sugar cane irrigation from a research perspective ... · 25 november 2008. 2 1.introduction...
TRANSCRIPT
1
Sugar cane irrigation from a Sugar cane irrigation from a research perspective: research perspective: adapting to changeadapting to change
Ronald Ng CheongIrrigation Department
25 November 2008
2
1. Introduction
2. Managing demand
3. Managing resources
4. Conclusions
5. Acknowledgments
3
Introduction
4
Moving average annual rainfall
660
680
700
720
740
760
780
800
820
840
1962
-197
1
1964
-197
3
1966
-197
5
1968
-197
7
1970
-197
9
1972
-198
1
1974
-198
3
1976
-198
5
1978
-198
7
1980
-198
9
1982
-199
1
1984
-199
3
1986
-199
5
1988
-199
7
1990
-199
9
1992
-200
1
1994
-200
3
Year
Rainf
all (m
m)
1150
1175
1200
1225
1250
1275
1300
1963
-197
2
1965
-197
4
1967
-197
6
1969
-197
8
1971
-198
0
1973
-198
2
1975
-198
4
1977
-198
6
1979
-198
8
1981
-199
0
1983
-199
2
1985
-199
4
1987
-199
6
1989
-199
8
1991
-200
0
1993
-200
2
Year
Irrig
atio
n re
quire
men
t (m
m) Moving average
irrigation requirement
MÉDINE
5
Water Utilization in Mauritius
Purpose Surface Water(Mm3/yr)
Ground Water(Mm3/yr)
Total(Mm3/yr)
%
Municipal(domestic, industrialtourism)
86 123 209 21
48Agricultural 446 22 468
Hydropower 305 - 305 31
837 145 982 100Total
Source: WRU - 2001
6
Photo: Midlands Dam
Do we have enough storage capacity?
7
Evolution of water storage capacity in Mauritius
1885
Year of construction
Capacity(Mm3)
Purpose
25.891914 11.521929 5.261948 6.281952 2.99
- 2.30
- 0.60- 2.00
- 4.10- 4.30
2002 25.50
Mare aux Vacoas DomesticIrrigationLa FermeDomestic, irrigationLa NicolièreHydropower, irrigationMare LongueDomesticPiton du MilieuHydropower, irrigationTamarind FallsMill, irrigationValettaMill, irrigationDagotièreHydropowerEau BleueHydropowerCascadeDomestic, irrigationMidlands Dam
Total 90.74Domestic, Irrigation ??Bagatelle Dam 2010 ? ?
8
Increased competition – a realityTianli Integrated project
IRS projects
Managing water resourcesIRS project – Golf course
9
New concept: Maurice île durable
National programme on sustainable consumption & production for Mauritius (2008 – 2013)
Four strategies:1. Establish water efficient plumbing codes & regulations
2. Water efficiency audits in the agricultural, industrial &
commercial sector
3. Development of rainwater harvesting systems
4. Sustain a national awareness campaign on water savings
10
Managing demand
11
Approach 1:adopt more efficient irrigation systems
• Surface irrigation in early days
• Introduction of high pressure overhead in 1960’s
• Introduction of drip in 1970’s
• Adoption of pivot and dragline in 1990’s
12
Irrigation systems in Mauritius (Corporate planters)
DripDripIncreasing efficiency
Drip irrigation(10% of irrigated area)
Centre pivotCentre pivot
Overhead irrigation (85%)Centre Pivot (28%)Dragline (22%)Big Gun (35%)
DraglineDragline
Big GunBig Gun
Gated pipeGated pipeSurface irrigation(5% of irrigated area)
13
0
2000
4000
6000
8000
10000
1994 1996 1998 2000 2002 2004 2006Year
Are
a (h
a)
Surface Overhead
Recent evolution of less efficient systems
14
0
2000
4000
6000
1994 1996 1998 2000 2002 2004 2006Year
Are
a (h
a)
Dragline Centre pivot Drip
Recent evolution of more efficient systems
15
Future contribution of research
LEPA?
Linear move
Technical supporte.g. irrigation quality
16
Approach 2:Increase efficiency of irrigation systems
through better water management
Aim at a more rational management of waterresources.
Optimization of irrigation by maximizing water use efficiency (WUE) is therefore crucial.
17
WUE is the amount of marketable product per unit of water consumed (ton cane/ha/mm).
WUE is influenced by various factors:
• Irrigation system
• Level of management
• Water allocation
• Soil type
• Cropping system
To maximize WUE, supply of water to the crop must be based on a clear understanding of soil water dynamics.
18
Investigated temporal & spatial water distribution in the root zone with drip & pivot under estate management practice.
