Efficiency & Productivity of Water in Agriculture The conceptual framework

Pasquale STEDUTO Deputy director

Land & Water Division FAO, Rome

Drinking 2-4 Domestic 40-400 Food 1000-5000

Strong & Inextricable Link between food and water

Roughly, 1 liter per Kcal

•  Population growth •  Dietary changes •  Urbanization •  Income •  ………

•  Increased climate variability and change • Progressive water scarcity (food water)

Yield Increase

(77%)

Cropping Intensity

(14%) Arable Land Expansion

(9%)

Supply side Expand arable land Increase intensification Higher productivity

•  In post harvest (storage, transport, market)

•  At home

Promote sustainable diets

EU, avg waste of 179 kg p-1 y-1

Reduce losses and waste

•  400 M obese

•  1,400 M overweight

Demand side

Bio-fuels Stocks reduction Energy costs increase Recurrent Droughts ………

Conducive to more crop and water productivity (or water use efficiency)

It is a-dimensional (input-output same units)

It has theoretical limits (0-1)

It implies causality between input and output

e = out in

It has specific units (e.g., Kg m-3)

It has no 0-1 limits

No causality between input and output

Wres_out/Wres_in  

Wfarm-­‐gate/Wres_out  

Wcrop-­‐field/Wfarm-­‐gate  

Wapplied/Wcrop-­‐field  Wroot-­‐zone/Wapplied  

Wsoil-­‐stored/Wrain  

Wroot-­‐zone/Wsoil-­‐stored  

WET/Wroot-­‐zone  

WT/WET  

Hydrology  

Agron

.  Ph

ysiol.   CO2  assimil./WT  

Biomass/CO2  assimil.  

Yield/Biomass  

‘e’

WP

•  Climatic environment - season shift - ET control - CO2 enrichment

M6

M1

M3

M4

Abov

e-gr

ound

bio

mas

s (M

ha-

1 )

Evapotranspiration (ET, mm)

(A)

(B)

(C)

(E) (D)

ET1 ET2

M5

(A’)

•  Genetics - A/T - phenology - canopy - roots - resistances

•  Management - soil health - fertility - pest/dis/weed - water soil moisture irrigation

E1 E2

M2

management

Plant Nutrition Land & Water

Pest & disease

technology New varieties

From Sadras & Angus (2006)

climate

United States

China

Latin America

Sub-Saharan Africa

Maize Productivity

Wat

er P

rodu

ctiv

ity

(Kg

m-3

)

Land Productivity (Kg ha-1)

Relationship between WP & Yield

stat

isti

cs

mod

elin

g RS

Socio-Econ.

•  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

•  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

www.fao.org/nr/water

Thank You