Effect of Soil Water Tension Threshold for Irrigation on Cranberry Yield, Yield

Components and Water Productivity

AUGUST 27TH 2013NACREW QUÉBEC

Vincent Pelletiervincent.pelletier.8@ulaval.ca

Jacques GallichandJean Caron

1. INTRODUCTION

Water Table

40 cm

10 cm

4 kPa

h = 40 cmSWT = 4 kPaφm = -4 kPa

SOIL WATER TENSION (OR SOIL WATER

POTENTIAL)

YIELD VS SOIL WATER TENSION

2. OBJECTIVE

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

3.

METHODOLOGY

• 3 sites in Québec• 1 site in Wisconsin

EXPERIMENTAL SETUP

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

4. RESULTS

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

5. CONCLUSION

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

Canneberges BielerNature Canneberge

Transport Gaston NadeauSalzwedel Cranberry

Ferme Onésime Pouliot

THANK YOU !!!