Studies on green house gas emissions from rice field in Rwanda
The overall objective of this research is to estimate the Green House Gases (GHGs) emissions in different time of the day and to bring out the time of maximum and minimum GHGs emissions from the rice field. An experiment was conducted to estimate the GHGs emission from the rice fields of Muvumba P-8. Gas collection chambers were installed in 9 plots to collect the greenhouse gases. The gas samples were analyzed in Gas Chromatography and converted its results in to usable form. There was marked difference in the mean CO2 gas emission among the plots. The overall mean of CO2 gas emission among the experimental plots was 1950521 μg m-2 h-1. CH4 gas emission was high at 9 am and the minimum is at 3 pm among the mean gas production. Maximum CH4 gas emission at 9 am is due to the fact that during night time rice plant takes more CH4 and release the same due to ambient temperature rise at 9 am. The minimum CH4 gas emission at 3 pm is due to the fact that rice plant released all its CH4 during day time around 9 am to 3 pm and there was less CH4 in the rice plant to release at 3 pm. The mean of N2O gas emission at 6 am, 9 am, 12 noon and 3 pm of all the experimental plots was found to be 960.86 μg m-2 h-1. The mean N2O gas emission at 9am was found to be 995.82μg m-2 h-1. The important conclusion from the study is that N2O gas emission at 6 am and 12 noon are behaving similarly with decreasing trend. It was also found that N2O gas emission at 9 am and 3 pm are behaving similarly with decreasing trend.
Keywords: Rice field, Green House Gases, emission, marshland