Agriculture Practices on GHG Production: Adaptation and Mitigation of GHG Emission from Agriculture Sector R. Gowthami 1*, K. V. Raghavendra 2 and R. Shashank 3 1, 2 Ph. D. Student, AC & RI, Madurai, Tamil Nadu Agricultural University, Coimbatore 3 M. Sc. Student, Govt. Science College, Bengaluru *Email of corresponding author: gowthamir111@gmail.com Kheti Volume -2, Issue-4 (October-December), 2014 Available online at www.popularkheti.info 2014 popularkheti.info ISSN: 2321-0001 Climate change due to increasing concentrations of greenhouse gases (GHGs) has emerged as a serious global environmental issue. The intergovernmental Panel on Climate Change included six gases as green house gases viz., carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perflurocarbons and sulphur hexafluoride. In turn, the agricultural sector also contributes to emissions. Agriculture contributes 50% of global methane (CH4) emissions, 60% of global nitrous oxide (N ² O) emissions and is a net contributor of 10-12% of total anthropogenic greenhouse gas emissions. There are several mitigation and adaptation strategies are present to minimise the GHG emission from agriculture sector and also to protect the environment from the adverse effects of climate change. Introduction Climate change due to increasing concentrations of greenhouse gases (GHGs) has emerged as a serious global environmental issue. The impact of human activities on climatic system is indisputable. Industrialization, urbanization, population growth and exploitations of natural resources will have an impact on the environment. The intergovernmental Panel on Climate Change included six gases as green house gases viz., carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perflurocarbons and sulphur hexafluoride. The first three gases in the atmosphere are produced as a result of agriculture and livestock activities. The continued increase in the concentration of GHGs in the atmosphere will lead to climate change affecting humanity, flora and fauna. In turn, the agricultural sector also contributes to emissions. Agriculture contributes 50% of global methane (CH4) emissions, 60% of global nitrous oxide (N ² O) emissions and is a net contributor of 10-12% of total anthropogenic greenhouse gas emissions. Sources of Green House Gases The major volume of carbon dioxide released in atmosphere is caused by deforestation and burning of fossil fuel. Methane emission occurs in the atmosphere through human related activities as well as through natural activities. Methane and nitrous oxide are the two most important GHGs chiefly originating from agriculture sector. The contribution of methane and nitrous oxide has been found to be about 15 and 5%, respectively in the enhanced greenhouse Kheti ISSN: 2321-0001 149
effect. According to IPCC (2007) agriculture and allied sector contribute about 50 and 70% to the total anthropogenic eissions of methane and nitrous oxide global scale. 1. Methane (CH 4 ) Although atmospheric methane concentration (1774 ppb) is very low as compared to CO 2 (379 ppm), it contributes around 21% of global warming alone. During the last few years its concentration has been increasing on an average at the rate of about 0.8% per year. The principal sources of methane from agriculture are enteric fermentation in ruminants, flooded rice fields and anaerobic animal waste processing. Methane is the second key greenhouse gas (GHG) and enteric fermentation in livestock is one of the largest sources of methane emission, producing 15-20 % of the total anthropogenic methane. Methane production by enteric fermentation in the rumen accounts for the 2-12% loss of gross energy and consequently influence performance of ruminants. Livestock contribute both directly and indirectly to climate change through the emissions of greenhouse gases such as carbon dioxide, methane and nitrous oxide. Green House Gases Methane Nitrous oxide Carbon di Oxide Sources Rice cultivation Live stock production 1. Direct soil emissions Synthetic fertilizer use Animal waste Biological N 2 fixation Crop residue Cultivated histosols Crop residue burning Forest fires Deforestation Organic matter decomposition Farm machinery Emission associated with tillage practices 2. Indirect emission Atmospheric deposition Nitrogen leaching and runoff Animal waste manangement systems Fertlilizer and transport application Emissions from mineral extraction Emission from production of pesticides Emission from pumping water Emission during harvesting and threshing of agricultural produce 2. Nitrous oxide It has been estimated that 90% of the NO 2 emissions come from soils but there is considerable uncertainty in the global budget nitrous oxide and the contribution of the various sources. Nitrous oxide is emitted into atmosphere as a result of biomass burning and nitrification and denitrification in processes in soils. Agricultural management practices and prevailing weather conditions are important in N 2 O production and emissions. The preceding cropping practices have a far-lasting effect on N 2 O emissions during the following cropping season. Weather condition can change soil temperature and moisture that are important factors influencing soil N 2 O emission. Temperature controls several soil processes such as organic matter decomposition, denitrification and nitrification. High soil water content often restricts gas diffusion and limits oxygen supply, which can cause a temporary accumulation of N 2 O with possible considerable emissions. Agricultural management practices, e.g., N application, ploughing practices and crop rotation regime determine the grain yield and plant biomass. About Kheti ISSN: 2321-0001 150
