Presentation from the WCCA 2011 event held in Brisbane, Australia.

1. 5th World congress of conservation agriculture
Incorporating 3rd farming systems design conference
Irrigation performance and seasonal changes under
permanent raised beds on Vertisol in Queensland,
Australia
Ghani Akbar (NCEA, USQ Toowoomba, Qld)
Professor Steven Raine (FOES, USQ Toowoomba, Qld)
Dr Allen Jack McHugh (NCEA, USQ Toowoomba, Qld)
Mr Greg Hamilton (Maximum Soil & Water Productivity Pty Ltd. Perth WA)
26 to 29th September, 2011
1

2. Introduction
Major Agricultural Challenges
Land Water Use
Water Scarcity
Degradation Efficiency
Issues
Issues Issues
Population Intensive Irrigation
growth cultivation management
Inefficient
Seasonal Agronomic
irrigation
changes management
systems
2

3. 1. Water Scarcity Issues
a) Population
- Population growth increase pressure on
available water resources
- (2000-5000 Litres/day) is required to support
a single person diet
Figure : Global water withdrawal by sector
Source: WWI from P.H. Gleick (1993),Water in crisis, Oxford University Press
b) Inefficient irrigation systems
- Only 20% global cultivated land is irrigated
- Irrigated lands produce 40% world food
- Utilise 70% of global water withdrawal
- Inefficient & poor irrigation management
(There is need for the efficient use of available water Figure : Percentage of cultivated area equipped for irrigation
to meet the growing food, fibre & domestic needs) Source: FAO-AQUASTAT
Introduction 3

4. 2. Land Degradation Issues
a) Intensive cultivation
- Damages soil physical, chemical and
biological health
- Causes erosion, crusting, sealing, loss of OM
& nutrients thus productivity decline
Intensive cultivation
b) Seasonal changes
- Wetting, flowing water, rainfall hammering
slaking, shrinking, swelling & subsidence
Fresh bed
Subsided bed
- Affect soil hydro-physical properties which
also affect irrigation & crop performance
- Maintenance cost also increase
( There is a need for adoption of soil friendly
Seasonal changes
agronomic practices for improving soil health
& stability on sustainable basis)
Introduction 4

5. 3. Water Use Efficiency (WUE) Issues
• WUE is a generic term used for indicating water use in crop production.
(GPWUI, IWUI, CPWUI,...) (Burett Purcell & associate, 1999)
a) Irrigation management
• Type of irrigation system Irrigation Agronomic
Issues Issues
• System efficiency & uniformity
(Ea, Er, DU etc)
b) Agronomic management
Water Use
• Land management & tillage Efficiency
• Cropping management
• WUE improvement is the key for producing more food with less water
(Under the prevailing water scarcity and declining land productivity situations
WUE improvement on sustainable basis is essential for future food security)
Introduction 5

6. Research opportunities
• Past NCEA studies identified furrow irrigation (Ea) 30-60% and reasons were
attributed to excessive deep drainage losses, poor irrigation management
and field design issues. They identified 85-95% achievable (Ea) by better
irrigation management & field design.
(Raine & Bakker, 1996; Smith et al. 2005)
• Similarly improved soil amelioration (i.e. better structure, porosity, hydraulic
conductivity) were reported under the rain-fed Vertosol soil condition by
adopting zero till control traffic farming.
(Tullberg, 1988, McGarry, 2001, McHugh et al. 2003)
• However, evaluation of current PRB farming system affected by variable bed
furrow configurations, soil management, subbing and their impact on
irrigation management strategies were rarely considered.
Literature Review 6

7. Objectives:
Evaluate the irrigation performance of
existing PRB farming systems under
Australian vertisol soil conditions
To identify potential for lateral wetting
front infiltration from furrow to centre of
bed
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8. Methodology
 Field trials:
Site 1: Marinya farm, Cambooya (Soybean)
Site 2: Bandawing farm, Dalby (Cotton)
 Data collection
 Tillage and field information
 Irrigation inflows Advance Sensors
 Flow advance along furrows
 Runoff at tail end
 Furrow geometry & slope
(Use of IRRIMATETM tools)
 Use of IPARM & SIRMOD for performance evaluation
Flume with flow meter
 Soil moisture movement across the bed (Using
assembly of Sentek (Enviroscans) for lateral wetting
front infiltration (Cambooya)
 Use of SIRMOD for irrigation performance optimization
(Er≥ 85%, Water arrival to furrow tail, maximum water saving)
Siphon with flow meter
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9. Layout of Sentek (enviroscans) sensors placed across
the bed for logging wetting front penetration into bed
centre at Marinya farm Cambooya
Methodology 9

