Triple Green–Finding ways to meet the dual challenge of enhancing
food production and meeting new sustainability criteria
...
Human growth
20/80 dilemma
Ecosystems
60 % loss dilemma
Climate
550/450/350
dilemma
Surprise
99/1 dilemma
TThe
Quadruple
S...
Dual challenge – environment
and development
• Meeting food requirements – MDG’s
• Reducing atmospheric CO2 levels to 350 ...
Climate
Change
Ocean
acidification
Ozone
depletion
Global
Freshwater
Use
Rate of
Biodiversity
Loss
Biogeochemical
loading:...
Climate Change
< 350 ppm CO2 < 1W m2
(350 – 500 ppm CO2 ;
1-1.5 W m2)
Ocean acidification
Aragonite saturation
ratio > 80 ...
Example - carbon sequestration in
terrestrial ecosystems
• Carbon sequestration by
reforrestation
• Carbon sequestration i...
Reforrestation
An annual C seq rate of 1.6 GtC/yr by 2050 (Hansen
et al) results in:
• 1300 km3/yr increased consumptive w...
C seq on agricultural lands –
Preliminary estimates
An annual C seq rate of 0.4-1.2 GtC/yr by 2050 (Lal
et al) results in:...
Key question:
Are the current agricultural
techniques sufficient to meet this
dual challenge?
The Triple Green project - Niger
Agricultural management interventions for a new
green revolution, in a green (sustainable...
Triple Green - Rationale
Small scale agriculture in SSA
• Low yields
• Erratic rainfall
• Nutrient deficiency
Possible to ...
Triple Green - Methods
Two important ways to improve yields are:
A)Bridging dry-spells by implementing water harvesting
fo...
Triple Green – nutrients + water
0
50
100
150
200
250
Cropyieldimprovements(%)
Non fertilised
Fertilised
CA WH WSD
Triple Green – climate change
Mitigation: Productive sanitation + water harvesting
systems can contribute to increasing th...
Randomised block-trial on supplementary
irrigated, urine fertilised millet
Expected results
Field data will be combined with a physically based
ecosystems model to study:
• Carbon sequestration, wa...
Scaling out
To answer this questions, we need:
• Assessments across scales
• Integrated assesments focussing on several su...
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Triple Green-Agricultural Management Interventions for a New Green Revolution

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This study was presented during the conference “Production and Carbon Dynamics in Sustainable Agricultural and Forest Systems in Africa” held in September, 2010.

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Triple Green-Agricultural Management Interventions for a New Green Revolution

