Water Use Efficiency and Agronomic Techniques for Water Saving marzo/water/water.pdf · Agronomic...
Transcript of Water Use Efficiency and Agronomic Techniques for Water Saving marzo/water/water.pdf · Agronomic...
4th World Water ForumMexico march 16-22, 2006
Special session on« WUE in Agriculture and Potential for Water Saving in the Middle East Region »
CIHEAM/IAM-B
Water Use Efficiency and
Agronomic Techniques for Water Saving
Netij Ben MechliaInstitut National Agronomique de Tunisie- Tunisia
Precipitation Renewable (m3/cap.) (m3/cap.)(Km3) (Km3) (2000) (2025)
Algeria 163 14 450 300
Morocco 150 30 1000 800
Tunisia 34 4 450 300
Water Resources in North Africa
Cultivated and irrigated areas in North Africa (million ha)
Algeria Morocco Tunisia
Cultivated 8.0 9.6 4.9
Irrigated .6 1.3 .4
A fundamental relationship between production (W) and transpiration (T) is:
W = mT/ETo
ETo is a measure of evaporative demand andm is a crop constant, (100-200Kg/ha/day)
for Efficient Water Use in Crop Growth (W) :
• Maximize m- select species of large m
• Maximize T- store water on appropriate soils- deep roots to extract all water- weed control, mulching- rapid crop growth
• Minimize ETo- select locations with small ETo- grow at times of year when ETo is small
Further requirements for yield (Y):
- maintain T for duration of crop cycle.
- avoid stresses at vulnerable times for yield formation.
- seek optimum balance of water use during vegetative and reproductive phases.
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ETa (mm)
Yiel
d (q
t/ha)
Rainfed
Irrigated
1. Supplemental Irrigation
yield of wheat under S. I. and Rainfed conditions
2. Water harvesting
WH has an advantage if :
• Soil has good water-holding capacity.• Crop relies on stored water.
When
Rainfall is infrequent.Lasting drought is probable
3. Deficit Irrigation
the rationale of DI is to reduce irrigation during periods of vegetative growth of plants, thus effects on yield are minimized.
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PrimeurSaisonArrière saison
Ren
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ent r
elat
if (Y
/Y10
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Réduction de l'irrigation (%)
Deficit irrigation of Potatoes
Deficit Irrigation of Peach Trees
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Y/Yo
Irr. Deficit (%)
DI-Spring
DI-Summer
DI-Continuous
Full Irrigation
4. Inter Cropping: adjusting cropping systems to unreliable water supply
R1
R2 R4
R3
Rainfall
ETR
Irrigation
Assessment of water harvesting and supplemental irrigation potential in arid and semi-arid areas of West Asia and
North Africa
Assessment of water harvesting and Assessment of water harvesting and supplemental irrigation potential in arid supplemental irrigation potential in arid and semiand semi--arid areas of West Asia and arid areas of West Asia and
North AfricaNorth Africa
< 200 mm200-400 mm400-600 mm600-800 mm800-1000 mm1000-1200 mm> 1200 mm
PrecipitationPrecipitation mapmap
Capability of the methodology developed to identify hill reservoirs potential sites
Validation of the methodology using ASTER 2003Validation of the methodology using ASTER 2003
MappingMapping oliveolive--MeskatMeskat usingusing LandsatLandsat ETM imageETM image
Re f
l ec t
anc e
Bands
Subset Unsupervisedclassification
Landsat ETM Image 06 March 2002
RGB 453
Olive Class
00.10.20.30.40.5
ETM1 ETM2 ETM3 ETM4 ETM5 ETM7