Redirecting rain to manage soil salinity: Lessons from groundwater and recycled wastewater irrigated...
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Transcript of Redirecting rain to manage soil salinity: Lessons from groundwater and recycled wastewater irrigated...
Redirecting rain to manage soil salinity:Lessons from groundwater and recycled wastewater irrigated vineyards
Tim Pitt, Rob Stevens, Jim Cox and Mike McCarthySARDI – Water Resources, Viticulture & Irrigated Crops
4 June 2014
Adelaide
Mt Gambier
Padthaway
McLaren Vale
Salinity and yield response
Proof of concept – Padthaway (Groundwater)Pre-trial investigations
Pilot study – McLaren Vale (Recycled Wastewater)
Summary
HypothesisResults
Progress
Outline
Project Background
1000EC = 1000µS/cm = 1mS/cm
= 1dS/m = 640mg/L = 640ppm
Salinity and Yield Response
0 2 4 6 8 100
20
40
60
80
100
120
ECe (dS/m)
Rela
tive
Yiel
d (%
)
Grape yield decline threshold~2.1 dS/m (1340 ppm)
Salinity and Yield Response
2007 – 2009 salinity project developed for South East SA
Increasing groundwater salinity
Downward trend in rainfall
Introduction of regulated allocations
Emerging salinity damage
2010 – 2012 ‘Proof of concept’ trial
AIM – to identify techniques to manage rootzone salinity in vineyards receiving supplementary saline ‘groundwater’ irrigation
Project Background
Adelaide
Mt Gambier
Padthaway
Padthaway:Wine grape (Chardonnay)
Sandy loam to clay over limestone
Groundwater irrigation ~1.9 ML/yr
Proof of Concept
Groundwater Irrigation ~2.2 dS/m (1400 ppm)
0
2
4
6
8
10
0
2
4
6
8
10
0
4
8
12
16
20
SAR
Salinity higher UV than in MR
Sodicity higher UV than in MR
Salt symptoms in vines, petiole Cl- = 1-1.5 % (toxic)
Mid-rowUnder-vine
Salinity
ECe
(dS/
m)
Sodicity
Salt and sodicity distribution across vineyard floor
Infiltration >30 mm/hr at both points
Pre-trial measures 2009Proof of Concept
Nov-08 May-09 Nov-09 May-10 Nov-10
(mm
)
0
20
40
60
Ave
rag
e r
oo
tzo
ne
EC
e (
dS
/m)
0
2
4
6
8
10
(mm
)EC
e (dS
/m)
Autumn AutumnSpring Spring
Average rootzonesalinity under-vine
RainIrrigation
Yielddecline
threshold
Winter rain flushing salt from rootzone
High SAR under-vine not impeding infiltration
Proof of Concept
Re-distributing rain falling on the mid-row to under the
vine will reduce rootzone salinity
HypothesisProof of Concept
Soil ECPlant Na+ and Cl-
Yield componentsVigour
Proof of Concept
Reduced under-vine soil salinity by 40%
Results
4.1 dS/m 2.5 dS/m
Proof of Concept
Rain re-directed from mid-row to under-vine?
Juice Vintage No Yes Na+ (mg/L)
2010 46 -
2011 33 28 *
2012 28 18 **
Cl- (mg/L)
2010 138 -
2011 72 49 *
2012 59 29 **
* < 0.05 ** < 0.001
Re-directing rain from mid-row to under-vine soils:
• reduced juice Na+ by 25 % and Cl- by 40 %
ResultsProof of Concept
Treatments are NOT commercially viable!!
PROBLEM Will more commercial treatmentsbe as effective?
A
C
B
D E
Proof of concept Pilot study
Adelaide
Mt Gambier
Padthaway
McLaren Vale:Wine grape (Cabernet Sauvignon)
Clay loam over medium clay
Recycled Wastewater irrigation ~1.4 ML/yr
Pilot Study
Recycled Wastewater irrigation ~1.2 dS/m (770 ppm)
McLaren Vale
Cl- < 0.5 % Na+ < 0.15 %
0
1
2
3
4
Mid-rowUnder-vineEC
e (d
S/m
)
Soil salinity (Sept 2012)
Petiole (Nov 2012)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Rai
n (m
m/m
onth
)
0
20
40
60
80
100
120
140
160
50yr AVG 2012
Pre-trial - Vintage 2013Pilot Study
Pilot Study
Control (no change)
AMid-row plastic covered mound
B
Mid-row mound
Pilot Study
C
Mid-row mound sprayed with surface sealing polymer
Pilot Study
D
Buried plastic covered mid-row mound
Pilot Study
E
A CB D E
Treatments installed in December 2012
< 20 mm rain between treatment construction and vintage 2013
Yield = 2.2 kg/vineSugar = 25.3°Brix pH = 3.5TA = 6.0 g/LNa = 20 mg/LCl = 30 mg/LUV soil = 3.3 dS/mMR soil = 0.9 dS/mPruning wt = 1.7 kg/vine
Vintage 2013
No significant difference in:
• post-harvest soils
• pruning weights
• harvest data
Pilot Study
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
Juice TA (g/L) 5.2 b 5.7 a 5.3 ab 5.4 ab 5.7 a
Values followed by same letter are not significantly different (P=0.05)
number of bunches 113/vine
Vintage 2014Pilot Study
No difference in:berry weight 0.83 gjuice pH 3.6
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)
Vintage 2014Pilot Study
Leaf petiole at flowering:
Trends emerge at P=0.1
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)
Vintage 2014Pilot Study
Leaf blade 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)
Vintage 2014Pilot Study
Grape juice at harvest:
Trends emerge at P=0.1
Proof of concept – Groundwater, Padthaway SA
Pilot study – Recycled Wastewater, McLaren Vale SA
Summary
Early results consistent with ‘Proof of Concept’ trial(Same response with different climate, soil, management etc.)
reduced under-vine soil salinity by 40%
‘Proof of concept’ treatments commercially impractical
Rainfall redirection:reduced juice sodium by 25%
reduced juice chloride by 40%
Commercially applicable treatments differentiate at P=0.1
Further information from:
www.npsi.gov.au/products/npsi1212 Agricultural Water ManagementVol 129, Nov 2013, p130-137
australianwaterrecycling.com.au
goyder.sa.gov.au
Tim PittSARDI – Water Resources, Viticulture & Irrigated Crops
T. 08 8303 9690 M. 0434 600 [email protected]
Further information from: