Agroforestry systems for mitigating climate change and reducing Carbon Footprints of land-use systems in Southern Africa

Abstract

Farming systems in Southern Africa are mostly maize mixed cropping, with some tree and/or root crop-based systems. Agroforestry systems (AFS), in particular, represent a model for ecological sustainability, with the potential of sequestering carbon (C) within soils and biomass. This review reveals that rotational woodlots sequester more C than other AFS types in the region. Additionally, C levels above and below ground range from 0.29 to 15.21 Mg ha^-1 yr^-1 and 30 to 300 Mg C ha^-1 in the first 100 cm soil depth, respectively. To measure C below- and aboveground biomass in different AFS, variable - and not easily adoptable - methodologies are being used in Southern Africa, which limits the standardization of C stock accounting. Since the magnitude of C sequestered in AFS is dependent on the species used, AF and farm management, and environmental conditions, we recommend the adoption of rigorous and replicable methodologies to account for C stocks in different AFS over time in Southern Africa.

Keywords

Aboveground carbon / agroforestry systems / sequestration / soil organic carbon

References

[1] IPCC. Climate change 2014: mitigation of climate change. Contribution of working group III to the fifth assessment report of the intergovernmental panel on climate. Cambridge: Cambridge University Press; 2014.

[2] Montagnini F.Carbon sequestration: an underexploited environmental benefit of agroforestry systems.Agrofor Syst2004;61-62:281-95

[3] IPCC. Climate change 2007: mitigation. contribution of working group III to the fourth assessment report of the intergovernmental panel on climate change. In Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA editors. Cambridge; New York, NY: Cambridge University Press. https://www.ipcc.ch/site/assets/uploads/2018/03/ar4_wg3_full_report-1.pdf [Last accessed on 6 Dec 2022].

[4] IPCC. Use of models and facility-level data in greenhouse gas inventories. In Proceedings of the IPCC expert meeting on use of models and measurements in greenhouse gas inventories. Sydney, Australia; 2010.

[5] Zomer RJ,Coe R. Trees on farm: an analysis of global extent and geographical patterns of agroforestry, ICRAF working paper no. 89. Nairobi, Kenya: World Agroforestry Centre; 2009.

[6] Nair PKR.Carbon sequestration studies in agroforestry systems: a reality-check.Agroforest Syst2012;86:243-53

[7] Nair PR.“Solid-fluid-gas”: the state of knowledge on carbon-sequestration potential of agroforestry systems in Africa.Curr Opin Environ Sustain2014;6:22-7

[8] De Foresta HE, Somarriba A, Temu D, Boulanger H, Feuilly M, Toward the assessment of trees outside forests. Resources assessment working paper. Rome: FAO; 2013.

[9] Albrecht A,Blanchart E,Vanlauwe B.Below-ground inputs: relationships with soil quality, soil C storage. In: Noordwijk MV, Cadisch G, Ong CK, editors. Below-ground interactions in tropical agroecosystems: concepts and models with multiple plant components. Wallingford: CABI Publishing; 2004. pp. 193-207.

[10] Ramachandran Nair P, Nair V. Carbon storage in North American agroforestry systems. In: Kimble J, Lal R, Birdsey R, Heath L, editors. The potential of U.S. forest soils to sequester carbon and mitigate the greenhouse effect. Boca Raton: CRC Press; 2003.

[11] Makundi WR.Mitigation potential and cost in tropical forestry - relative role for agroforestry.Environ Dev Sustain2004;6:235-60.

[12] Haile SG,Nair VD.Carbon storage of different soil-size fractions in Florida silvopastoral systems.J Environ Qual2008;37:1789-97

[13] Nair PK, Mohan Kumar B, Nair VD. Agroforestry as a strategy for carbon sequestration.J Plant Nutri Soil Sci2009;172:10-23

[14] IPCC. Land use, land-use change, and forestry. a special report of the IPCC. Cambridge: Cambridge University Press; 2000.

[15] Sanchez PA.Linking climate change research with food security and poverty reduction in the tropics.Agric Ecosyst Environ2000;82:371-83

[16] Roshetko JM,Hairiah K.Carbon stocks in Indonesian homegarden systems: Can smallholder systems be targeted for increased carbon storage?.Am J Altern Agric2002;17:138-48Available from: https://www.jstor.org/stable/44503228 [Last accessed on 7 Dec 2022].

