Why is rice cultivation responsible for methane emissions?

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SUMMARY

Rice cultivation, particularly in Asian countries like India, significantly contributes to methane emissions due to its water-intensive growing methods. The anaerobic conditions created by flooding rice paddies lead to the fermentation of organic matter, resulting in methane release. The System of Rice Intensification (SRI) presents a more sustainable alternative by reducing water usage by 25-50% and minimizing methane emissions, although it requires increased weeding efforts. Understanding the environmental impacts and cultivation techniques is crucial for addressing methane emissions in rice production.

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  • Understanding of anaerobic fermentation processes
  • Familiarity with rice cultivation techniques, specifically the System of Rice Intensification (SRI)
  • Knowledge of environmental impacts of agriculture, particularly methane emissions
  • Awareness of water management practices in crop production
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  • Research the System of Rice Intensification (SRI) and its benefits
  • Explore methods to reduce methane emissions in rice cultivation, such as using ammonium sulfate
  • Investigate the environmental impacts of flooding in agriculture
  • Learn about alternative rice varieties suited for drier conditions
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Agricultural scientists, environmentalists, rice farmers, and policymakers focused on sustainable farming practices and reducing greenhouse gas emissions.

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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Um... Algae, anyone?
 

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