Minimize risk of irrigation water lost by runoff & deep drainage & improve WUE.
19
Objectives of trial:
• To gain an understanding of the soil water dynamics under drip and centre pivot systems.
• To assess drainage losses of both systems & toestimate their WUE.
• To study possibility of using generated data forirrigation scheduling.
20
Experimental details
Site : Union Vale, Mon Trésor S. E
Drip
Centre pivotSoil type : P2
Variety : M 1246/84
Cropping system : Dual row planting
Moisture sensors : Real-time monitoring system usingTime Domain Reflectometry (TDR)
Irrigation : Estate practice - soil moisture budget
21
TDR system & principles
CR 1000 Data logger
In-built circuit board
Stainless steel rods
CS 616 is calibrated to measure soil volumetric water content via dielectric constant measurements of the medium (capacity of medium to conduct electrical impulses).
Since dielectric constant of water (80) is large compared to soil matrix (<10) or air (1), small changes in soil water content affects the dielectric constant of the medium.
Battery operated & Ensures continuous
monitoring
CS 616 Water content
reflectometer
22
Soil water dynamics
Centre PivotCentre Pivot
0.05
0.15
0.25
0.35
0.45
30 40 50 60 70 80 90 100 110 120 130 140 150
0-20cm 20-40cm 45cm
02468
30 40 50 60 70 80 90 100 110 120 130 140 150
04080
120160
30 40 50 60 70 80 90 100 110 120 130 140 150
DripDrip
0.05
0.15
0.25
0.35
0.45
30 40 50 60 70 80 90 100 110 120 130 140 150
0-20 cm 20-40 cm 45 cm
Soil water content (v/v)
04080
120160
30 40 50 60 70 80 90 100 110 120 130 140 150
Daily rainfall (mm)
02468
30 40 50 60 70 80 90 100 110 120 130 140 150
Irrigation (mm)
30-Jan 01-Mar 01-Apr 01-May 30-MayCalendar days
23
Drainage losses
0
4
8
12
16
20
24
28
90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140
Rainfall C Pivot Drip
Rainfall and applied irrigation (mm)
0
10
20
30
90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140
C P ivo t Drip
Cumulative drainage (mm)
Calendar days
3 1 Ma r 10 Apr 30 Ap r 10 Ma y 2 0 Ma y2 0 Apr
24
Crop water use, yield & WUE
Effectiverainfall(mm)
Irrigationreceived
(mm)
Total wateruse
(mm)
Cane yield(t/ha)
WUE
(kg/ha/mm)
410 767 1177 110.2 94
560 511 1071 104.7 98
Drip
C. Pivot
25
Future contribution of researchIrrigation management under trash
blanketing in humid & sub-humid zones
Monitoring of soil moisture under trash & no trash using
CS 616 sensors
26
Approach 3:improve efficiency of existing system
• Verify application rate
• Control efficiency of system
27
Example
Audit of irrigation qualityDistribution tests under centre pivots & other systems
28
Indicator of irrigation quality:Christiansen’s uniformity coefficient
0
20
40
60
80
100
No. 1 No. 2 No. 2* No. 3 No. 4 No. 5
Pivot
CU (%
)
* Improved through de-scaling of drop tubes
29
Indicator of irrigation quality:Deviation from theoretical dose
0
50
100
150
200
250
No. 1 No. 2 No. 2* No. 3 No. 4 No. 5
Pivot
Dos
e ap
plie
d (%
)
* after descaling
30
Future contribution of research
Better management practicesEncourage proper record keeping
31
Approach 4:deficit irrigation
• Deliberate and systematic under-irrigation,leaving room in soil for rainfall
• Efficient use of limited water
• Irrigate larger areas to improve overall yield
• Sustainability
32
60
70
80
90
100
110
120
0
4
8
12
16Cane Sugar
100% 80% 60% RainfedTreatments
200
300
400
500
600
700
800
0
10
20
30
40
100% 80% 60%
Treatments
Water Used (mm) Water saved (%)
730
660
510
On-farm trial at Mon TrésorStudy effects of deficit irrigation on cane water use & yield
33
Possible use of water saved
TreatmentTreatment
80%80%
60%60%
VolumeVolume(Mm(Mm33/year)*/year)*
0.30.3
0.90.9
Area Area (ha)(ha)
Cane yieldCane yield(t/year)(t/year)
Expected Increases Expected Increases
* Based on a total irrigated area of 300 ha
3333 927927
130130 169169
34
Adoption of Deficit Irrigation at MTMD
After trial Before trial1997-1998 2000-2001 To-date
Water available (m3/h)
1300 1300 1500
Irrigated area(ha)
600 675 760
Irrigation applied
(mm/day)5.2 4.7 4.8
35
This strategy has been shown to work in the South
Applicability to be tested in other sub-humid areasthrough rainfall pattern, soil water measurements
Analyze Risks – recommend best practice
36
Managing resources
37
Possible approach:use of non-conventional water
• Wastewater from sugar factories
• Municipal wastewater
38
Factory wastewater for irrigation
• An important source of water for irrigation.
