Why trees mean development

Transcription

1 Why trees mean development

2 Global forest cover

3 Prevalence of trees on farms

4 The full view shows that trees

5 and people cohabit everywhere. Global population density

6 Who are we? One of the 15 CGIAR research centres employing about 500 scientists and other staff. We generate knowledge about the diverse roles that trees play in agricultural landscapes We use this research to advance policies and practices that benefit the poor and the environment. 2

7 Our HQ & regional research nodes

8 We seek answers to this challenge: by 2050, we need to Double world food production on ~ the same amount of land Make farms, fields and landscapes more resistant to extreme weather, while massively reducing GHG emissions. 3

9 Land use emissions 30.9% 5) Including agricultural waste burning and savannah burning (non-co2). CO2 emissions and/or removals from agricultural soils are not estimated in this database. 6) Data include CO2 emissions from deforestation, CO2 emissions from decay (decomposition) of above-ground biomass that remains after logging and deforestation, and CO2 from peat fires and decay of drained peat soils. Chapter 9 reports emissions from deforestation only. IPCC AR4 GHG emissions by sector in 2004 [Figure 1.3b].

10 Galma, Niger, 1975 & 2003

11 Kg per Hectare Top issue: yields Cereal yields by region, East Asia Latin America South Asia Sub-Saharan Africa 0 World Bank World Development Indicators

12 African farm facts Population growth has rendered fallowing impossible in many communities Land overuse is depleting soil organic matter, soil carbon and soil microbiology Consequently, across drylands Africa, soil fertility is dropping Deep poverty and logistical bottlenecks makes fertiliser unaffordable for most Funding for fertiliser subsidies is scarce and fickle Where will soil fertility, soil organic matter and extreme weather resilience come from? 11

13 From trees. Faidherbia Albida in teff crop system in Ethiopia

14 Malawi (Maize & Gliricidia)

15 Fertilizer trees outperform NPK. 2009/2010 season; data from 6 Malawi districts Plot management Sampling Frequency Mean (Kg/Ha) Standard error Maize without fertiliser Maize with fertiliser Maize with fertiliser trees Maize with fertiliser trees & fertiliser Mwalwanda, A.B., O. Ajayi, F.K. Akinnifesi, T. Beedy, Sileshi G, and G. Chiundu

16 Oil palm, Brazil Oil palms intercropped with annuals for first 3-4 years (cassava, maize, short-cycle legumes) Mixed with other trees : Fruit: cacao, açaí (euterpe oleracea), banana Timber, N-fixing trees Intense management, slash-andmulch Planted in early 2008 Oil yields: Plot 1 (81 plants/ha) Plot 2 (99 pl/ha) Plot 3 (99 pl/ha) Monocrop (143 pl/ha) 8 tons ha -1 yr tons ha -1 yr tons ha -1 yr -1 5 tons ha -1 yr -1

17 Why?

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20 Drought protection of trees Forestry: most roots close to surface Agroforestry: most roots at depth Root density: meters of rootlets /m 3 of soil Root density: meters of rootlets /m 3 of soil Depth (cm) Depth (cm)

21 C3/C4 plant productivity versus T Biomass yield Wheat Maize T (C)

22 % of sunlight used by photosynthesis Agriculture Forestry Agroforestry Light intercepted : Walnut Walnut : Wheat 0.73 Wheat : Not used Year

23 Key concept: the Land Equivalency Ratio

24 France (cereals & fruit tree bocage)

25 Niger (Millet & Faidherbia albida)

26 France (Wheat & juglans nigra) agroof Liagre F., personal communication

27 Brazil (oil palm, annuals, cocoa, açai, banana)

28 England (willow & annuals)

29 Sumatra (rubber +++)

30 Sweden (reindeer sylvopastoral)

31 Galma, Niger, 1975 &

32 Then... Zinder, Niger, 1980s

33 ... and now. Zinder, Niger, today. These 5 million hectares of new agroforest parklands are yielding 500,000 tonnes more than before. (Reij, 2012)

34 Kantché district, Zinder, Niger 350,000 people, rainfall ca. 350 mm / year, typical of Sahel drylands. Annual district-wide grain surplus: ,230 tons drought ,838 tons ,122 tons ,208 tons ,818 tons drought. Yamba & Sambo,

35 Agroforests in the Sahel

36 Sumatra (Indonesia) Rubber plantation Farm/plantation size 1,000 15,000 Ha 3 5 Ha Income after costs Ha -1 Yr -1 (USD) Improved germplasm jungle rubber garden ~ 800 ~ 3,000-3,000 N of value chains 1 > 10 Biodiversity ratio (compared to biodiversity of undisturbed local land) ~ 2% ~ 60% Phytosanitation use High Low to nil Social costs Medium to high Low to nil Environmental costs Very high Low Leakey, 2012

37 Pest control

38 Huge mitigation potential Humid Dry Mbow (2012)

39 Trees and rain

40 Rain: whence and where to? Much of the rain that falls on land evaporated from plants, not from the seas. Example: in the western Sahel, over 60% of rain originally evaporated from east African plants. P from Et /P In much of the world, most of the water that falls as rain evaporates again through the transpiration of plants, rather than flowing to the sea. That water falls on other lands. P: precipitation Et: evapotranspiration E: evaporation E/P van der Ent RJ, Savenije HHG, Schaefli B, Steele Dunne SC, Origin and fate of atmospheric moisture over continents. Water Resources Research 46, W09525,

41 Deforesting indochina will reduce rainfall in China

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47 Soil degradation worldwide

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49 Selected yields by farm size Smallest ¼ of all farms Largest ¼ of all farms FAO, State of Food and Agriculture 2014

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52 Investment in normal agriculture Investment in agroforestry

53 The agroecological Babel Agroecological approaches Ecological Farming Forest Landscape Restoration Sustainable intensification Sylvopastoral systems Diversification Perenialisation Biodynamic agriculture Intercropping Climate Smart Agriculture Organic Farming Permaculture Restorative Agriculture Ecological agriculture Restoration Agriculture Agroforestry Conservation Agriculture Farming Gods Way Holistic Grazing Management Syntropic agriculture CAWT EverGreen Agriculture FMNR IPM Push-Pull Fertiliser Tree Technology Intercropping

54 Thank you

55 Crop yield (tonnes per hectare) The yield gap lesson Typical African yield Simple AF yield Typical EU yield Advanced variety yield GMOs Advanced Agroecology & intrants Simple agroecology

56 Soil moisture in a warming world Percentage changes from to in the multimodel ensemble mean soil-moisture content in the top 10 cm layer (broadly similar for the whole soil layer) simulated by 11 CMIP5 models under the RCP4.5 emissions scenario. Stippling indicates at least 82% (9 out of 11) of the models agree on the sign of change. Dai, A., Increasing drought under global warming in observations and models, Nature Climate Change 3, (2013)