Why is rice cultivation responsible for methane emissions?

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In summary: Different systems of growing rice have evolved to suit specific environments and socioeconomic conditions. In some cases, seeds are sown and the paddies flooded, though they may remain shallow. In other cases, where significant rise in water level occurs, rice may be grown in deeper water, up to 5 m! Most other grains, corn, wheat, rye, oats, millet, . . . would not grown in 5 m of water. Certain rices are uniquely suited for such conditions.
  • #1
jackson6612
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In many Asian countries, particularly India, rice is grown in a way where rice seeds are first sown in one field, and then the seedlings are taken out to be transformed to a water flooded field. I have not witnessed the plantation personally. Why don't they simply sow the seeds and get the full crop without any seedlings transfer?

The following videos illustrate what I'm saying:
http://www.youtube.com/watch?v=i8a0_yw-mg0&feature=related (watch between 1.07-2.10)

http://www.youtube.com/watch?v=ElYKKO82fpo&feature=related

In a Wikipedia article on rice I found this:

Environmental impacts

In many countries where rice is the main cereal crop, rice cultivation is responsible for most of the methane emissions. Rice requires slightly more water to produce than other grains.

As sea levels rise, rice will become more inclined to remain flooded for longer periods of time. Longer stays in water cuts the soil off from atmospheric oxygen and causes fermentation of organic matter in the soil. During the wet season, rice cannot hold the carbon in anaerobic conditions. The microbes in the soil convert the carbon into methane which is then released through the respiration of the rice plant or through diffusion of water.

The red part seems to suggest that whenever soil is covered with water, fermentation of organic matter starts taking place even when there is no crop, such as rice, involved. What do you say on this?

I couldn't understand the blue part. Please help me with it.
 
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One has to look at the specific area (fields and precipitation, and perhaps availability of irrigation).

Different systems of growing rice have evolved to suit specific environments and socioeconomic conditions.
http://www.plantcultures.org/plants/rice_production__trade_cultivation.html

In some cases, seeds are sown and the paddies flooded, though they may remain shallow.

In other cases, where significant rise in water level occurs, rice may be grown in deeper water, up to 5 m! Most other grains, corn, wheat, rye, oats, millet, . . . would not grown in 5 m of water. Certain rices are uniquely suited for such conditions.

http://www.rice-trade.com/semi-dry-upland-cultivation.html
http://www.rice-trade.com/wet-lowland-cultivation.html

I'm not sure what the concern is.

Of course, there are varieties of rice that can be grown in drier conditions. The use of ammonium sulfate can reduce methane production. Perhaps the local farmers use methods most suited to the local conditions and economics.

On the othe hand, The SYSTEM of RICE INTENSIFICATION may offer an improved system.
http://ciifad.cornell.edu/sri/
. . . and because paddy fields are not kept continuously flooded, there are water savings of 25 to 50%, a major benefit in many places. However, cessation of flooding means that increased weeding is required. If this is done with soil-aerating implements like a rotating hoe, this cost has a benefit of enhanced crop production.
 
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  • #3
Um... Algae, anyone?
 

1. Why is rice cultivation responsible for methane emissions?

Rice is a staple food for many countries and its cultivation involves flooding the paddy fields, creating an anaerobic environment. This anaerobic environment allows for the growth of methane-producing microorganisms, leading to the release of methane gas into the atmosphere.

2. How much methane is emitted from rice cultivation?

According to the Food and Agriculture Organization (FAO), rice cultivation is responsible for about 10% of global methane emissions. This translates to approximately 100 million tons of methane being released into the atmosphere each year.

3. Can rice cultivation be done without producing methane?

Yes, there are alternative methods of rice cultivation such as dryland farming or aerobic rice cultivation, which do not involve flooding the fields. These methods significantly reduce methane emissions, but they may not be suitable for all regions and may require different farming techniques.

4. How does methane contribute to climate change?

Methane is a potent greenhouse gas, with a global warming potential 28 times higher than that of carbon dioxide. When released into the atmosphere, methane traps heat and contributes to the greenhouse effect, leading to an increase in global temperatures and climate change.

5. How can we reduce methane emissions from rice cultivation?

There are several ways to reduce methane emissions from rice cultivation, such as using alternate farming methods, implementing water management techniques, and improving fertilizer and soil management practices. Additionally, research is ongoing to develop new rice varieties that produce less methane during cultivation.

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