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Knowledge gaps trees, deep soil resources
and rainfed crop production in dryland
production systems
Jan de Leeuw
ICRAF Nai...
Revival of interest groundwater in Africa
• 2012 UCL Research 'Huge'
water resource exists under
Africa
• NERC-UPGRO: Unlo...
Perspectives on Agriculture in Sahelo
Soudanian Zone
• Crops – sorghum millet farming system
• Livestock – pastoral / agro...
Commodity based perspectives
• Agendas agriculture achieving DG’s
• Leading to focus agricultural institutions on
crop and...
Trees and multifunctional systems
• Agricultural systems can be managed to include trees to
optimize provisioning of multi...
The ecosystem goods: tree products
• Positives –
– Production of tree products more resilient to drought
than crops or liv...
Regulating service: Trees and
groundwater
• Hydraulic lift and
redistribution
groundwater
• Driven by gradient in
water po...
Supporting service: trees and soil fertility
• Nitrogen fixation associated to roots and moisture
• Redistribution nutrien...
Example Faidherbia alibida
• Groundwater dependent in drylands
• Widespread in Africa
• 5 million ha in Niger
• 0.5 millio...
Knowledge gaps nutrient enrichment and
hydraulic redistribution
• Biophysical principles well understood
• Significance an...
Trees and crops
• Positive impact on crop production
– Water balance – shade, hydraulic redistribution
– Nutrients – Upwar...
Trees and livestock
• Positive impacts –
– Food - foliage and seeds as forage for livestock
– Veterenary medicine – trees ...
Need for a strategic perspective on
groundwater and evergreen agriculture
• Reawakened interest developing
groundwater and...
Take home messages
• Trees enhance the production of the system as a
whole, benefits of this poorly recognized
• Trees sys...
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2014 05 bamako meeting jan de leeuw

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Transcript of "2014 05 bamako meeting jan de leeuw "

  1. 1. Knowledge gaps trees, deep soil resources and rainfed crop production in dryland production systems Jan de Leeuw ICRAF Nairobi
  2. 2. Revival of interest groundwater in Africa • 2012 UCL Research 'Huge' water resource exists under Africa • NERC-UPGRO: Unlocking Potential of Groundwater in Sub Saharan Africa • Renewed interest in development of irrigated agriculture • Argument this should not compromise benefits from agroforestry systems
  3. 3. Perspectives on Agriculture in Sahelo Soudanian Zone • Crops – sorghum millet farming system • Livestock – pastoral / agro-pastoral systems • Trees – dryland agroforestry system • Mixed systems: annual crops, livestock and trees • Agricultural institutions (incl. research) focus on crops and livestock • Do trees merit more attention?
  4. 4. Commodity based perspectives • Agendas agriculture achieving DG’s • Leading to focus agricultural institutions on crop and livestock commodities • Negative side – Monocultures – diet and health – Barren unhealthy landscapes – Unsustainable natural resource management
  5. 5. Trees and multifunctional systems • Agricultural systems can be managed to include trees to optimize provisioning of multiple functions: – Water and nutrients – Dietary diversity – Healthy human habitat – Food security / resilience – Sustainability • Trees build many of these traits into agricultural production systems, some are direct many are indirect benefits • Ecosystem service perspective on benefits from trees – Provisioning services, food and other goods – Supporting and regulating services
  6. 6. The ecosystem goods: tree products • Positives – – Production of tree products more resilient to drought than crops or livestock – Food fruits, nuts, edible oils also available dry season – Construction- and fuel-wood, gum arabica, assets than can be used in case of shortage • Negatives – – Prone to over-utilization and degradation – Trees in the landscape are a fragile natural capital
  7. 7. Regulating service: Trees and groundwater • Hydraulic lift and redistribution groundwater • Driven by gradient in water potential • Moisturizing dry upper soil horizons • Benefiting shallow rooted species like crops
  8. 8. Supporting service: trees and soil fertility • Nitrogen fixation associated to roots and moisture • Redistribution nutrients from lower soil horizons
  9. 9. Example Faidherbia alibida • Groundwater dependent in drylands • Widespread in Africa • 5 million ha in Niger • 0.5 million ton increased cereal production • 1 million people benefiting • Are these benefits attributable to groundwater? • What is the potential for upscaling and how does that relate to groundwater?
  10. 10. Knowledge gaps nutrient enrichment and hydraulic redistribution • Biophysical principles well understood • Significance and benefits of poorly not quantified • Potential for designing more resilient agricultural systems to be explored
  11. 11. Trees and crops • Positive impact on crop production – Water balance – shade, hydraulic redistribution – Nutrients – Upward redistribution, N fixation • Negative impacts on crop production – Competition for water and nutrients • Gap - optimal design of tree - crop systems
  12. 12. Trees and livestock • Positive impacts – – Food - foliage and seeds as forage for livestock – Veterenary medicine – trees important • Negative impacts – – Livestock degradation tree cover and the sustainability of benefits derived from trees • Gap – designing sustainable integration of tree based forages and crop residues in livestock production systems
  13. 13. Need for a strategic perspective on groundwater and evergreen agriculture • Reawakened interest developing groundwater and irrigation • Danger of development of irrigated agriculture ignoring benefits from AF systems • Blue water paradigm dominates groundwater management • Paradigm shift required towards blue and green water management • Evidence required that trees in Sahelian landscapes generate significant social benefits
  14. 14. Take home messages • Trees enhance the production of the system as a whole, benefits of this poorly recognized • Trees system builders, multifunctional landscapes with many desirable traits including support to crop and livestock production • Research lacking on optimization and design of multifunctional landscapes and the role of trees in there
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