Dr. Pasquale Steduto, Deputy Director Land & Water Division Food & Agriculture Organization of the UN. His presentation at The Water Network's event on Efficient Use of Agricultural Water in Zurich on January 23, 2013

1. Efficiency & Productivity
of Water in Agriculture
The conceptual framework
Pasquale STEDUTO
Deputy director
Land & Water Division
FAO, Rome

2. Drinking 2-4
Domestic 40-400
Food 1000-5000
Strong & Inextricable Link
between food and water
Roughly, 1 liter per Kcal

3. • Population growth
• Dietary changes
• Urbanization
• Income
• ………
• Progressive water scarcity (food water)
• Increased climate variability and change

4. Supply side
Expand arable land
Increase intensification
Yield
Increase Higher productivity
(77%)
Cropping
Intensity
Arable Land (14%)
Expansion
(9%)

5. Demand side
Reduce losses and waste
• In post harvest (storage, transport, market)
• At home EU, avg waste
of 179 kg p-1 y-1
Promote sustainable diets
• 1,400 M
overweight
• 400 M obese

6. Bio-fuels
Stocks reduction
Energy costs increase
Recurrent Droughts
………
Conducive to more crop and water
productivity (or water use efficiency)

7. e = out It is a-dimensional It has theoretical
in (input-output same units) limits (0-1)
It implies causality between input and output

8. It has specific units (e.g., Kg m-3)
It has no 0-1 limits
No causality between input and output

9. Wres_out/Wres_in
Wsoil-­‐stored/Wrain
Wfarm-­‐gate/Wres_out
Hydrology
Wcrop-­‐field/Wfarm-­‐gate
Wapplied/Wcrop-­‐field
Wroot-­‐zone/Wapplied
Wroot-­‐zone/Wsoil-­‐stored
Physiol.
Agron.
WET/Wroot-­‐zone
WT/WET
‘e’
CO2
assimil./WT
WP
Biomass/CO2
assimil.
Yield/Biomass

10. • Climatic environment • Genetics
Above-ground biomass (M ha-1)
- season shift - A/T
M5
- ET control - phenology
- CO2 enrichment (B) - canopy
M4 - roots
(A) - resistances
M3
M6
(D) M1
(A’) • Management
(E) - soil health
(C) M2 - fertility
- pest/dis/weed
E2 E1 ET1 ET2 - water
soil moisture
Evapotranspiration (ET, mm)
irrigation

11. technology
New varieties
management
Land & Water
climate Plant Nutrition
Pest & disease
From Sadras & Angus (2006)

12. Maize Productivity United States
China
Latin
America
Sub-Saharan
Africa

14. Relationship between WP & Yield
Water Productivity (Kg m-3)
Land Productivity (Kg ha-1)

19. statistics modeling RS
Socio-Econ.

20. • World food demand in 2050 = today x 2
• Without increase in water productivity, or a
significant reduction of the demand, water
consumption in 2050 = today + 70-90%
• The World is exposed to a progressive and
critical increase in water scarcity (+ climate
change)
• To respond to the future food demand we
need to act on both supply and demand side
of the food equation

21. • Without a comprehensive view of Y&WP, i.e.,
agronomy, technology, market, economy, etc.
the risks of failures in responses are high
• Assessing Y&WP variability, and related
causes, provides a strong basis for effective
policies and strategies of interventions, for
benchmarking and for monitoring progress
• This will provide better understanding of
what is “manageable” from what is not and
therefore prioritizing the policy measures
and implementation strategies

22. Thank You
www.fao.org/nr/water