Coping with increased water scarcity: from “Efficiency” to “Productivity”
Theib Oweis Director, Integrated Water and Land Management Program, ICARDA, Amman, Jordan
Presentation at the 2014 Symposium: Drought in the life, cultures and landscape of the great Plains 1-4, April 2014. Lincoln, Nebraska
IWMI Colombo, Sri Lanka
CIFOR Bogor, Indonesia
ICLARM Penang, Malaysa
IRRI Los Banos, Philippines
ICRISAT Patancheru,
India
ICRAF Nairobi, Kenya
ILRI Nairobi, Kenya
IITA IBADAN, Nigeria
WARDA Bouake, Cote d’Iviore
Bioversity Rome, Italy
CIP Lima, Peru
CIAT Cali, Colombia
CIMMYT Mexico City, Mexico
IFPRI Washinton D.C., United States
ICARDA Aleppo,
Syria
Temperate dry areas
Water use per liter of biofuel production
Liters ET Liters irrigation
China
3800 2500
India 4100 3500
US 1750 300
Brazil 2250 200
Water scarcity intensifying
• 1/3 of the world’s population live in water scarce areas
• Many countries with chronic water scarcity
• Water for agriculture in dry areas is declining
• Climate change adds to the problems
• Energy competes • Consequences
85 8070
53
0
200
400
600
800
1000
1200
1990 2000 2025 2050
Cu
bic
met
er p
er c
apit
a
0
10
20
30
40
50
60
70
80
90
100
% o
f to
tal w
ater
res
ou
rces
% Agriculture share of totalTotal available water per capitaAgriculture share of water per capita
Southern Mediterranean
750
70008500
16000
1600
2000
4000
6000
8000
10000
12000
14000
16000
18000
Jordan Arab world World Europe North America
Pe
r ca
pit
a a
nn
ua
l m
3
Groundwater level (m below ground surface)Tel Hadya, Syria, 1983-2006
-110.0
-100.0
-90.0
-80.0
-70.01983 1986 1989 1992 1995 1998 2001 2004
New water … limited !!!!
Surface, mostly tapped Ground, over exploited Marginal-quality, small
amounts, environment, health Desalination, costly,
environment, transport Water transfer, cost and
politics
The context
Water & food Food security- self reliance- self sufficiency Virtual water imports More food needed / less water available Irrigation Efficiency: Can improvements
overcome water shortage? Modernizing irrigation systems? New directions & ned for change
Conventional coping strategies: insufficient !!!
Increasing yield: needs more water
Improving irrigation efficiency: only paper savings
Modernizing irrigation systems: The fallacy !!!
Demand management/ pricing water: not working in developing countries
Yield (t/ha)
ET (mm)
Typical furrow irrigation system
Storage
Irrigation
Precipitation
Field water balance
Runoff
Deep percolation Drainage
Seepage
Evaporation
Transpiration
Sprinkler irrigation
One can under irrigate No DP / 100% application Eff 50% storage Eff.
One can over irrigate 100% storage efficiency 50 % application efficiency
Trickle irrigation
• Under irrigation – Application eff. 100% – Storage eff. 50%
• Over irrigation – Application eff. 50% – Storage eff. 100%
Storage
Irrigation
Precipitation
Field water balance
Runoff recoverable
Transpiration
Evaporation Losses
To ground water recoverable
Deep percolation Drainage Partially recoverable Quality losses
Seepage recoverable
Issues of irrigation efficiency Reflects the performance of irrigation system
(engineering aspects) Ignores recoverable losses ??? Nothing to do with the return to water
(productivity) Wrongly used to judge the whole farm water
management system Huge investment in modernizing irrigation
Modernizing irrigation: water savings !
Does irrigation modernization save water ?
YES Does increasing Irrigation Efficiency from 50% to 80% save
30% water?
