Characterization of carbon dioxide (CO₂) fluxes was investigated in tropical lowland flooded rice ecology using open path eddy covariance (EC) technique during dry season of 2009–2010. Select environmental variables like air and soil temperatures, soil moisture, net radiation, photosynthetically active radiation, vapour pressure deficit and soil heat flux were monitored throughout the season and correlated with half hourly CO₂ fluxes. The study was conducted to gain insight of environmental impact in terms of carbon (C) budget in a submerged soil of tropical region planted to rice. Total C budget integrated over dry season expressed in terms of net ecosystem CO₂ exchange (NEE) was − 392 g C m⁻², while the gross primary production (GPP) and ecosystem respiration (RE) were 731 and 339 g C m⁻², respectively. Seasonal daily mean NEE, GPP and RE were − 3.73, 6.96 and 3.23 g C m⁻² d⁻¹, respectively. The ratio of RE/GPP in flooded rice field was 0.46. The NEE was negative during daytime and positive during nighttime, i.e. rice paddy ecosystem acted as a CO₂ sink and source during daytime and night hours, respectively. Lowest negative NEE was found during heading to flowering stage (− 26.93 µmol CO₂ m⁻² s⁻¹) of crop growth due to estimated highest values of GPP (32.34 µmol CO₂ m⁻² s⁻¹) and RE (5.42 µmol CO₂ m⁻² s⁻¹). On seasonal basis flooded rice ecology behaved as net sink for CO₂. This was attributed to higher photosynthetic capacity of lowland rice to convert atmospheric C into organic compounds and slow organic matter decomposition in flooded soils.

使用开放路径涡动协方差（EC）技术在2009-2010年旱季期间对热带低地淹没水稻生态系统中的二氧化碳（CO ₂）通量进行了表征。在整个季节中监测选定的环境变量，例如空气和土壤温度，土壤湿度，净辐射，光合有效辐射，蒸气压赤字和土壤热通量，并将其与半小时CO ₂通量相关联。进行这项研究的目的是从种植稻米的热带地区淹没土壤中的碳（C）预算方面获得对环境影响的见解。以净生态系统CO ₂交换（NEE）表示的干旱季节的总碳预算为-392 g C m ^-2，而初级生产总值（GPP）和生态系统呼吸（RE）分别为731和339 g C m ^-2。季节性每日平均NEE，GPP和RE分别为-3.73、6.96和3.23 g C m ^-2 d ^-1。淹水稻田中RE / GPP的比例为0.46。NEE在白天为负，而在夜间为正，即稻田生态系统分别在白天和夜间充当CO _2的吸收和排放源。由于估计的GPP最高值（32.34 µmol CO ₂ m ^-2  s ^-1），在作物生长的开花期（-26.93 µmol CO ₂ m ^-2  s ^-1）期间发现最低的负NEE 。）和RE（5.42 µmol CO ₂ m ^-2  s ^-1）。在季节性基础上，淹水水稻生态系统表现为CO _2的净汇。这归因于低陆稻米具有更高的光合作用能力，可将大气中的C转化为有机化合物，并在水淹土壤中减缓了有机物的分解。