which ways forward for sustainable cotton production in ...€¦ · •increase organic matter and...

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Which ways forward for sustainable cotton production in Africa in the context of climate change?

Bruno BACHELIER, Oumarou BALARABÉ, Stéphane BOULAKIA, Julien DEMENOIS,

Edward GERARDEAUX, François-Régis GOEBEL & Romain LOISON

CIRAD (Centre for International Cooperation in Agronomic Research for Development, France)

ICAC 77th Plenary Meeting, Abidjan, Côte d’Ivoire, 2-6 December 2018

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• Climate change in Africa and expected impacts in cotton cultivation


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IPCC climate predictions for Africa (Fifth assessment report, 2014)

Temperature: +1 to +4°C by 2100

Rainfall:• Scenario RCP 2.6: few changes (hatched)• Scenario RCP 8.5: a rainfall diminution in

West Africa (-5 to 10 %), a rainfallaugmentation in Central and East Africa (+5 to 10 %), and many uncertainties for coastal zones: Ghana, Togo, Bénin, Nigéria.

CO2 concentration: 410 (June 2018) to 475-800 ppm according to scenarii

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Expected impacts in cotton cultivation

On cotton physiology and yields:

• ITC 2011▪ China: shorter cycle, more rain positive effect

▪ India: extreme temperatures & higher rain intensity negative effect

▪ USA: carbon enrichment, more hot days variable effects

▪ Pakistan: less water available for irrigation negative effect

▪ Brasil variable effects

▪ West and Central Africa unclear effects

• Positive effect on yield and precocity in Cameroun (Tingem 2011; Gérardeaux et al 2013 and 2017)

• Negative effect on yields in Ghana, Burkina Faso et Côte d’Ivoire (Läderach et al 2011; Diarra et al. 2017)

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On insect pests of cotton cropping systems:

• Insects are sensitive to temperature variations, are able to adapt rapidly to environmental changes, and can extend their distribution

• In some cases natural ennemies of cotton pests do not follow the change of pest status and pest population can spread out without biocontrol

• CC and particularly global warming may disturb the biodiversity equilibriumin the ecosystem and the pressure and role of natural ennemies candecrease or be severely affected.

• It is important to conceive and implement innovative cropping systems and promote conservation agriculture and all agroecology methods that are able to reduce pest infestation.


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How does climate change affect all this?

• Disruption of the ecosystem at all trophic levels and in the interactions between these different levels: cultivated plants, natural habitats, pests and diseases, natural enemies.

• Potentially negative effects of temperature rise on host plant resistance expression. It has also been hypothesized that CC could influence an already established biological control by deregulating the interactions of natural enemies with pests, due to a greater sensitivity of higher trophic levels to these changes.

➢Hence the need to adapt cropping systems to these disturbances by changing practices.

➢With regard to mitigating the global impact of certain practices, in terms of aggravating CC, there may be incentives to change practices at the local level.

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Need for cotton innovative systems to preserve resources and biodiversity

• Preserve water

• Increase organic matter and carbone storage

• Control of pests and weeds (attract and kill pests, attract predators, push-pull systems)

Possible solutions:

• Mulch / trash in the soil to preserve biodiversity and humidity

• Introduction of companion plants

• Adapted cotton varieties


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• Sustainable land management


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Selection of Sustainable Land Management

techniques mobilizing processes of Ecological Intensification of

cropping and production systems

WOCAT classification (World Overview of Conservation Approaches and Technologies)

Sustainable land management

Herbaceous and shrub forage productionRotary parkingManure stableLive hedge, embocking and diversification

Rotation and rotationIntegration of grain legumesIntegration of improving legumesImproved short cycle fallowCompostingShredding of residues (cotton and others)

Minimum and localized work ("strip tillage")Mechanized "zaï in line"

Evolution from resumption of fallows / improved inter-croppingEvolution from "strip-tillage" and recovery of grazing areaSowing on crop residues

Yam under woody cover of GliricidiaAnnual intercropping of cashew treesPark with trees (Acacia albida or other)

Integrated Soil Fertility Management

Water and soil conservation

Conservation Agriculture (CA)

Agroforesterie (AF)

Integrated Agriculture and Livestock Management

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Crotalaria juncea, Vertisol, Cameroon Crotalaria spectabilis Crotalaria ochroleuca

Crotalaria juncea, CambodiaPigeon pea, dry season, Cerrado, Brasil

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The “field” and “farm” scale levels are insufficient when “higher” constraints regulate crop and production systems, such as:

• grazing pasture

• fire

• access to land

Innovation must at the same time address these higher scale levels of constraint:

• plot terroir / territory

• farm village community

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In rainfed systems: agro-ecological transition in the absence of control of “animalwandering”, association with crops that are not / not very palatable to livestock

Cassia obtusifolia Crotalaria retusa


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Development of village terroirs

Corridor, fencing and vegetation cover(Alysicarpus sp.)

