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Tuesday, August 11, 2009

Fighting climate change by reducing methane emissions from paddy fields of Jharkhand: a Blue Print

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Introduction
Jharkhand is a plateau land made up of mounds, rocks, hills and valleys. It is inhabited by a population of 2.69 crore out of which 2.09 crore population is found in rural areas. The rural economy is principally based on agriculture and forest produce. Paddy is the basic crop grown though out the year in low lands of valleys where natural water continues flowing most of the time. Farmers depend on rains for irrigating their crops but the run of rainwater is very high.It has been proved that carbon dioxide; methane and oxides of nitrogen (N2O) intensify the greenhouse effect contributing to the change of global climate. Natural sources of water are found here and there in the valleys of Jharkhand plateau. Water from these sources accumulates on deep surfaces and keeps on flowing up to long distances. The tribal people inhabiting these places grow paddy crops in these water logged zones through out the year. Due to unavailability of irrigation facilities in the plateau land of Jharkhand people often remain unable to grow other crops. The waste generated through agriculture and animal husbandry is thrown out in the open which decomposes to produce methane and other gases and invites pathogens of a number of infectious diseases potentially dangerous to the community health.

It has been proved that the roots of paddy harbor methanogenic bacteria that remain active even after the end of one cropping session. Since monocropping of paddy is continued through out the year in the same flooded fields, release of methane gas is continued from these fields. It has been observed that if paddy cultivation in such areas is shifted to uplands from the water logged areas, and watersheds are developed by constructing embankments to check the flow of water, pisciculture and lift irrigation practices can be adopted for raising the economy of farmers and irrigating the upland crops including paddy which is to be cultivated now just above the watershed line. The adoption of proper waste management practices and generation of bio-gas can reduce the disease burden and emission of gases that otherwise cause community health hazards and contribute to the climate change. Practices of raising Panchwati and adopting agro forestry and cultivation of vegetables on slopes with better irrigation facilities can further contribute to the income of the tribal people inhabiting the area.

Methodology

Following activities can be adopted to serve the purpose –
- Systems of sustainable agriculture
- Construction of watersheds, building up of water storage areas and construction of check dams
- Adoption of different applications of water storage like pisciculture in water sheds irrigation with the water from the water storage areas, Water purification and supply of safe drinking water.
- Generation of bio-gas from agriculture waste and supply of bio-gas to houses for lighting and cooking as it can reduce the risk of release of green house gases into the atmosphere and the pressure on forests for firewood.
- Poultry farming.

Following efforts can be taken up for a sustainable agriculture –
1. Paddy cultivation in water logged areas should be stopped immediately. Instead, paddy varieties demanding less water should be grown on upper parts by cutting field strips.
2. Adoption of drip irrigation or pipe irrigation systems in terraced fields – water should be lifted by water pumps installed in the watershed areas.
3. Cultivation of fodder crops along terraces so as to avoid overgrazing along hill slopes.
4. Adoption of mixed cropping practices on upper terraces.
5. Disposal of agriculture waste and domestic waste by composting and bio-gas generation on the community level – it can solve the problem of waste, spread of diseases, and release of gases including methane and oxides of nitrogen, and sulphur, the heat absorbing gases that contribute to the climate change.
6. Adoption of Panchwati and agro-forestry systems.
7. Use of fertilizers enriched with sulphur can help in controlling the propagation of methanogenic bacteria in paddy fields.

The process of Methane generation through paddy cultivation
It has been already reported that about 10 to 15 percent of the total methane emission comes alone from the paddy fields located in the waterlogged areas in valleys. The methanogenic bacteria found in the roots of paddy plants play important roles in the generation of methane. The methanogenic bacteria produce methane in less aerobic conditions available in water logged areas. These bacteria utilize carbon dioxide and water as sources of carbon and hydrogen. These bacteria are found especially in the waterlogged soils and marshes.
Dead roots of paddy plants and the exudates of paddy roots are most appropriate for the activities of the methanogens. First, these bacteria produce methane by decomposing organic substrates available in the soil. When flowering in paddy plants starts, the areas of parenchymatous tissues in paddy roots get increased. This is the time when methanogenic bacteria start the production of methane. They continue their activities even after harvesting of the crop.

Results/ Conclusion
The adoption of methods of less water demanding paddy varieties in non-flooded areas can help reduce emissions of methane, thus helping the global efforts to reduce climate change. The release of green house gases can also be checked by proper disposal of waste. The generation of bio-gas from the agriculture waste and animal waste can solve the problem of purchasing kerosene and going for firewood. It can not only save the money but can reduce the pressure on forests. Raising fodder crops can solve the problem of over grazing along slopes thus reducing the problem of landslides and erosion of soil along hill slopes. Pisciculture can certainly improve the economy of forest villages. Mixed cropping can improve the soil, and reduce the burden of plant diseases. Production of different types of food through sustainable agriculture practices can solve the problem of malnutrition and improve the reproductive health of tribal ladies.

References
1. Abao, E. B. Jr., Bronson, K. F., Wassmann, R. and Singh, U. (2000). Simultaneous records of methane and nitrous oxide emissions in rice-based cropping systems under rainfed conditions. Nutr. Cycl. Agroecosyst. 58: 131-139.
2. Chang, H. L. and Yang, S. S. (1997). Measurement of methane emission from soil. J. Chin. Agric. Chem. Soc. 35: 475-484.
3. Chao, C. C. (1997). Nitrous oxide emission from paddy field, upland, wetland, forest and slopeland in central and southern Taiwan and their effect factors. In: Research on Atmospheric Environments of Taiwan Area. pp. 173-194. Ed. by Lu, S. C., Liu, C. M. and Yang, S. S., Global Change Research Center and Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
4. Intergovernment Panel on Climate Change (IPCC). (1996). IPCC guidelines for National Greenhouse Gas Inventories, Vol. 2, Workbook, Vol. 3, Reference Manual, Geneva, Switzerland.
5. Lai, C. M. (1997). Nitrous oxide emissions from paddy, upland, wetland, forest soil and landfill in the northern Taiwan area and their affecting factors. In: Research on Atmospheric Environments of Taiwan Area. pp. 383-400. Ed. by Lu, S. C., Liu, C. M. and Yang, S. S., Global Change Research Center and Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.

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