[17] Sharrow S.Carbon and nitrogen storage in agroforests, tree plantations, and pastures in western Oregon, USA.Agrofor Syst2004;60:123-30

[18] Kirby KR.Variation in carbon storage among tree species: implications for the management of a small-scale carbon sink project.For Ecol Manag2007;246:208-21

[19] Palm C,Van Noordwijk M.Mitigating GHG emissions in the humid tropics: case studies from the alternatives to slash-and-burn program (ASB).Environ Dev Sustain2004;6:145-62

[20] Nair PKR,Mosquera-Losada MR. Agroforestry. In Jorgensen SE, Faith BD, editors, Encyclopedia of ecology, Oxford: Elsevier; 2008, pp. 101-10.

[21] Akinnifesi FK,Ajayi OC.Contributions of agroforestry research to livelihood of smallholder farmers in Southern Africa: 1. Taking stock of the adaptation, adoption and impact of fertilizer tree options.Agric J2008;3:58-75

[22] Khumalo S,Moyo B.The status of agrobiodiversity management and conservation in major agroecosystems of Southern Africa.Agric Ecosyst Environ2012;157:17-23

[23] Garrity DP,Ajayi OC.Evergreen agriculture: a robust approach to sustainable food security in Africa.Food Sec2010;2:197-214

[24] Moyo BHZ. The role and use of indigenous knowledge in small-scale agricultural systems in Africa: the case of farmers in northern Malawi. Ph.D thesis. Glasgow: University of Glasgow; 2008.

[25] Sørensen C. Control and sanctions over the use of forest products in the Kafue river Basin of Zambia. Rural Development forestry network paper 15a. London: Overseas Development Institute; 1993.

[26] Soones I. Livestock populations and the household economy: a case study from southern Zimbabwe. Ph.D thesis, London: Imperial College; 1990.

[27] Musinguzi E. An analysis of the agro-ecological systems, biodiversity use, nutrition and health in selected east and Southern Africa countries. Rome: Biodiversity International; 2011. 38p.

[28] Chidumayo EN.A shifting cultivation land use system under population pressure in Zambia.Agrofor Syst1987;5:15-25

[29] Landry J.Analysis of the potential socio-economic impact of establishing plantation forestry on rural communities in Sanga district, Niassa province, Mozambique.Land Use Policy2011;28:542-51

[30] Sileshi GW,Akinnifesi FK.Agroforestry: fertilizer trees.Encycl Agric Food Syst2014;1:222-234

[31] Sollins P,Kramer M.Stabilization and destabilization of soil organic matter - a new focus.Biogeochemistry2007;85:1-7

[32] Nyamadzawo G,Wuta M.Maize yields under coppicing and non coppicing fallows in a fallow-maize rotation system in central Zimbabwe.Agroforest Syst2012;84:273-86

[33] Mafongoya PL.Biomass production of tree fallows and their residual effect on maize in Zimbabwe.Agrofor Syst1999;47:139-51

[34] Prescott C,Weetman G.Long-term effects of repeated N fertilization and straw application in a jack pine forest: 3. Nitrogen availability in the forest floor.Can J For Res1995;25:1991-6

[35] Prescott C,Weetman G.Long-term effects of repeated N fertilization and straw application in a jack pine forest: 2. Changes in the ericaceous ground vegetation.Can J For Res1995;25:1984-90

[36] Horwath W.Carbon cycling and formation of soil organic matter. In: Paul EA, editor. Soil microbiology, ecology, and biochemistry. Burlington: Academic; 2007. pp. 303-39.

[37] Soto-Pinto L,Mendoza J,de Jong B.Carbon sequestration through agroforestry in indigenous communities of Chiapas, Mexico.Agrofor Syst2010;78:39-51

[38] Nyamadzawo G,Chikowo R,Mafongoya PL.Soil and carbon losses under rainfall simulation from two contrasting soils under maize-improved fallows rotation in Eastern Zambia. In Roose EJ, Lal R, Feller C, Barthes B, Stewarts BA, editors. Soil Erosion and Carbon Dynamics. Boca Raton: CRC Publishers, Taylor and Francis Group; 2006. pp. 197-206.

