Volume No. 12 Issue No.: 1 Page No.: 20-35 July-September 2017

 

FLUXES OF METHANE AND NITROUS OXIDE FROM RICE FIELDS OF UTTAR PRADESH AND BIHAR: ESTIMATION AND MITIGATION OPTIONS

 

Kumar Prabhat and Gupta N. C.

Department of Environment Management, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi (INDIA)

 

Received on : April 21, 2017

 

ABSTRACT

 

The continuous increase in the concentration of Greenhouse gases (GHGs) in the atmosphere is likely to cause climate change that can result in large changes in ecosystems. Agricultural rice fields are the important sources of methane (CH4) and nitrous oxide (N2O), the two GHGs produced by anaerobic decomposition of organic material in flooded field. Methane from the rice paddy field escapes to the atmosphere primarily by diffusive transport through the rice plants during the growing seasons. N2O is trapped in the soil long enough to get denitrified to N2 but during intermittent drying of the rice fields, N2O emission increases considerably. The quantification of GHGs from agricultural soils in India is uncertain due to varied soil types and climatic conditions. A field study was conducted using the manual closed chamber technique at 4 sites (Chachula (U.P), Meerapur(U.P), Kabar (U.P), and Rasalpur (Bihar)) in Indo-Gangetic region to continuously measure CH4 and N2O emissions from rice fields under various agricultural management schedules like water regimes (irrigated and rain fed), transplanting dates and nutritional amendments (fertilization application) in the year 2013. The typical day variation in the CH4 flux was observed after the rice heading stage, during which the daily time weighted mean CH4 flux was observed twice (09:00-10:00 and 14:00-15:00) time window (with 15 minutes interval). The results show that the value of CH4 flux (Kgha-1d-1) varied from 0.105 to 1.573 at Chachula and 0.217 to 1.586 at Meerapur whereas at Kabar it varied from 0.093 to 6.881 and 0.12 to1.511 at Rasalpur. The value of N2O flux (gha-1d-1) varied from 0.02 to 6.85 at Chachula and 0.2 to 7.7 at Meerapur while at Kabar it was 0.80 to 6.98 and 0.121 to 0.968 at Rasalpur respectively. The results clearly indicate that the integrative effects of water management and fertilizer application are imperative for mitigating greenhouse gas emissions in order to attenuate the greenhouse effect contributed by rice paddy fields.

 

Keywords : Close chamber, Greenhouse gas (GHG), Methane, Nitrous oxide, Seasonal variation, Treatment

 

 

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