Producing more food with less water:

a global challenge

Eric OberBroom’s Barn Research Station

FAO Briefing paper: Hunger on the rise, Sep, 2008

FAO Food Outlook, November, 2008

“I wish to reaffirm that we know what needs to be done to eradicate the

hunger of 923 million people in the world. We also know what needs to be

done to double world food production and feed a population that is expected

to rise to 9 billion people by 2050. What we need ... is political will and

delivery on financial commitments, if we are to be able to make the essential

investments that are needed to promote sustainable agricultural

development and food security in the poorest countries of the world.”

--FAO Director-General Jacques Diouf, World Food Day, October, 2008

Challenges to global food production

• Climate change

• Competition with biofuels

• Soil fertility

• Input and commodity prices

• Availability of credit

CLIMATE CHANGE AND

FOOD SECURITY: A

FRAMEWORK DOCUMENT,

FAO, 2007

How does climate change affect crops?

• More CO2 and warmer temperatures will increase yields

• Greater evaporative demand and less rainfall

• Droughts will become more frequent and severe

• Increased probability and severity of heat waves

Month

1 2 3 4 5 6 7 8 9 10 11 12

Mo

nth

ly m

ax

imu

m t

em

pera

ture

(°C

)

0

5

10

15

20

25

30

Real (1976-2005)

Base

HI2020

HI2050

HI2080

By 2050 the maximum summertime temperatures

in East Anglia will have increased by 3 °C.

…and the amount of summertime rainfall

will have decreased.

How will future weather affect crop

production in the UK?

Scenarios

Baseline 2020HI 2050HI 2080HI

Su

ga

r yie

ld (

t/h

a)

0

5

10

15

20

Clay loam

Sandy

Sandy loam

Silt loam

Climate change effects on sugar beet

�Positive aspects

• Warmer Springs

• earlier sowing, faster canopy development, more light capture

• Increased CO2

• photosynthetic productivity

• Fewer winter freezing spells (-5°C)

• Less in-field frost damage

Climate change effects on sugar beet

�Negative aspects

• Less summer rainfall, drought stress

• Higher summer temperatures

• heat stress, increased Cercospora

• Warmer winters, increased pest survival

• More variable weather, extreme events

25-7-08

Insufficient water is the most important cause of yield loss in the UK beet crop

• Average potential evapotranspiration (June-Aug) for East Anglia = 350 mm H2O

• Average (June-Aug) rainfall = 150 mm H2O

• Average annual yield loss = 10%

• Jaggard et al. (1998) J Ag Sci 130: 337-43

Cost of drought to UK winter wheat production

• Annual losses (national average) of:

• 1-2 t ha-1

• >£ 40 million

• Foulkes et al. (2004) Proceedings of the 4th International Crop Science Congress, Brisbane, Australia

• 30% of wheat acreage grown on drought-prone land

• Increased demand for food

• Water availability limits yield

Increase rainwater catchment

Increase irrigation and irrigation

efficiency

Improve varieties

drought tolerance

water use efficiency

Improve soil fertility and water-

holding capacity

Research Objectives

• Identify genotypes with greater drought tolerance and water use efficiency (WUE) than current commercial varieties

• Identify traits that are associated with drought tolerance and WUE

• Develop screening tools that can be used by breeders to select superior varieties

• Use variety trial data to discover which current varieties show better drought tolerance or susceptibility

Some breeders’ experimental hybrids show better drought

tolerance than current commercial varieties

TS05

7.3 t sugar ha-1

3GR1810

5.6 t sugar ha-1

Characteristics of a successful drought tolerant variety

• Maintains productive foliage and delays

wilting and senescence

• Accesses more soil water

• Produces thinner leaves and cooler canopy

• Recovers growth faster following recovery

from stress

120 winter wheat genotypes grown under managed drought and irrigated conditions, 2008

Wheat genotypes show significant differences in drought tolerance

Drought tolerance index

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Num

ber

of

genoty

pes

0

5

10

15

20

25

LSD0.05 = 0.3***

Well watered grain yield (t ha-1)

