Challenges and opportunities for carbon sequestration in ... - FAO

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Challenges and opportunities for carbon sequestration in grassland systemsA Technical Report on Grassland Management and Climate Change MitigationIn addition to enhancing forage production and food security,many land management practices that sequester carbon prompt otherchanges in environmental processes that are beneficial for other reasons.Practices that sequester carbon in grassland soils tend to maximizevegetative cover, reducing wind and water-induced erosion (Follett,Kimble and Lal, 2001). Reducing sediment load increases water qualitywhile reducing airborne particulate matter improves air quality. Carbonsequestering practices can also enhance ecosystem water balance;building soil organic matter stocks tends to enhance water infiltrationand soil moisture status in arid-semi-arid environments (Unger et al.,1991). In many cases practices that sequester carbon can lead to greaterbiodiversity (Bekessy and Wintle, 2008).CO 2CH 4N 2O Agreement EvidenceGrazing intensity +/- +/- +/- * *Increased productivity(e.g. through fertilization)+ +/- ** *Nutrient management + +/- ** **Fire management + + +/- ** *Species introductions(incl. legumes)+ +/- * **Table 1: Mitigative effects of various aspects of grazing land improvementSource: Reproduced from IPCC, 2007aMost grassland management practices with the potential to sequestercarbon were developed to address issues other than carbon sequestration.For example, expanding grasslands through agricultural set-asides andrehabilitating degraded rangelands are often intended to arrest windand water erosion (Lal, 2009a). Practices that preserve the habitat, likegrassland preservation, rehabilitation, etc., can preserve species andbiodiversity. A variety of practices that integrate grass species into arablecrop rotation (for example, catch crops used to retain nutrients, covercrops to reduce erosion, grass crops in rotation) sequester carbon and alsoretain nutrients in agricultural systems, reducing downstream pollution(Stevens and Quinton, 2009).18Integrated Crop Management
opportunitiesPractices that sequester carbon in grasslandscan enhance adaptation to climate changeMitigation investments are crucially important for reducing the impactsof climate change, but GHG concentrations will continue to increasefor decades despite implementation of even the most aggressive climatepolicies (IPCC, 2007a). Therefore, adaptation is an important responseto climate change that should begin now (IPCC, 2007b). Because yieldreductions under drought, heat stress, floods and other extreme eventswill be the most consequential, negative impacts of climate change, effortsto adapt to a changing climate should focus on increasing the resilienceof management systems (FAO, 2008a; WMO, 2007). The increasingfrequency of droughts in the drylands (Thornton et al., 2008) and droughtsof longer duration are expected to have a substantial negative effect onthe sustainability and viability of livestock production systems in semiaridregions. Grassland management practices maximize the infiltration,capture and utilization of precipitation for production (Woodfine, 2009).In cases where sustainable grazing management increases soil carbonstocks, soil water holding capacity increases. Both facets of enhancingwater balance will increase drought resilience.Grassland management practices that sequester carbon tend to makesystems more resilient to climate variation and climate change: increasedsoil organic matter (and carbon stocks) increases yields (Vallis et al., 1996;Pan et al., 2006); soil organic matter also enhances soil fertility, reducingreliance on external N inputs (Lal, 2009b). Surface cover, mulch and soilorganic matter all contribute to a decrease in interannual variation inyields (Lal et al., 2007); and practices that diversify cropping systems,such as grass and forage crops in rotation, sequester carbon and enhanceyield consistency.Agricultural practices intended to mitigate GHG emissions couldincrease vulnerability to climate variation and climate change, if theyincrease the energy supply from food production systems (e.g. to supplybiomass energy), or prevent arable land from being cultivated (e.g.afforestation). Similarly, actions intended to foster adaptation could leadto increased emissions: e.g. increased N fertilization (and N 2O release)to enhance yields or harvest of stover for conversion to biofuels (IPCC,Vol. 9–201019
Page 1: Integrated Crop Management Vol. 9 -
Page 4 and 5: The designations employed and the p
Page 7: Executive SummaryImplementing grass
Page 11 and 12: Chapter 2BackgroundGrasslands cover
Page 13 and 14: ackgroundGrasslands are intensively
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
Page 25: opportunities©FAO/m. marzotnationa
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
Page 61 and 62: policy briefMuch of the world’s g
Page 63 and 64: policy briefpost copenhagen agricul
Page 65 and 66: policy brief>N0 2 000 4 000kilomete
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