5% of the overall nitrous oxide emissions in the country come from livestock excretions. A large proportion of cattle herd is kept on low quality pasture in an extensive system and most of the excreta produced are dispersed in land. A large share of cattle dung is gathered for fuel, about 0.7% of the nitrogen in dung is released as nitrous oxide after burning. 3. Carbon dioxide It is estimated that livestock contributes 18% of the CO 2 equilvalent to green house gases, which is of serious concern. Carbon dioxide enters the atmosphere through the burning of fossil fuels, solid waste, trees and wood products and also as a result of other chemical reactions. Globally, livestock sector contributes 18 percent (7.1 billion tonnes CO 2 equivalent) of global greenhouse gas emissions (IPCC, 2007). Although it accounts for only nine percent of global CO 2, it generates 65 percent of human-related nitrous oxide (N 2 O) and 35 percent of methane (CH 4 ), which has 296 times and 23 times the Global Warming Potential (GWP) of CO 2 respectively (IPCC, 2007). Mitigation and Adaptation Strategies to Minimize GHG Production Mitigation Strategies Agriculture sector contributes significantly towards greenhouse gas emission to the atmosphere. Many methods have been tested to reduce the emission of GHGs from agricultural field. Some important methods for minimizing the GHG emission are given below. 1) Site specific nutrient management techniques: Site specific nutrient management techniques includes site specific quantitative knowledge of crop nutrient managements, nutrient supply through organic manures and biofertilizers, use of proper fertilizer, suitable method of fertilizer application. Application of fertilizers according to the requirements of the particular crop will increases the fertilizer use efficiency. Hence there is need to apply based on the nutrient requirement of the crop, this reduces the emission of GHG particularly nitrous oxide if the nitrogen is added according to the requirement. Method of application is also important method of mitigation and it will vary for each crop and fertilizer also. 2) Tillage practices management: It is the physical manipulation of soil with tools and implements to result in good tilth for better germination and subsequent growth of crops. Optimization in tillage practices i.e., minimum tillage, bed planting also help in mitigation cof nitrous oxide and methane from soil as compared to manual planting. 3) Use of nitrification inhibitors: During nitrification and denitrification process N 2 O is formed by the activity of soil microbes. Use of specific microbial inhibitors will inhibit or slow down the N 2 O emission and acts as a potential mitigation strategy for protecting our environment from the harmful effects of N 2 O increase in environment 4) Proper water management techniques: There are several sources for GHG emission from the agriculture sector, out of all these sources water management practices plays a crucial role. It has been found that water regime in irrigated rice fields with higher water percolation and poor water supply results into multiple aeration, which has direct effect on GHG emission. Kheti ISSN: 2321-0001 151
5) Selection of suitable varieties: The emission of GHG especially methane and nitrous oxide can be mitigated by choosing the appropriate variety that can help in reducing the adverse effects of GHG on climate. 6) Carbon capture techniques: a) Restoration of degraded lands: Restoration of degraded land have greatest potential to sequest carbon in soil. Agroforestry activities can also increase farmers agricultural productivity and income security be improving soil fertility, reducing vulnerability to drought. b) Afforestation and Reforestation: The process of growing trees to protect the environment from harmful gases is known as afforestation. c) Soil water conservation d) Soil carbon sequestration e) Crop residue management 7) Reduce crop residue burning: 8) Enteric fermentation mitigation strategies: There are different methods are present to minimize the GHG emission from enteric fermentation. Strategy Management strategies Nutritional strategies Rumen manipulations Advance strategies Different methods Reducing number of animals Improved nutrition Improved gender selection Improved grassland management High forage quality diets Diet modification Use of Propionate enhancer Biological control using predators for methanogens Genomics to change microbes and their pathways Genetic engineering Immunization Bacteriophagee Adaptation strategies in agriculture to minimize GHG production 1) Agrobiodiversity: biodiversity in all its components increases resilience to changing environmental conditions and stresses. Genetically diverse populations and species rich ecosystems have greater potential to adapt climate change. Wild species have more adaptation capacity to both biotic and abiotic stresses than the cultivated varieties. Hence transfer of these characters can be done by using different tools. 2) Agricultural insurances: Agricultural insurances are expected to offer a valuable contribution to adaptation. Agricultural insurances is one method by which farmers can stabilize farm income but also helps the farmers to initiate production activity. 3) Land use management: land use management can be done by adopting several practices like seasonal change and sowing dates, use of different species, forest fire management, promotion of agrobiodiversity, mixed farming, silviculture etc. Kheti ISSN: 2321-0001 152
4) Drought management: Drought is one of the serious problems facing due to the changes in climate. There are several strategies to adapt crop varieties to drought conditions like avoidance and tolerance mechanism, growing drought resistant cultivars, soil water conservation methods etc. 5) Fertilizer and nutrient management 6) Replacing globalisation with localisation Conclusion In present day situation entire world is experiencing the adverse effects of global warming due to greenhouse gas emission and therefore more serious efforts are required to reduce the concentration of greenhouse gases in the environment. The intergovernmental Panel on Climate Change included six gases as green house gases viz., carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perflurocarbons and sulphur hexafluoride. The first three gases in the atmosphere are produced as a result of agriculture and livestock activities. References Bharadwaj Venkatesh, Mishra AK, Singh SK, Pachauri SP and Singh PP. 2009. Selection of suitable planting method and nutrient management techniques for reducing methane flux from rice fields. Paper presented at International Conference on Challenges and opportunities in Agrometeorology, New Delhi. Bhattachsrya S and Mitra AP. 1998. Greenhouse gas emission in India for the base year 1990. Global Change, 11: 30-39. Bisht N, Bharadwaj Venkatesh, Mishra AK, Pachauri SP and Singh PP. 2008. Methane flux from rice fields as influenced by organic amendments and inorganic fertilizerd. Proceedings of workshop on Appropriate Technologies for Hills. GBPUA, Pantnagar. IPCC 2007. Climate change the physical science basis, summary for policymakers, inter - governmental panel on climate change. Kheti ISSN: 2321-0001 153