Redirecting rain to manage soil salinity:
Lessons from groundwater and recycled wastewater irrigated vineyards
Tim Pitt, Rob Stevens, Jim Cox and Mike McCarthy
SARDI – Water Resources, Viticulture & Irrigated Crops
4 June 2014
Outline
Salinity and yield response
Project Background
Proof of concept – Padthaway (Groundwater)
Pre-trial investigations
Hypothesis
Results
Adelaide
McLaren Vale
Padthaway
Pilot study – McLaren Vale (Recycled Wastewater)
Progress
Summary
Mt Gambier
Salinity and Yield Response
1000EC
= 1000µS/cm
= 1dS/m = 640mg/L
= 1mS/cm
= 640ppm
Salinity and Yield Response
120
100
Grape yield decline threshold
Relative Yield (%)
~2.1 dS/m (1340 ppm)
80
60
40
20
0
0
2
4
6
ECe (dS/m)
8
10
Project Background
2007 – 2009 salinity project developed for South East SA
Emerging salinity damage
Downward trend in rainfall
Increasing groundwater salinity
Introduction of regulated allocations
2010 – 2012 ‘Proof of concept’ trial
AIM – to identify techniques to manage
rootzone salinity in vineyards receiving
supplementary saline ‘groundwater’ irrigation
Proof of Concept
Padthaway:
Adelaide
Wine grape (Chardonnay)
Sandy loam to clay over limestone
Padthaway
Groundwater irrigation ~1.9 ML/yr
Groundwater Irrigation ~2.2 dS/m (1400 ppm)
Mt Gambier
Proof of Concept
Pre-trial measures 2009
Salt symptoms in vines, petiole Cl- = 1-1.5 % (toxic)
Salt and sodicity distribution across vineyard floor
10
20
8
16
6
12
Salinity higher UV than in MR
SAR
ECe (dS/m)
Salinity
Sodicity
4
8
2
4
0
0
Under-vine
Mid-row
Sodicity higher UV than in MR
Infiltration >30 mm/hr at
both points
Proof of Concept
Average rootzone
salinity under-vine
ECe (dS/m)
Average rootzone
ECe (dS/m)
10
8
6
4
2
Yield
decline
threshold
0
(mm)
(mm)
60
40
Rain
Irrigation
20
0
Nov-08
May-09
Autumn
Nov-09
Spring
May-10
Autumn
Winter rain flushing salt from rootzone
High SAR under-vine not impeding infiltration
Nov-10
Spring
Proof of Concept
Hypothesis
Re-distributing rain falling on the mid-row to under the
vine will reduce rootzone salinity
Proof of Concept
Soil EC
Plant Na+ and ClYield components
Vigour
Proof of Concept
4.1 dS/m
Results
2.5 dS/m
Reduced under-vine soil salinity by 40%
Proof of Concept
Results
Re-directing rain from mid-row to under-vine soils:
• reduced juice Na+ by 25 % and Cl- by 40 %
Rain re-directed from midrow to under-vine?
Juice
Na+ (mg/L)
Cl- (mg/L)
Vintage
2010
2011
2012
No
46
33
28
Yes
2010
138
-
2011
2012
72
59
-
28 *
18 **
49 *
29 **
* < 0.05
** < 0.001
Proof of concept
PROBLEM
Treatments are NOT
commercially viable!!
Pilot study
Will more commercial treatments
be as effective?
A
C
B
D
E
Pilot Study
McLaren Vale:
Wine grape (Cabernet Sauvignon)
Adelaide
McLaren Vale
Clay loam over medium clay
Padthaway
Recycled Wastewater irrigation ~1.4 ML/yr
Recycled Wastewater irrigation ~1.2 dS/m (770 ppm)
Mt Gambier
Pilot Study
Pre-trial - Vintage 2013
Soil salinity (Sept 2012)
4
160
140
50yr AVG
2012
3
100
ECe (dS/m)
Rain (mm/month)
120
80
60
40
20
2
1
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
Under-vine
Petiole (Nov 2012)
Cl- < 0.5 %
Na+ < 0.15 %
Mid-row
Pilot Study
A
B
Control (no change)
Mid-row plastic covered mound
Pilot Study
C
Mid-row mound
Pilot Study
D
Mid-row mound sprayed with surface sealing polymer
Pilot Study
E
Buried plastic covered mid-row mound
Pilot Study
Treatments installed in December 2012
A
B
C
Vintage 2013
D
E
< 20 mm rain between treatment construction and vintage 2013
No significant difference in:
• harvest data
• post-harvest soils
• pruning weights
Yield
Sugar
pH
TA
Na
Cl
UV soil
MR soil
Pruning wt
=
=
=
=
=
=
=
=
=
2.2 kg/vine
25.3°Brix
3.5
6.0 g/L
20 mg/L
30 mg/L
3.3 dS/m
0.9 dS/m
1.7 kg/vine
Pilot Study
Vintage 2014
A
B
C
D
E
Yield (kg/vine)
4.8
b
6.1
a
5.2
ab
5.1
ab
5.2
ab
Bunch Wt (g)
43.3
b
51.1
a
45.1
ab
46.8
ab
45.6
ab
Juice TSS (°Brix)
22.9
a
22.2
b
23.0
a
23.0
a
22.6
ab
5.2
b
5.7
a
5.3
Juice TA (g/L)
ab
5.4
ab
5.7
Values followed by same letter are not significantly different (P=0.05)
No difference in:
number of bunches
berry weight
juice pH
113/vine
0.83 g
3.6
a
Pilot Study
Vintage 2014
Leaf petiole at flowering:
A
B
C
D
E
Na+(% dw)
0.33
a
0.22
b
0.28
ab
0.30
ab
0.29
ab
Cl-(% dw)
0.83
a
0.63
b
0.71
ab
0.72
ab
0.71
ab
Values followed by same letter are not significantly different (P=0.05)
Trends emerge at P=0.1
Pilot Study
Vintage 2014
Leaf blade at harvest:
A
B
C
D
E
Na+(% dw)
0.13
ab
0.12
b
0.14
ab
0.16
a
0.13
b
Cl-(% dw)
0.47
a
0.37
b
0.46
a
0.47
a
0.46
a
Values followed by same letter are not significantly different (P=0.05)
Pilot Study
Vintage 2014
Grape juice at harvest:
A
B
C
D
E
Na+(% dw)
28.6
ab
24.6
b
29.3
a
28.6
ab
27.9
ab
Cl-(% dw)
37.0
a
29.5
b
35.4
a
36.5
a
32.1
ab
Values followed by same letter are not significantly different (P=0.05)
Trends emerge at P=0.1
Summary
Proof of concept – Groundwater, Padthaway SA
Rainfall redirection:
reduced under-vine soil salinity by 40%
reduced juice sodium by 25%
reduced juice chloride by 40%
‘Proof of concept’ treatments commercially impractical
Pilot study – Recycled Wastewater, McLaren Vale SA
Early results consistent with ‘Proof of Concept’ trial
(Same response with different climate, soil, management etc.)
Commercially applicable treatments differentiate at P=0.1
Further information from:
www.npsi.gov.au/products/npsi1212
Agricultural Water Management
Vol 129, Nov 2013, p130-137
Further information from:
australianwaterrecycling.com.au
goyder.sa.gov.au
Tim Pitt
SARDI – Water Resources, Viticulture & Irrigated Crops
T. 08 8303 9690 M. 0434 600 504
tim.pitt@sa.gov.au