NO How much saving then? Depends on:
System changed and system adopted Irrigation management Crops and pattern Mostly in reducing evaporation and non beneficial use
Is it worth the cost? Not necessarily
Modern systems: productivity
• Higher productivity is not only associated with water savings. Drip irrigation does: – Provide better soil water due to frequent irrigation – Fertigation more frequent and uniform – Weed control
• The cost: – Investment, Maintenance, Skill – Salt accumulation needs periodical flushing
• Modernizing surface irrigation; ignored option
from efficiency
to productivity
Water productivity: the concept
Return WP = --------------------------------- Unit of water consumed
What return ?? Biomass, grain, meat, milk (kg) Income ($) Environmental benefits (C) Social benefits (employment) Energy (Cal) Nutrition (protein,
carbohydrates, fat)
What water ?? Quality (EC) Location (GW depth) Time available
Consumed (depleted) Evaporation Transpiration Quality deterioration
Biological WP kg/m3
0.03 0.3 0.2
3
10.4
0.1
1
7
3
0.81.2
0
1
2
3
4
5
6
7
8
Beef Lentil Wheat Potato Olive Dates
Economic Wp $/m3
0.1 0.1 0.10.3
10.8
0.3 0.30.6 0.7
3
1.6
0
0.5
1
1.5
2
2.5
3
3.5
Beef Lentil Wheat Potato Olive DatesNutritional WP Protein gr/m3
10
90
50 50
10 8
30
150 150
120
30
16
0
20
40
60
80
100
120
140
160
Beef Lentil Wheat Potato Olive Dates
Nutritional WP Calories/m3
60
1000660
3000
1150 1120
210
35004000
7000
3450
2240
0
1000
2000
3000
4000
5000
6000
7000
8000
Beaf Lentil Wheat Potato Olive Dates
Potential water productivity improvement
More food with less water
It takes a litre of water to produce every calorie, on average
Potential WP improvements
Reducing evaporation Improving management Enhancing genetic
resources Great potential in
developing countries
Scales and drivers to increase WP
At the basin level: competition among uses (Env., Ag.,
Dom.) conflicts between countries Equity issues
At the national level: food security hard currency sociopolitics
At the farm level: maximizing economic return Nutrition in subsistence farming
At the field level: maximizing biological output
Tradeoffs between water & land productivity
y = -0.4278x2 + 4.7328x - 0.543
R2 = 0.7611
0
5
10
15
20
0 2 4 6 8 10
Land productivtiy (t/ha)
Wat
er p
rodu
ctiv
ty (k
g/m
3 x1
0)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Tel Hadya Jinderis Terbol
Wat
er p
rod
uct
ivit
y (k
g g
rain
/ha-
mm
rai
n)
Spring-sown Winter-sown
0
0.5
1
1.5
2
2.5
Rainfed 33% SI 67% SI Full SI
Wat
er p
rodu
ctiv
ity
(Kg/
m3)
0
0.5
1
1.5
2
2.5
3
SI water FI water Rain water
Wat
er p
rod
uct
ivit
y (k
g/m
3) Supplemental irrigation water
Full irrigation water
Rain water
0
20
40
60
80
100
120
No intervention Micro WH Macro WH
% o
f ra
infa
ll
Evaporation Transpiration
0
0.5
1
1.5
2
2.5
N0 N50 N100 N150
Wat
er p
rodu
ctiv
ity
(kg/
m3)
Nitrogen application rate (kg N)
Rain water Irrgation water
Potential practices
Supplemental irrigation
Deficit irrigation Germplasm Cultural practices Water harvesting
CC alleviation potential of supplemental irrigation Crop yield based on GCM IPSL-CM4:
Yie
ld (
Mg
/ha)
2.0
4.0
6.0
------- Rainfed ------ Supplemental Irrigation
Ann. Precip: 334 322 287 260 334 322 287 260 mm
SI: 134 172 182 181 mm
Increase in irrig. water demand but also increase in yield and WUE!
Sommer, Hussein & Oweis 2011
Deg
rees
ce
ntig
rade
Temp
CO2
Conclusion
Business as usual
Thank you
