱季还是雨季，都记录到较高的CH₄环境混合比。雨季CH₄环境混合比更高可能归因于稻田较高的CH₄排放。2005年和2006年期间，CH₄的平均混合比分别记录为1.84±0.05 ppmv和1.85±0.06 ppmv。记录到环境CH₄混合比与平均环境温度呈负相关。2005年，N₂O混合比在261.57至399.44 ppbv之间，平均为330.57 ppbv。然而，2006年N₂O的平均混合比记录为318.83±20.00 ppbv。记录到N₂O混合比与降雨量和平均环境温度呈负相关。N₂O与日照时数显著负相关（r = -0.209），这可能归因于N₂O的光化学分解。稻田N₂O通量的时间变化对N₂O环境混合比的影响与CH₄环境混合比的情况不同。然而，季风后休耕期较高的N₂O混合比可能归因于土壤中的N₂O通量。结果表明，集约化耕种的沿海生态系统可能是环境温室气体的主要来源。
