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Third International Symposium On Soil Water Measurement Using

Capacitance, Impedance and Time Domain Transmission

Murcia, SpainApril 7-9, 2010

Managing the Soil Water Environment to Meet Growing

Food DemandsFood Demands

Keynote Presentation by Chandra A. Madramootoo

Professor McGill UniversityProfessor, McGill University and President, ICID

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High variant

Global Population 1960 Global Population 1960 -- 20502050

12

14

billion

Medium variant

Low variant

6

8

10

1960 1970 1980 1990 2000 2010 2020 2030 2040 20502

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Year

FOOD PRODUCTION NEEDS TO DOUBLE OVER THE NEXT 25 YEARS TO MEETYEARS TO MEET POPULATION DEMANDS

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Food ShortagesFood Shortages

Over one billion remain malnourishedOver one billion remain malnourishedOver one billion remain malnourishedOver one billion remain malnourishedClose to 800 million in less developed Close to 800 million in less developed countriescountriesWorld Food Summit World Food Summit reduce by 50% reduce by 50% by 2015by 2015N d d b 22 illi /N d d b 22 illi /Need to reduce by 22 million / yrNeed to reduce by 22 million / yrCurrent rate Current rate –– 6 million / yr6 million / yr2.8 billion people earn $2 or less2.8 billion people earn $2 or less

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Global Irrigated and Rainfed Cropland Statistics

• 1 500 million ha of global cropland• 1,500 million ha of global cropland• 275 m ha irrigated (17%)• Irrigated lands produce 40% of

world’s food• 1,250 m ha of rainfed lands

producing 60% of the world’s food

Main dietary food sources

Source: FAOSTAT 2003 summarized by UNESCO-WWAP. 2006

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Freshwater availability per capita 1950- 2050

9%

Water use by sector,2000

71%

20%

71%

Agriculture Industry Domestic

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Advent of the Green Revolution – 1970s

Region Irrigated Area Share of Share of CroplandWorld Total* That is Irrigated

(Milli h ) (P t) (P t)

World Irrigated Area by RegionWorld Irrigated Area by Region

2004 2004

(Million ha) (Per cent) (Per cent)

Asia + 193.9 70 33North and Central America 31.4 11 12Europe 25.2 9 8Africa + 12.9 5 6South America + 10.5 4 8Oceania 2.8 1 5----------------------------------------------------------------------------------------------------------------------World 276.7 100 18

+ Scope for irrigation expansion+ Scope for irrigation expansion..

FAOSTAT, 2004 FAOSTAT, 2004

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(Pardey, 2009)

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Rehab, maintenance, upgrading

Improved On Farm Water Management

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Investments in water savings irrigation technologies

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Furrow Irrigation Efficiencies(Rice et al., 2001)

Irrigation Efficiency GainsIrrigation Efficiency GainsOn-Farm Reservoir Evaporation

Conveyance Works

4.5% of gross diversion

Return Flow

0% of gross diversion

1.2% of gross diversion 14% of gross diversion

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Today we use 30% less water to grow a crop than we did 25 years ago.

OTHER POSITIVE BENEFITS TO WATER CONSERVATION

• Reduced water quality impairmentR d d li it d t l i• Reduced salinity and waterlogging

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IRRIG, PRECIP

ET

Surface runoff

Leaching Fraction

Manage the soil water reservoir

Soil Water Reservoir

runoffActive root zone

Capillary fluxes

Return flows

(Q,L)Capillary fringe

Percolation

GW accretionUpward GW movement

Interflow

Capillary fluxes

Subsurface drainage

Return flows (Q,L)

Capillary fringe

TRADITIONAL METHODS OFMETHODS OF

SOIL MOISTURE

MONITORING

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Gro-Points

H t t i tCapacitance probes

Hortau tensiometers

Irrigation scheduling of tomatoesin Southern Ontario

-South western Ontario/ Canada

Leamington site

South western Ontario/ Canada

-Climate and soils-suitable for tomatoes

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Investigating the effect of different irrigation triggers on crop yield and quality

For Surface and Buried Drip Systems

Loamy sand86% sandFC – 21%WP – 9%

Three different soil moisturemonitoring devices werepermanently installed tocollect continuous data

Soil Moisture Instrumentation

Campbell Scientific CS625 water content reflectometer

The enviroSCAN–Capacitance Probe

The wireless electronic tensiometer (Hortau).

WR

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Calibration curve for Frequency Domain

Reflectometer

y = -0.434x2 + 26.13x - 359.0

30

32

30.00

32.00

Calibration Curve for Water content Reflectometer

Greehouse Experiment

100 % Field Capacity

R² = 0.99

y = 2.678x - 42.62R² = 0.975

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26

28

24.00

26.00

28.00

VW

C (%

)

75 %  Field Capacity (22.5 %VWC & 24.95 μSec)

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20

22

18.00

20.00

22.00

23.5

23.6

23.7

23.8

23.9

24.0

24.1

24.2

24.3

24.4

24.5

24.6

24.7

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24.9

25.0

25.1

25.2

25.3

25.4

25.5

25.6

25.7

25.8

25.9

26.0

26.1

26.2

26.3

26.4

26.5

26.6

26.7

26.8

26.9

27.0

27.1

27.2

27.3

27.4

27.5

Periods μSec

VWC_m % %FC 75%FC Poly. (VWC_m %) Linear (VWC_m %)

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0.85

0.90

Soil Moisture trends for Surface Plot 44Treatment -70%FC - August

0.65

0.70

0.75

0.80

SFU

0.50

0.55

0.60

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01/09

Month of August 2008

SFU44_10_Avg SFU44_20_Avg 70% Trigger 100% FC

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The Research Challenge: Where to install sensors and to what depths?

Can we manage and save water? From point to complex heterogeneous systems

Geospatial and computational analysis

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Fourth International Symposium On Soil Water Measurement Using

Capacitance, Impedance and Time Domain Transmission

THANK YOU