2 4 6 8 10 12 14

Dro

ug

ht to

lera

nce ind

ex

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

r2 = 0.07

LSD

Drought tolerance does not necessarily demand a large penalty in yield potential

Select

Reject

CPBT W97

ExceptGatsby

Einstein

How to improve drought tolerance

Initial

crosses

Finished

variety

Screen for

secondary

traits

Evaluate performance

across multi-location

variety trials

Sta

bility

+

yie

ld p

ote

ntia

l

Varieties suited for

drought-prone land

Action

• Mitigation – adopting practices that reduce or remove greenhouse gas emissions • Analyse and improve your business’ ‘carbon footprint’

• Reduce nitrous oxide (N2O) emissions from soil N

• Look at what we grow and how we grow it

• Adaptation – making the changes necessary to be profitable in a changing environment• Invest in R&D

• Drought tolerance

• Disease resistance

Action-water resources

• Conduct ‘water use audit’

• Improve irrigation efficiency

• Decrease water waste

• Consider rainwater catchment, water

recycling

• Join local WAG, participate in CAMS

Action-water resources

• Irrigation efficiency• MOT equipment

• Check raingun pressure

• Use water meters

• Minimise wind effects

• Check uniformity

• Use scheduling

http://www.ukia.org

http://www.environment-agency.gov.uk/

“Weiji” = crisis

“Wei” = danger

“ji” = opportunity

Sponsors and collaborators: wheat

Sponsors and collaborators: sugar beet

Crop year

1975 1980 1985 1990 1995 2000 2005

Su

gar

yie

ld (

t h

a-1

)

0

2

4

6

8

10

12

14

16

Farmer delivered yield (111 kg/ha/yr)

Official variety trial yield (204 kg/ha/yr)

Sugar yields have been steadily increasing

Crop year

1975 1980 1985 1990 1995 2000 2005

Su

gar

yie

ld (

t h

a-1

)

0

2

4

6

8

10

12

14

16

18

Rain-fedIrrigated

Rainfed yields are more variable, and ~2 t less than irrigated yields.

Reasons for yield increases

• Improved varieties

• Better farming practices

• What about the weather?

Leaf wax score: 0 to 5

Genotypic diversity for waxiness

Climatic effects can explain much of recent

yield increases

kg sugar/ha per

year%

Total increase

(variety trials)204 100

Climate 114 56

Earlier sowing 25 12

Better varieties and

agronomy65 32

Since 1976……Conclusions

• Improved weather accounts for >50% of

the yield increase

• Earlier sowing was made often possible

because varieties/seeds have improved

• Better varieties/seeds account for >30% of

yield increase – mostly the variety effect

2006/07 2007/08 2008/09

Change: 2008/09

over

estim. f’cast 2007/08

million tonnes %

WORLD BALANCE

Production 596.6 610.5 677.0 10.9

Trade 113.3 111.2 119.0 7.0

Total utilization 619.2 615.8 643.3 4.5

Food 442.9 446.4 451.1 1.0

Feed 111.6 101.0 120.3 19.1

Other uses 64.6 68.4 72.0 5.3

Ending stocks 159.9 155.1 186.6 20.3

SUPPLY AND DEMAND INDICATORS

Per caput food consumption:

World (kg/year) 67.9 67.6 67.5 -0.2

LIFDC (kg/year) 58.4 58.1 58.0 -0.2

World stock-to-use ratio % 26.0 24.1 29.5

Major exporters’ stock-to-disappearance

ratio % 14.9 10.9 16.7

2006 2007 2008 Change:

Jan-Oct 2008

over

Jan-Oct 2007

Wheat Price Index %

(1998-2000=100) 145 216 302* 52

FAO Food Outlook, November, 2008

Wheat

• 70 per cent of all available freshwater is used for agriculture

• 0.5 t of water required to produce 1 kg grain or sugar

• >1 billion people lack access to safe drinking water

• Deficit in natural aquifers grows by 160 x 107 m3/yr

data: UNESCO

• Drought causes more crop losses than any other single biotic/abiotic factor

Boyer JS (1982) Science 218: 443-8

• United Nations

• International Decade for Action

Seasonal summed

water use

Water use efficiency (g kg-1

)

6 7 8 9 10 11 12

Lea

f D

elta

(p

art

s p

er

mil)

21.0

21.5

22.0

22.5

23.0

23.5

24.0

r2 = 0.42***

2005 Diallel Experiment-Glasshouse

Evaluating surrogate measures of water use efficiency

� 13C/12C discrimination ratio (∆) is negatively correlated with WUE.

Abouzar Rajabi and

Prof. Howard Griffiths,

U. Cambridge