Cameroon


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Development of terroirs and restorative fallow

land

Recovery of degraded soil and forage

production

(Stylosanthesguianensis)

Cameroon

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Development of village terroirs

Recovery of degraded soils (Crotalaria juncea)

Cameroon


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Support for sustainable mechanization with a twofold dimension

• How to mechanize sustainable systems?technical: performance, resilience...what mechanization for agro-ecological standards

• How to make mechanized systems sustainable?socio-economics: access, cost, maintenance...

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• Soil organic matter management


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Soil organic matter management

• Increase of water capacity retention in sandy soils (Minasny et al. 2017)

• Decrease sensitivity to soil erosion (Blanco-Canqui et Lal 2007)

• Higher availability of nutrients (Vanlauwe et al. 2005)

• Better efficiency of inputs use (Tittonnel et al. 2008)

• Higher diversity of soil micro-organisms (Briat el al. 2017)

Increase organic matter inputs in soil and reduce losses (Fujisaki et al. 2018)

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No tillage

AgroforestryWater management

Integrated management of soil fertility

Organic inputs

Agroecology


A set of practices

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Increase soil carbon stocks to:

Improve food security

Adapt to climate change

Mitigate climate change

and contribute to Sustainable Development Goals:

www.4p1000.org

40 countries / 280+ organizations


States, companies, farmers, NGOs, research institutes… can join the 4 per 1000 Initiative

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Atmosphere830 GtC

Vegetation450-650 GtC

Minasny et al. (2017)

Soil 0 - 2 m2,400 ± 230 GtC


Why 4 per 1000?

www.4p1000.org

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• Pest management


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• Objectives:

1. Manage locally phytosanitary risks exacerbated by CC (in order to adapt cropping systems to its effects)

2. Adapt phytosanitary practices to mitigate/not increase the risks of CC on a global scale

3. Prevent/anticipate the introduction/establishment of pest that have become potentially invasive/emerging due to CC.

• The reduction of losses due to pest also reduces unnecessary investments in inputs (fertilizers, synthetic pesticides) with a high carbon footprint, for the part of production "lost" because of these losses (Carlton et al. 2012).

Pest management

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Pest management

Agro-ecological farming practices can mitigate the effects of CC while reducing pest pressure

• In North Cameroon:

➢ Positive effect of mulch (particularly Brachiaria ruziziensis) demonstrated on a disease, cotton blight, probably via microclimate (by reducing high temperatures and water stress that favour fusariose)

➢ Positive effect on Striga/cereals via other pathways, but negative on diplopods causing damage to seedlings, even following the example of Madagascar, the greater abundance and diversity of arthropods in conservation farming systems compared to the ploughed control was more likely to be predators than phytophages.

• Work done by CIRAD (Thierry Brévault and Krishna Naudin)

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Egg parasitoid Trichograms, CC sensitive

Predatory ants, very present in the fields

Boll pest Lepidoptera

Solu

tio

ns

Preservingfunctionalbiodiversity

Pest management

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• Pest management

• Cultivar adjustment


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• Meta-analysis on maize, wheat and rice (n = 1700):

Cultivar adjustment = most effective adaptation strategy (Challinor et al, NCC 2014)

Cultivar adjustment

28(adapted from Challinor et al, Nature Climate Change, 2014 supplementary material)

Cultivar adjustment

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• Meta-analysis on maize, wheat and rice (n = 1700):

Cultivar adjustment = most effective adaptation strategy (Challinor et al, NCC 2014)

• Earliness

• Better adaptatibilty

• Drought resistant / water efficient (Water Use Efficiency)

• Leaf thickness, hairiness

• More compact (less vegetative branches, shorter fruiting branches)

• High density adapted cultivars

Cultivar adjustment

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• Pest management

• Cultivar adjustment

• Conclusion


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Constraints specific to Africa....

• Lack of collected climate data, making predictions uncertain

• Variable effects by subregion

• Vulnerability of agricultural holdings due to low adaptability

Conclusion

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...but there are possibilities of adaptation…

• Changes in sowing dates,

• Several crop cycles in areas with long wet seasons,

• Permanent soil cover to reduce erosion,

• Minimum tillage

• Integrated pest and disease management

• Varietal adaptation to counter increased precocity, drought-tolerant varieties

…and Governments can also get involved

• By joining the 4 per 1000 Initiative

• By promoting the use of sustainability indicators (SEEP/ICAC…)

Conclusion

which ways forward for sustainable cotton production in ...€¦ · •increase organic matter and...

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