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4/16/2010
1
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
4
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
24
26
28
24.00
26.00
28.00
VW
C (%
)
75 % Field Capacity (22.5 %VWC & 24.95 μSec)
18
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
24.8
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
01/08
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31/08
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
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