Rice agriculture is the biggest man made methane source. The warm water logged soil provides an ideal condition for methanogenesis and only a few amount of methane is oxidized by methanotrophs and the vast majority is released in to the atmosphere. A major source of methane emission is the decomposition of fertilizers and crop residue in flooded rice cultivation. Methane in rice paddies is produced by microscopic organisms that respire carbon dioxide. More CO2 increases the growth rate of rice plant and this promotes the micro-organism to pump up their metabolism. And all this increases the methane production by rice field. It is estimated that rice cultivation is responsible for 50 to 100 million tones of methane per year. And with the increasing demand of rice as food crop every year, the rate of methane emission is increasing at much higher rate. The fact that rice is the world?s second largest crop and an significant source of methane emission, and  that methane is more powerful GHG than carbon dioxide, shows the degradation that it has been causing to environment.

Rice can never possibly be replaced by any other crop. So, proper acts to mitigate such effects of rice cultivation should be undertaken by us. Though, zero emission may not be possible but many practices have proved to be much effective in reducing the emission by significant amount. Some of the most promising ways are listed below:

1) System of Rice Intensification (SRI): SRI is a scientifically proven alternative rice growing method that is currently adopted only in about 28 countries. It simply focus on avoiding flooding of rice field but maintains soil moisture keeping it well drained and aerated that facilitates aerobic respiration, thereby reducing the formation of methane. It allows alternate drying and wetting of rice field, preventing complete submergence in water as practiced in traditional method. Researches have shown that 1 million rice field converted into SRI method for 5 year reduces methane emission by about 441,000 ton CO2 annually. Other key bebefits of SRI are:

a) Use of organic fertilizer instead of chemical fertilizer and avoiding the use of harmful chemical pesticide and insecticide.

b) Improves food security by increasing yield by about 82% and also increases farmer income.

c) Avoids irrigation related conflicts that are common in rice growing seasons.

2) Use of heat tolerant rice varieties that can be grown in much drier conditions than the traditional one.

3) Addition of compounds like ammonium sulphate that favours activity of other microbial groups over methanogens.

4) Mid season drying of rice field has also proved to be beneficial.