10. Results 1200
1000
Advance time (min)
Irrigation 1
800 Irrigation 2
Site 1:
Irrigation 1: Narrow 600
furrows, loose soil
400
Site 2:
200
Irrigation 2: Cracking due 0
dry soil conditions
200 0 100
300 400 500
Distance along furrow (m)
Figure: Measured advance curves of two irrigations to soya bean at Marinya
farm Cambooya (bars shows +/- standard deviation)
700
Irrigation 1
Flow advance time (min)
600 Irrigation 2
500
400
300
200
100
0
0 100 200 300 400 500
Distance along furrow (m)
Figure : Measured advance rate during two irrigations of cotton crop at
Bandawing farm, Dalby (bars shows +/- standard deviations)
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11. Figure : Cotton crop at Bandawing farm near Dalby with (a)
measured irrigation 1; (b) measured irrigation 2 with flow crossing
the bed through cracks due to dry soil conditions
Results 11

12. Table : Impact of irrigation management strategies on current irrigation performance of
two sites under black cracking Vertisol soils in southern Queensland, Australia, (values in
brackets are +/- standard deviation).
Water
Q Tco Ea Er Inflow
Site Strategies DU (%) saving*
(L.s-1) (min) (%) (%) (m3/ha)
(%)
Farmer 1.94 1100 73 100 90 1393
managed (0.1) (61) (6) (0) (3) (113)
Cambooya
1. Tco 1.94 921 80 92 74 1167
16.2
optimised (0.1) (84) (8) (2) (3) (137)
2. Tco & Q 3.25 425 98 85 88 879
37
optimised (0.7) (88) (1) (0) (3) (11)
Farmer 2.54 635 79 97 87 1062
managed (0.1) (64) (8) (2) (1) (84)
Dalby
1. Tco 2.54 473 97 88 77 790
25.6
optimised (0.1) (121) (1) (3) (2) (186)
2. Tco & Q 3.125 370 97 85 82 762
28.3
optimised (0.2) (40) (3) (0) (4) (125)
*Water saved as compared to farmer practice
Results 12

13. Figure : Relationship of optimum Tco vs. Q, average values of two
irrigations, with predicted irrigation performance (Ea, Er and DU) at two sites.
Results 13

14. 4.50
1 L/s
4.00 2 L/s
3 L/s
3.50
4 L/s
3.00 5 L/s
Tco/Ta
2.50
2.00
1.50
1.00
0.50
0.00
0 100 200 300 400 500 600
Furrow length (m)
Figure: Effect of furrow length and inflow rate on
the ratio (between time to cut-off and time of
advance to tail end) for achieving Er≥ 85% and flow
arrival at tail end (Cambooya: irrigation 1).
Results 14

15. Figure : Temporal and spatial variations in lateral water infiltration across 2 m wide
bed at (a) 33cm, (b) 67cm and (c) 100cm from furrow centre during summer 2010
(soya bean) at Cambooya, Qld, Australia.
Results 15

16. Conclusions
The current irrigation management is not optimal , often longer Tco and lower Q
than optimal are practiced under farmer managed conditions.
Majority of current soil management/raised bed renovation practices are not
optimal leading to low irrigation performance and poor water use productivity.
The current bed furrow configurations are largely not optimal causing poor
irrigation performance and crop establishment leading to low WUP.
Subbing is not a significant problem under the current irrigation management of
Australian farms with lengthy furrows and prolonged irrigation cut-off times but
can affect crop performance especially at tail end if infiltration opportunity time is
not sufficient (i.e. <5 hours in the case evaluated).
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17. Data recording Bulk Density and soil moisture data
1st Irrigation at Cambooya 2nd irrigation Soybean crop
The End
Thanks all of you
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