Learning on the Run: Adaptive Salinity
Management in the South Australian
Lower Murray Region
Michael Cutting1, Tony Hoare2, Tapas Biswas3
1 South
Australian Murray-Darling Basin Natural Resources Management Board
2 Hoare Viticulture
3 Murray-Darling Basin Authority
Irrigation Australia Limited Conference - Adelaide, 2012
Presentation Overview
Rootzone salinity management study commenced in 2006/07
as a collaboration between the
South
Study
Area Australian Research &
Development Institute (SARDI) and the SA Murray-Darling Basin
Natural Resources Management Board
Finniss River
Water quality was an on-going issue for low yield wine grapes
Since study started significant changes have occurred over the
years: water source, water availability, water quality, water
taking rules
The presentation will highlight the value that on-going measuring
Murray Mouth
and
monitoring can assist on-farm decision making
Project Area (Regional) & Objectives
Study Area
Finniss River
1. How much salt
stays within the
root-zone from
summer irrigation
and what is its
distribution?
2. How does winter
rainfall move salts
within the profile?
River Murray
Hindmarsh Island
Project Area (Vineyard) & Statistics
Finniss River
Project Vineyard
Variety: Cabernet Sauvignon
Planting Year: 2002
Water Source: Finniss River/River Murray
Irrigation System: Conventional Drip
Flow Rate: 1.6L/hr
Emitter Spacing: 0.5m
Row Spacing: 3m
Plant Spacing: 1.5m
Application Rate: 1.1mm/hr
Soil Type: Sandy Clay Loam over friable
clay with occasional carbonate deposits
Rootzone Salinity Monitoring
Rootzone Salinity Monitoring with SoluSAMPLER™™
Extraction tube
0.3m
0.6m
PVC conduit
0.9m
Ceramic cup
Sentek TriSCAN™ (www.sentek.com.au)
The Finniss River: Flow vs. Salinity
The Finniss River Flow
30/05/2007
01/06/2007
System responds quickly to rainfall in
the Eastern Mt Lofty Ranges –
implications for salinity management!
Date
1/08/2007
18/07/2007
4/07/2007
20/06/2007
6/06/2007
23/05/2007
9/05/2007
25/04/2007
11/04/2007
28/03/2007
14/03/2007
28/02/2007
14/02/2007
31/01/2007
17/01/2007
3/01/2007
20/12/2006
6/12/2006
22/11/2006
8/11/2006
25/10/2006
Salinity (dS/m)
Irrigation Water Salinity – 2006/07 (Finniss River)
7
6
5
4
3
2
1
0
Rootzone Salinity - 2006/07
50
14.0
Irrigation
Rainfall
Soln 30cm
Soln 60cm
Soln 90cm
ETo
45
40
>Drip: water salinity = 5.5 dS/m
12.0
Big summer
rain event
Big winter rain
event
Irrigation/Rainfall (mm)
30
8.0
25
6.0
20
Winter
Leaching
Irrigation
Window
15
Summer
Leaching
Irrigation
Grape threshold salinity
10
4.0
2.0
5
0
1/07/06
0.0
1/09/06
1/11/06
1/01/07
1/03/07
1/05/07
1/07/07
1/09/07
EC (dS/m) or ETo (mm)
10.0
35
2007/08 - 2010/11: Dry Growing…not by choice!!
Impact of 2008 Heat Wave
Finniss River
March 2008
Rootzone Salinity 2007/08 – 2010/11
(No Irrigation)
60
50
14
12
Irrigation
Rainfall
ECsw 30cm
ECsw 90cm
8
30
6
20
4
10
2
0
1/07/2007
0
1/01/2008
1/07/2008
1/01/2009
1/07/2009
1/01/2010
1/07/2010
1/01/2011
EC (dS/m) or ETo (mm)
Irrigation/Rainfall (mm)
40
10
High levels of residual salts
still observed in 2007/08
ECsw 60cm
Rootzone Salinity - 2011/12
60
50
14
Irrigation
Irrigation water now sourced from River
Murray pipeline ~200EC (0.2 dS/m)
12
40
10
ECsw 30cm
259.2mm of
rain since
1 May 2012
ECsw 60cm
30
ECsw 90cm
8
6
20
4
10
2
0
1/07/2011
0
1/01/2012
EC (dS/m) or ETo (mm)
Irrigation/Rainfall (mm)
Rainfall
Rootzone Salinity Trend:
2006/07 – 2011/12
60
14
50
Average
rootzone
salinity =
10.9dS/m
Irrigation/Rainfall (mm)
40
Irrigation
resumed
~ 0.2 dS/m
No irrigation:
4 x seasons
12
10
Irrigation
Rainfall
ECsw 30cm
8
ECsw 60cm
30
ECsw 90cm
6
20
4
10
0
1/07/2006
EC (dS/m) or ETo (mm)
V. Poor WQ –
+ 6dS/m
2 Average
1/07/2007
1/07/2008
1/07/2009
1/07/2010
1/07/2011
rootzone
salinity =
0 1dS/m
Lessons & Conclusions
• Monitoring and managing root zone salinity is CRITICAL!
• Summer leaching irrigation largely ineffective in displacing
salts beyond the rootzone
• Very low leaching efficiency if water quality is poor
• Winter rainfall holds the key for salt displacement
• Leaching irrigation in winter can leach more salts with less
water
• Appears that salinity tolerance is enhanced and greater ability
to exclude salt under reduced yield production regime
Acknowledgements
SA MDB NRM Board
Mr. Tony Brooks (Vineyard Owner) - Strangers Reach
Vineyard, Finniss SA
SENTEK Sensor Technologies Ltd
Mr. Tim Pitt (SARDI)
Peter Zurcher (ex UniSA)