• At least 1 m3 produced per tonne of cane processed.
• Minimum of 5 Mm3 available per year.
• Can profitably be used to meet part of cane water requirement, especially in dry areas.
• Quality should comply with standards.
39
Governed by the Environment Protection Act 2002
The Environment Protection (Standards of effluent for use in irrigation) Regulations 2003Government Notice No. 46 of 2003
40
Some results of analysis of factory wastewater for irrigation Factory A
Parameters Range recorded
COD 90 - 19500 mg l-1 90
BOD 55 - 9200 mg l-1 30pH 3.9 - 6.8 5 - 9
Conductivity 210 - 2760 µS cm-1 2000
TSS 90 - 1230 mg l-1 45
Oil & Grease 12 - 25 mg l-1 no visible oil
SAR 1.3 - 5.2 6Cl- 24 - 220 mg l-1 250SO4
2- 6 - 120 mg l-1 500
Standards
Years: 1998 - 2000
41
Effects on irrigation systems - Corrosion problems(low pH & high Cl-)
Centre pivot pipesCentre pivot pipesHeavily corrodedHeavily corrodeddragline tripods
Corroded Corroded inside inside
dragline tripods
42
Monitoring of factory wastewater for irrigationFactory B
0
2000
4000
6000
8000
1-Jul 31-Jul 30-Aug 29-Sep 29-Oct 28-Nov 28-Dec
EC (m
icro
S/cm
)
4
5
6
7
8
9
10
1-Jul 31-Jul 30-Aug 29-Sep 29-Oct 28-Nov 28-Dec
pH
Reservoir Factory Field
43
Coping with high TSS (clogging hazards)
Filtration requirements
For drip systemUse sand filters for fine filtration (5µ)
For overhead systems
Screen FiltersEg EBS filters for high flow rates(1000 m3 h-1)
Disc Filtersfor medium flow rates(500 m3 h-1)
44
Coping with the corrosion problem1. At factory level:
•Avoid anaerobic conditions(acidity build up) in sedimentationponds (takes care of foul smell)
•Dilution with raw water(also alleviates problem of high TSS)
2. At field level:
•Flush system with fresh waterafter use
PVC line tube
•Use specially treated pipese.g. PVC line tube
Suspended PVC
45
Future contribution of research
Continue monitoring
46
Irrigation with municipal wastewaterIrrigation with municipal wastewater
47
• Treated effluent (tertiary level) is beingused for irrigation in the West
• 1:1 blending with fresh water
• Daily flow : 45 000 - 85 000 m3
48
Mixing of wastewater for irrigation
St Martin treatment plant
La Ferme canal
Magenta canalTo planters
To planters
Mixing pointSea
49
Water quality
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Mar-06 Jul-06 Oct-06 Jan-07 Apr-07 Aug-07
Month
pH
0
500
1000
1500
2000
Mar-06 Jul-06 Oct-06 Jan-07 Apr-07 Aug-07
Month
EC (M
icro
S/cm
)
Upper limit
Lower limit
Max. allowable
Source: WWMA
50
Water quality
Max. allowable
0
200
400
600
800
1000
Mar-06 Jul-06 Oct-06 Jan-07 Apr-07 Aug-07
Month
No.
faec
al c
olif
orm
s
Source: WWMA
51
0.0
0.5
1.0
1.5
2.0
Mar-06 Jul-06 Oct-06 Jan-07 Apr-07 Aug-07
Month
NItr
ate
N (p
pm)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Mar-06 Jul-06 Oct-06 Jan-07 Apr-07 Aug-07
Month
Tota
l P (p
pm)
Water quality
Source: WWMA
52
Future contribution of research
Incoming treated waste water
Water from Magenta Canal
53
Conclusions
54
•Situation is changing & we have to adapt to these changes
•We can manage demand or look for alternative resources
•The challenge is to remain innovative in the face of competition for water
•R & D can help to meet this challenge
55
Acknowledgments Managers & field staff of sugar estatesDirector, MSIRIColleagues at MSIRI:•M Teeluck•D Ratna•K Muthy
Last but not least -•D Ah-Koon