Effect of Soil Water Tension Threshold for Irrigation on Cranberry Yield, Yield Components and Water...
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Transcript of Effect of Soil Water Tension Threshold for Irrigation on Cranberry Yield, Yield Components and Water...
Effect of Soil Water Tension Threshold for Irrigation on Cranberry Yield, Yield
Components and Water Productivity
AUGUST 27TH 2013NACREW QUÉBEC
Vincent [email protected]
Jacques GallichandJean Caron
Water Table
40 cm
10 cm
4 kPa
h = 40 cmSWT = 4 kPaφm = -4 kPa
SOIL WATER TENSION (OR SOIL WATER
POTENTIAL)
This study was conducted to determine the optimum soil water tension for starting
irrigation that would optimize water productivity without decreasing yield and yield
components
(Water productivity was calculated as the yield per unit depth of rainfall and irrigation)
OBJECTIVE
0 2 4 6 8 10 12 14 16 18 20 22 24 260%
10%
20%
30%
40%
50%
Tension (kPa)
Soi
l Wat
er C
onte
nt
WET (5.5 kPa)
DRY (7.0 – 10.0 kPa)
CONTROL (6.0 - 6.5 kPa)
IRRIGATION THRESHOLDS
RETENTION CURVE
MEASUREMENTS• Soil water tension (Tensiometer)
• Rainfall (Weather Station)
• Irrigation water (Flow meter)
• Yield : 2474 samples (929 cm2)
• Yield components : 132 samples (929 cm2)
• Water Productivity (Yield / (Rainfall+Irrigation))
Statistical analysis to determine the best threshold
YIELD
In 2011 No difference between treatment
In 2012 No difference between 5.5 to 8.5 kPa
Significant reduction of 11 % in the driest treatment (10.0 kPa)
Average yield: 33690 lbs/acre
YIELD COMPONENTS
In 2011 : No significant difference
In 2012 - Significant differences :
- 21 % of marketable berries at 10.0 kPa
- 14 % of berries / upright at 8.5 kPa - 9 % less fruit set at 8.5 kPa
- 7 % of berry weight at 8.0 kPa
No difference between 5.5 and <8.0 kPa
WATER PRODUCTIVITY
2011-2012 : Significantly greater in Dry treatments
Wet (5.5 kPa) : 54 – 186 % more irrigation water
Dry (7.0–10.0 kPa) : 21 – 93 % less irrigation water
0 2 4 6 8 10 120
25
50
75
100
125
150
175
DryingWetting
Tension (kPa)
K (m
m/h
)HYDRAULIC CONDUCTIVITY VS SOIL WATER
TENSIONWater stress
affected yields and yield
components
Good capillary riseOptimum yieldsWater savingsEnergy savings
7 8 9 100
1
2
3
4
5
Maximum ET rate
CONCLUSION
In fine sand, Dry treatments, with irrigation thresholds ranging from 7.0 to 7.5 kPa, improved significantly the water productivity without decreasing yield and yield components
CURRENT RESEARCH(2013-2015) The capillary rise is sufficient to meet the plant
needs when the water table is controlled at an optimal level