1. Rainwater Management for Increased Agricultural production Centre of African Studies – Porto- Portugal 2 – 3 October 2008 CONFERENCE ON WATER IN AFRICA SESSION ON WATER AND AGRICULTURE Nico van Leeuwen

3. < 2.5 2.5–4 5–19 20–34 ≥ 35 No data % undernourished UNDERNOURISHMENT

5. < 2.5 2.5–4 5–19 20–34 ≥ 35 No data % undernourished UNDERNOURISHMENT SUB- SAHARA AFRICA

7. < 2.5 2.5–4 5–19 20–34 ≥ 35 No data % undernourished Undernourishment and water scarcity Sub- Sahara Africa

8. Dry land areas and rain fed agriculture Arid land: 45% of world area, 38% of Sub-Saharan Africa

9. Strong relationship between water availability and cereal production

12. Arable land expansion 22 % Cropping intensity 12 % How to grow 50 % more food in 2030 Yield increase 66 %

16. (Rockström, Fox, Persson et Falkenmark(SIWI) RAINWATER MOVEMENTS

17. Rainwater distribution in arid areas (Rockström, Fox, Persson et Falkenmark(SIWI)

20. Small-scale conservation agriculture

21. Permanent soil coverage

22. Mechanized conservation agriculture

24. Potential areas for runoff farming Source: GAEZ (FAO – IIASA, 2003) > 800 mm 400 < x < 800 mm 200 < x < 400 mm 100 < x < 200 mm < 100 mm Annual rainfall > 179 days Too wet for runoff farming > 0.65 Humid 120 – 179 days Suitable for runoff storage 0.5 – 0.65 Dry sub- humid 60 – 119 days Suitable for runoff farming 0.21 – 0.5 Semi- arid 1 – 59 days Suitable for runoff farming 0.05 – 0.2 Arid 0 day Too dry for runoff farming < 0.05 Hyper arid Length Growing Period Suitability P/ETP Zone

25. Microcatchment Macrocatchment Floodwater harvesting Types of run-off farming water harvesting

26. Small-scale rainwater harvesting (zai)

27. Tree planting for reforestation or land rehabilitation

28. Inter-row water harvesting in orchard in arid area

31. Mechanized runoff farming

33. Keita project Niger

34. Keita project Niger

35. 1 3 1 3 2 Example: Keita (Niger) 2

38. Rainwater management: a new green revolution ? Thanks for your attention Merci pour votre attention Obrigado