[39] Lal R.Agroforestry systems and soil surface management of a tropical alfisol. Parts I-VI.Agrofort Syst1989;8:97-111

[40] Nyamadzawo G,Nyamugafata P.Improved legume tree fallows and tillage effects on structural stability and infiltration rates of a kaolinitic sandy soil from central Zimbabwe.Soil Tillage Res2007;96:182-94

[41] Nyamadzawo G,Chikowo R.Partitioning of simulated rainfall in a kaolinitic soil under improved fallow-maize rotation in Zimbabwe.Agrofor Syst2003;59:207-14

[42] Gama-Rodrigues EF,Nair VD,Baligar VC.Carbon storage in soil size fractions under two cacao agroforestry systems in Bahia, Brazil.Environ Manag2010;45:274-83

[43] Kaonga M.Modelling soil organic carbon turnover in improved fallows in eastern Zambia using the RothC-26.3 model.Model For Ecol Manag2008;256:1160-6

[44] Nyamadzawo G,Nyamugafata P,Giller KE.Soil organic carbon dynamics of improved fallow-maize rotation systems under conventional and no-tillage in Central Zimbabwe.Nutr Cycl Agroecosyst2008;81:85-93

[45] Kimaro AA. Sequential agroforestry systems for improving fuelwood supply and crop yield in semi-arid Tanzania. Ph.D thesis, Toronto: University of Toronto; 2009. 123p.

[46] Makumba W,Oenema O.Influence of time of application on the performance of Gliricidia prunings as a source of N for maize.Exp Agr2006;42:51-63

[47] Okorio J.The growth and yield of Acacia albida intercropped with maize (Zea mays) and beans (Phaseolus vulgaris) at Morogoro, Tanzania.For Ecol Manag1994;64:183-90

[48] Stromgaard P.Biomass, growth, and burning of woodland in a shifting cultivation area of South Central Africa.For Ecol Manag1985;12:163-78

[49] Chidumayo EN.Effects of accidental and prescribed fires on miombo woodland, Zambia.Commonw For Rev1997;6:268-72Available from: https://www.jstor.org/stable/42610031 [Last accessed on 7 Dec 2022].

[50] Nyadzi GI,Banzi FM.Rotational woodlot technology in northwestern Tanzania: tree species and crop performance.Agrofor Syst2003;59:253-63

[51] Kaonga ML.Carbon pools in tree biomass and the soil in improved fallows in eastern Zambia.Agrofor Syst2009;76:37-51

[52] Malunguja GK,Kilonzo M.Climate change mitigation through carbon dioxide (CO2) sequestration in community reserved forests of northwest Tanzania.Arch Agric Environ Sci2020;5:231-40

[53] Handavu F,Sileshi GW.Aboveground and belowground tree biomass and carbon stocks in the miombo woodlands of the Copperbelt in Zambia.Carbon Manag2021;12:307-21

[54] Chirwa PWC,Geldenhuys CJ.Managing Southern African woodlands for biomass production: the potential challenges and opportunities. In: Seifert, T, editor. Bioenergy from wood: sustainable production in the tropics, managing forest ecosystems. Cham: Springer; 2014. pp. 67-87.

[55] Musokwa M,Zungu M.Soil macro fauna indices and their association with physical soil properties under agroforestry systems.Int J Agrofor Silvic2020;8:001-9

[56] Sileshi G,Ajayi OC.Contributions of agroforestry to ecosystems services in the miombo eco-region of eastern and southern Africa.Afr J Environ Sci Technol2007;1:68-80

[57] Dinesh D,Bonilla-findji O. 10 Best bet innovations for adaptation in agriculture: a supplement to the UNFCCC NAP technical guidelines. Wageningen: The Netherlands; 2017.

