Almond sensitivity to salt stress
at different growth stages
Tim Pitt, Rob Stevens and Jim Cox
SARDI – Water Resources, Viticulture & Irrigated Crops
30 October 2014
Why study salinity?
Nth. Ad. Plains RW
~1.8 dS/m
Relative growth rate (%)
120
100
Almond vigour decline threshold
80
~1.5 dS/m (960 ppm)
Groundwater
0.8 ­ >2 dS/m
60
40
Murray River
0.2 ­ >1 dS/m
20
0
0
2
4
6
8
Soil Salinity ­ ECe (dS/m)
10
Adelaide tap
0.3 ­ 0.8 dS/m
Trial site
Mature non­pareil almond (15 yrs)
Well drained clay loam over red clay
~9 ML/yr (via Eindor 861’s)
Access to both:
Recycled water
Groundwater
>1.8 dS/m
~1.2 dS/m
Pre-trial investigations
Average rootzone ECe (dS/m)
8
6
Following
extended
drought
Salts rapidly
return
4
Drought breaks
Summer rains
follow wet
winter
2
Vigour decline
threshold
Irrig. and rain (mm)
0
60
Irrigation
Rain
Return to average
rainfall
40
20
0
2010
2011
2012
2013
2014
Pre-trial investigations
JAN 2013
Toxic
Leaf Na+ (% dw)
0.41
>0.25
Leaf Cl- (% dw)
2.06
>0.3
Research question
Timing of drought stress affects Almond yield (Goldhamer, UC Davis)
Timing of salt stress affects Grape yield/quality (Stevens, SARDI)
Timing of salt stress on Almond less well understood…
Can we determine the salt sensitivity of phenologically different
almond growth stages?
Research approach:
Non­saline water imported into a saline growing
system at three different growth stages
Saline water
>1.8 dS/m
Non­saline water
<0.8 dS/m
Growth Stage
TRT
1
2
3
Budburst to
pit hardening
Pit hardening
to harvest
Harvest to
leaf drop
Control
Saline
BB-PH
Non­saline
PH-H
Saline
H-LD
Demo*
* Single demonstration plot only
Saline
Non­saline
Saline
Saline
Non­saline
Non­saline
Treatments installed winter 2013
Irrigation volume & quality
Soil moisture and salinity
Leaf tissue analysis
Plant water relations
Yield & crack­out
Vigour
Year 1 – Snapshot of results
Plant water relations
Less saline treatments trending to
have least negative response to high
evaporative demands
Yield components
No difference in YR1
(yield slow to respond but also slow to recover)
Leaf tissue analysis
Rapid response in leaf sodium and
chloride concentrations
Year 1 – Snapshot of results
Example of plant tissue response:
Leaf chloride (Cl­) normalised for volume weighted salt load (ECVW)
Treatment
ECVW
(dS/m)
Change in leaf Cl­ (%)
End of year
per 0.1 dS/m
Leaf Cl­ (%)
drop in ECVW
Saline water at all stages
1.40
2.26
Fresh water, Budburst – Pit Hardening
1.26
1.78
­0.35
Fresh water, Pit Hardening – Harvest
0.87
0.93
­0.25
Fresh water, Harvest – Leaf Drop
1.22
1.87
­0.21
Fresh water at all stages*
0.55
0.79
­0.17
* One
demonstration plot only
Relevance for industry?
?
NAP growers:
When to make use of different water sources
MDB growers / river managers:
When to avoid flood induced salt spikes
http://paulhumphriesriverecology
International growers:
Water scarcity and salinity not unique to Aus.
http://thealmonddoctor.com
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