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Challenges and opportunities for carbon sequestration in grassland systemsA Technical Report on Grassland Management and Climate Change MitigationS AmericaN AmericaPacific(development)EuropeAsia (incl. FSU)AfricaS AmericaN AmericaPacific(development)EuropeAsia (incl. FSU)Africa0 2 4 6 8 10 12% of total grassland/savannah area0 2 4 6 8 10 12% of total shrubland areacroplandpastureFigure 1: Percentage of native grassland/savannah and shrubland that has beenconverted to cropland and pastureSource: Ramankutty et al., 2008The development challenges faced by the populations of the world’sdry grasslands systems vividly illustrate the tightening linkage betweenecosystem services and enhanced human well-being: 2 billion peopleinhabit dryland regions, yet dryland regions have only 8 percent of theworld’s renewable water supply. This means that people have access towater that meets only two-thirds of the minimum per capita requirements,population growth rates are faster in drylands than anywhere else, butproduction potential is lower than anywhere else. Traditional socioecologicalsystems have evolved to cope with climatic and economicuncertainty, but population and economic pressures are increasinglytaxing traditional systems (Verstraete, Scholes and Stafford Smith, 2009).Primary production in rangelands is relatively low, varies substantiallyfrom place to place, and is strongly limited by precipitation (Le Houerou,1984). Even where rainfall is high (some grassland areas receive as muchas 900 mm of precipitation per year), almost all of the precipitation fallsduring distinct rainy seasons and evapotranspiration demands exceedprecipitation during most of the year. Moreover, precipitation, and thusproduction, varies considerably from year to year, with coefficients ofvariation averaging 33 percent, and as high as 60 percent in some of thedrier areas (Ellis and Galvin, 1994). Grasslands are thus highly vulnerableto climate change (Thornton et al., 2007; 2009).4Integrated Crop Management
ackgroundGrasslands are intensively used anddegradation is widespreadA large part of the world’s grasslands is under pressure to producemore livestock by grazing more intensively, particularly in Africa’srangelands, which are vulnerable to climate change and are expectednonetheless to supply most of the beef and milk requirements in Africa(Reid et al., 2004). As a result of past practices, 7.5 percent of theworld’s grasslands have been degraded by overgrazing (Oldeman, 1994).Previous research has documented that improved grazing managementcould lead to greater forage production, more efficient use of landresources, and enhanced profitability and rehabilitation of degradedlands (Oldeman, 1994). The strong bond between ecosystem services andhuman well-being in the world’s dryland systems demonstrates the needfor a new, integrated approach to diagnosing and addressing sustainabledevelopment priorities, including maintenance of the supply of criticalecosystem services.One of the reasons for the intensive use of grasslands is the high naturalsoil fertility. Grasslands characteristically have high inherent soil organicmatter content, averaging 333 Mg 1 ha -1 (Schlesinger, 1977). Soil organicmatter – an important source of plant nutrients – influences the fateof organic residues and inorganic fertilizers, increases soil aggregation,which can limit soil erosion, and also increases action exchange and waterholding capacities (Miller and Donahue, 1990; Kononova, 1966; Allison,1973; Tate, 1987). It is a key regulator of grassland ecosystem processes.Thus, a prime underlying goal of sustainable management of grasslandecosystems is to maintain high levels of soil organic matter and soilcarbon stocks.Portions of the grasslands on every continent have been degradedowing to human activities, with about 7.5 percent of grassland havingbeen degraded because of overgrazing (Oldeman, 1994). More recently,the Land Degradation Assessment in Drylands (LADA) concluded thatabout 16 percent of rangelands are currently undergoing degradation andthat rangelands comprise 20–25 percent of the total land area currently1mega gramsVol. 9–20105
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Page 4 and 5: The designations employed and the p
Page 7: Executive SummaryImplementing grass
Page 11: Chapter 2BackgroundGrasslands cover
Page 15 and 16: Chapter 3OpportunitiesCarbon seques
Page 17 and 18: opportunitiesStephens et al., 2007)
Page 19 and 20: opportunitiesMany management techni
Page 21 and 22: opportunities1.31.21.11.00.90.8nomi
Page 23 and 24: opportunitiesgrowing, suggesting co
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Page 27 and 28: opportunitiesPractices that sequest
Page 31: Chapter 4ChallengesDeveloping worka
Page 39 and 40: challengesinnovation by agricultura
Page 41 and 42: Chapter 5The way forwardFoundations
Page 43 and 44: the way forwardthe strategic object
Page 45 and 46: the way forwardassess carbon seques
Page 47 and 48: eferencesBoyd, E., Corbera, E. & Es
Page 49 and 50: eferencesGifford, R.M., Cheney, N.P
Page 51 and 52: eferencesLal, R., Kimble, J.M. & St
Page 53 and 54: eferencesPaustian, K., Collins, H.P
Page 55 and 56: eferencesSoussana, J.F., Allard, V.
Page 57 and 58: AcknowledgementsIn April 2009, 20 i
Page 59 and 60: Policy briefPastoralistsPlaying a c
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policy briefpost copenhagen agricul
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policy brief>N0 2 000 4 000kilomete
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Challenges and opportunities for ca
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