Methane emissions from rice fields and its mitigation options by vinal vishal chand


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Methane emissions from rice fields and its mitigation options by vinal vishal chand

  1. 1. 1 Name: Vinal Vishal Chand Id: 2012001280 PROGAMME: Bsc Agriculture (ii) 2013 Group: C ENV 701 ENVIRONMENTAL SCIENCE PRESENTATION
  3. 3. AIM The aim of this assignment was to find out about Methane emissions from rice fields and its mitigation options. 3
  4. 4. INTRODUCTION  The increasing demand of the growing population requires enhancement in the production of rice. This has a direct bearing on the global environment since the rice cultivation is one of the major contributors to the methane emissions.  As the rice cultivation is intensified with the current practices and technologies, the methane fluxes from paddy fields is substantially riseing.  Improved high yielding rice varieties together with efficient cultivation techniques will certainly contribute to the curtailment of the methane emission fluxes.  Irrigated rice farming in paddy fields is an important source of CH4.  Methane is a chemical compound with the chemical formula CH4. It is the simplest alkane and the main component of natural gas. The relative abundance of methane makes it an attractive fuel. 4
  5. 5.  Naturally occurring methane is mainly produced by the process of methanogenesis. This multistep process which is used by microorganisms as an energy source. The net reaction is: CO2 + 8 H+ + 8 e− → CH4 + 2 H2O  Methanogenesis is a form of anaerobic respiration used by organisms that occupy landfill, ruminants (e.g., cattle), and the guts of termites.  Rice agriculture is a big source of atmospheric methane, possibly the biggest of man-made methane sources. 5
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  7. 7. FLOODED RICE FIELDS In flooded rice field, anaerobic decomposition of organic material results in production of produces methane(CH4) This gas later escapes to the atmosphere primarily by diffusive transport through the rice plants during the growing season. From the wide sources of atmospheric CH4, rice paddy fields are considered one of the most important. 7
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  9. 9. METHANE PRODUCTION PROCESSES  Flooded rice fields are a significant source of atmospheric CH4.  The emission is the net result of opposing bacterial processes, production in anaerobic microenvironments, and consumption and oxidation in aerobic microenvironments, both of which can be found side by side in flooded rice soils  The major pathways of CH4 (methane) production in flooded soils are the reduction of CO2 (carbon dioxide) with H2 (hydrogen). CO2 + 4 H2 → CH4 + 2H2O 9
  10. 10. METHANOGENESIS It is simply the formation of methane by microbes This process is also called biomethanation Application of fertilizer, especially organic manure and submergence with deep water increased the population and methanogenic activities of methanogenic bacteria in rice soils. This process is estimated to contribute about 25% of the total budget of global methane emissions. 10
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  12. 12. FACTORS AFFECTING METHANE EMISSION  Land preparation  Seed preparation  Rice varieties  Fertilizer application  Water management or Water table  Harvesting and fallow period  Soil texture  Climate  Agricultural practices  Organic matter  Microorganisms 12
  13. 13. EFFECT OF METHANE ON ENVIRONMENT Climate Change Methane contributes to climate change. It is a potent contributor to global warming due to its ability to trap warm air. Methane have a major impact on world climate due to their contribution to the greenhouse effect. CO2 is not only factor but Methane also affects the degradation of the ozone layer. Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Methane is 23 times more potent than carbon dioxide in trapping heat in our atmosphere. 13
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  15. 15. Water Contamination Methane gas can seep into water supplies and contaminate wells or surface water. Deaths have been caused by exploding wells and by contaminated drinking water systems poisoned by this odorless, tasteless gas. 15
  16. 16. Emissions Methane emissions can seep up through the ground and cause problems for the environment and humans in particular The emissions don't just propose a danger for flammability but it also cause headaches and dizziness in humans as it replaces the oxygen. This can result in suffocation. 16
  17. 17. Oceanic Changes When water containg methane mixes with ocean it directly affects that climate and the life within that system. Vegetation Changes When methane is involved in the process that moves carbon into and out of vegetation zones that are climate and/or weather dependent, it forces a change and directly affects the vegetation growth and the life that requires that vegetation to exist within that system. 17
  18. 18. MITIGATION OPTIONS FOR METHANE water management  Altering water management, in particular promoting midseason aeration by short-term drainage, is one of the most promising strategies, although these practices may be limited to the rice paddy fields where the irrigation system is well prepared.  This method reduce methane production.  Shifting drainage time from vegetative period to reproductive period help reduce methane production and emission.  Shorten drainage day also help reduce methane emission. 18
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  20. 20. REDUCE USE OF ORGANIC MATTER  Improving organic matter management by promoting aerobic degradation through composting or incorporating into soil during off-season drained period.  Reduce the use of organic matter or organic manure in rice fields (wet lands).  Use inorganic fertilizer to increase the yields in wet lands. 20
  21. 21. DRY LAND RICE CULTIVATION Many rice varieties can be grown under much drier conditions than those traditionally grown, with big reductions on methane emission without any loss in yeild.  Additionally, there is the great potential for improved varieties of rice, able to produce a much larger crop per area of rice paddy and so allow for a cut in the area of rice paddies, without a cut in rice production. 21
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  23. 23. APPLICATION OF AMMONIUM SULPHATE The addition of compounds such as ammonium sulphate, which favours activity of other microbial groups over that of the methanogens. 23
  24. 24. A SOIL CONDITIONER  Is a product which is added to soil to improve the soil’s physical qualities, especially its ability to provide nutrition for plants.  It is category of soil Amendments which more often include a wide range of fertilizers and non-organic materials.  Soil conditioners can be used to improve poor soils, or to rebuild soils which have been damaged by improper management.  They can make poor soils more usable, and can be used to maintain soils in peak condition.  A wide variety of materials have been described as soil conditioners due to their ability to improve soil quality. Some examples include: bone meal, peat, coffee grounds, compost, manure, straw, vermiculite, sulfur, lime, blood meal, compost tea, hydroabsorbant polymers and sphagnum moss. 24
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  26. 26. CONCLUSION To conclude, emission of methane from rice fields are major problems in many country, it is mostly due to organic matter present the fields. However, mitigating CH4 emission from rice paddy fields can not be fully controlled. However it can be reduced. Some of the mitigation options are water management (which is the most important factor), soil amendments, organic matter management, different tillage, crop rotation, and cultivar selection. 26
  27. 27. REFERENCE  Seiler, W., A. Holzapfel-Pschorn, R. Conrad, and D. Scharffe. 1984. Methane emission from rice paddies.  Wang Zhaoqian. 1986. Rice based systems in subtropical China.   Holzapfel-Pschorn, A., R. Conrad, and W. Seiler. 1985. Production, oxidation and emission of methane in rice paddies. FEMS Microbiol. Ecol. 31: 343- 351 from-rice-paddy-fields.jpg?w=576  methane.html#ixzz2ee6XWOBj  methane.html#ixzz2ee80vRqp 27
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