  1. 1. Triple Green–Finding ways to meet the dual challenge of enhancing food production and meeting new sustainability criteria Louise Karlberg, SEI ABSTRACT: Sub-Saharan Africa (SSA) has been identified as a future hotspot for food shortage due to current low agricultural yields and high population growth. Two important ways to improve yields are: A) Bridging dry-spells by implementing water harvesting for supplemental irrigation which results in more efficient use of the available green water and augmentation of the green water resource. B) Implementing productive sanitation systems, i.e. the collection of and safe reuse of human urine and faeces as a fertiliser for increased food production. In SSA the total amount of nutrients in excreta is roughly equivalent to the amount of nutrients applied as chemical fertilizers today. Productive sanitation systems can contribute to increasing the carbon content of the soil through increased plant productivity and thus increased input of leaf and root litter to the soil; it therefore represents a mitigation strategy for climate change. Water harvesting is a climate change adaptation strategy, since dry-spells are expected to become increasingly common under a future climate. Within the triple green project, we investigate the opportunities and challenges to increased crop productivity and food security through the use of productive sanitation in combination with water harvesting: producing higher yields (green) by adopting productive sanitation systems and supplemental irrigation, using green water more efficiently, in a sustainable (green) way. One of the key questions is thus whether the effect of combining these two management interventions is additive, multiplicative or perhaps only determined by the most limiting factor (water or nutrients). In addition, the following questions will be addressed within the project: (i) whether the use of a water harvesting approach is socially acceptable, (ii) whether the use of urine as a fertilizer may have potentially negative effects on salinity in the soil in arid climates, (iii) to what degree carbon sequestration takes place. In the second phase of the project the intention is to also include conservation agriculture, as an additional way of improving soil water holding capacity and soil carbon storage. If the results from combining these management interventions indicate significant long-term benefits in terms of yield, carbon sequestration and the ability to bridge dry-spells, the next step would be to repeat this set-up on the farmers’ field.
  2. 2. Human growth 20/80 dilemma Ecosystems 60 % loss dilemma Climate 550/450/350 dilemma Surprise 99/1 dilemma TThe Quadruple Squeeze
  3. 3. Dual challenge – environment and development • Meeting food requirements – MDG’s • Reducing atmospheric CO2 levels to 350 ppm
  4. 4. Climate Change Ocean acidification Ozone depletion Global Freshwater Use Rate of Biodiversity Loss Biogeochemical loading: Global N & P Cycles Atmospheric Aerosol Loading Land System Change Chemical Pollution Planetary Boundaries
  5. 5. Climate Change < 350 ppm CO2 < 1W m2 (350 – 500 ppm CO2 ; 1-1.5 W m2) Ocean acidification Aragonite saturation ratio > 80 % above pre- industrial levels (> 80% - > 70 %) Ozone depletion < 5 % of Pre-Industrial 290 DU (5 - 10%) Global Freshwater Use <4000 km3/yr (4000 – 6000 km3/yr) Rate of Biodiversity Loss < 10 E/MSY (< 10 - < 1000 E/MSY) Biogeochemical loading: Global N & P Cycles Limit industrial fixation of N2 to 35 Tg N yr-1(25 % of natural fixation) (25%-35%) P < 10× natural weathering inflow to Oceans (10× – 100×) Atmospheric Aerosol Loading To be determined Land System Change ≤15 % of land under crops (15-20%) Chemical Pollution Plastics, Endocrine Desruptors, Nuclear Waste Emitted globally To be determined Planetary Boundaries
  6. 6. Example - carbon sequestration in terrestrial ecosystems • Carbon sequestration by reforrestation • Carbon sequestration in agricultural soils • Improved water productivity by C- fertilisation What is the impact on water and food production?
  7. 7. Reforrestation An annual C seq rate of 1.6 GtC/yr by 2050 (Hansen et al) results in: • 1300 km3/yr increased consumptive water use by 2050 – reductions in runoff (trade-off) • If reforrestarion on current agricultural land: competition with food production (trade-off)
  8. 8. C seq on agricultural lands – Preliminary estimates An annual C seq rate of 0.4-1.2 GtC/yr by 2050 (Lal et al) results in: • 4000 – 10000 km3/yr increased consumptive water use by 2050 – reductions in runoff (trade-off) • NOT realistic – assumes same water productivity • Results in concurrent yield improvements (synergies)
  9. 9. Key question: Are the current agricultural techniques sufficient to meet this dual challenge?
  10. 10. The Triple Green project - Niger Agricultural management interventions for a new green revolution, in a green (sustainable) way based on green water, in the tropics Louise Karlberg, Linus Dagerskog, Elisabeth Kvarnström and Jens-Arne Subke Stockholm Environment Institute AND Moussa Baragé and Moustapha Adamou Abdou Moumouni University, Niamey, Niger
  11. 11. Triple Green - Rationale Small scale agriculture in SSA • Low yields • Erratic rainfall • Nutrient deficiency Possible to double or even triple yields
  12. 12. Triple Green - Methods Two important ways to improve yields are: A)Bridging dry-spells by implementing water harvesting for supplemental irrigation B)Implementing productive sanitation systems, i.e. the collection of and safe reuse of human urine and faeces as a fertiliser for increased food production. What are the added benefits of combining the two?
  13. 13. Triple Green – nutrients + water 0 50 100 150 200 250 Cropyieldimprovements(%) Non fertilised Fertilised CA WH WSD
  14. 14. Triple Green – climate change Mitigation: Productive sanitation + water harvesting systems can contribute to increasing the carbon content of the soil through increased plant productivity and thus increased input of leaf and root litter to the soil Adaptation: Water harvesting can help bridging dry- spells, which are expected to become increasingly common under a future climate.
  15. 15. Randomised block-trial on supplementary irrigated, urine fertilised millet
  16. 16. Expected results Field data will be combined with a physically based ecosystems model to study: • Carbon sequestration, water flows, yields and salt accumulation over time under different management regimes. Moreover, the model will be used to study the impact of a changed climate on these variables
  17. 17. Scaling out To answer this questions, we need: • Assessments across scales • Integrated assesments focussing on several sustainability criteria (e.g. nutrients, land-use, carbon and water) • A multi-sectoral approach (e.g. food, feed, fuel, fibre) • Assessments of ecosystem services, livelihoods, resilience, policies and institutions, etc. If implemented on a larger scale – would we produce enough food and still remain sustainable?

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