[58] Sheppard JP,Borrass L.Agroforestry: an appropriate and sustainable response to a changing climate in Southern Africa?.Sustainability2020;12:6796

[59] Rhoades C.Seasonal pattern of nitrogen mineralization and soil moisture beneath Faidherbia albida (syn Acacia albida) in central malawi.Agrofor Syst1995;29:133-45

[60] Henry M,Trotta C.Estimating tree biomass of sub-Saharan African forests: a review of available allometric equations.Silva Fenn2011;45:477-569

[61] Vieilledent G,Andriamanohisoa SFD.A universal approach to estimate biomass and carbon stock in tropical forests using generic allometric models.Ecol Appl2012;22:572-83

[62] IPCC. Good practice guidance for land use, land-use change and forestry. In Penman J, Gytarsky M, Hiraishi T, editors. IPCC national greenhouse gas inventories programme. Kanagawa: Institute for Global Environmental Strategies (IGES); 2003.

[63] Wadham-Gagnon B. Estimating carbon stocks in tropical hardwood plantations: using species-specific and non-destructive parameters to estimate aboveground biomass for six native species in Panama. Internship Report. 2006. Available from: https://docplayer.net/101099556-Benjamin-wadham-gagnon-diana-sharpe.html [Last accessed 8 Dec 2022]

[64] Saglan B,Bilgili E,Basal I.Estimating fuel biomass of some shrub species (Maquis) in Turkey.Turk J Agric2008;32:349-56Available from: https://journals.tubitak.gov.tr/agriculture/vol32/iss4/13 [Last accessed on 7 Dec 2022].

[65] Dong L,Li F.Additive biomass equations based on different dendrometric variables for two dominant species (larix gmelini rupr. and betula platyphyllasuk.) in natural forests in the eastern daxing’an mountains, Northeast China.Forests2018;9:261

[66] Picard N,Henry M. Manual for building tree volume and biomass allometric equations: from field measurement to prediction. Montpellier: Food and Agricultural Organisation of the United Nations, Rome and Centre de Coorperation Internationale en Recherche Agronomique pour le Development; 2012; 215p.

[67] Robinson D.Implications of a large global root biomass for carbon sink estimates and for soil carbon dynamics.Proc Biol Sci2007;274:2753-9 PMCID:PMC2279225

[68] Koala J,Savadogo P,Helskanen J.Allometric equations for below-ground biomass of four key woody species in West African savanna-woodlands.Silva Fenn2017;51

[69] Scharlemann JPW.Hiederer R, Kapos V. Global soil carbon: understanding and managing the largest terrestrial carbon pool.Carbon Manag2014;5:1, 81-91

[70] Ciais P,Williams M.The carbon balance of Africa: synthesis of recent research studies.Philos Trans A Math Phys Eng Sci2011;369:2038-57

[71] Handavu F,Syampungani S.A review of carbon dynamics and assessment methods in the miombo woodlands.South For A J For Sci2017;79:95-102

[72] Donovan P. Measuring soil carbon change: a flexible, practical, local method. 2013. Available from: https://soilcarboncoalition.org/files/MeasuringSoilCarbonChange.pdf [Last accessed on 7 Dec 2022].

[73] Ryan CM,Grace J.Above- and Belowground Carbon Stocks in a Miombo Woodland Landscape of Mozambique.Biotropica2011;43:423-32

[74] Vågen T,Singh BR.Soil carbon sequestration in sub-Saharan Africa: a review.Land Degrad Dev2005;16:53-71

[75] Makipaa R,Guendehou S,Kaaya A. Soil carbon monitoring using surveys and modelling: general description and application in the United Republic of Tanzania. FAO Forestry Paper 168. Rome: FAO; 2012.

[76] Walsh MG. The land degradation surveillance framework: guide to field sampling and measurement procedures. Nairobi: World Agroforestry Centre; 2006.

[77] Vagen TG,Tondoh JE. The land degradation surveillance framework: field guide; 2013. Available from: https://www1.cifor.org/fileadmin/subsites/sentinel-landscapes/document/LDSF_Field_Guide.pdf [Last accessed on 8 Dec 2022].

[78] Ellert BH,Entz T.Assessment of a method to measure temporal change in soil carbon storage.Soil Sci Soc Am J2002;66:1687-95

[79] Walker SM.The impact of land use on soil carbon in Miombo Woodlands of Malawi.For Ecol Manag2004;203:345-60

[80] Makumba W,Janssen B.Long-term impact of a gliricidia-maize intercropping system on carbon sequestration in southern Malawi.Agric Ecosyst Environ2007;118:237-43