Vineyard Water Management
Pierre Helwi
Texas A&M AgriLife Extension Service
Grape CampNovember 7, 2016
Lady Bird Johnson Park Pioneer Pavilion, Fredericksburg, TX
Climate
Soil
Human factor
Genetic factor
Wine quality
Seguin 1986; Vaudour 2002; van Leeuwen et al., 2006
Terroir Concept
• Vineyard operations: water management…
• Winemaking
Temperature
Radiation
Precipitation
Climate
Composition and physical structure
Water-holding capacity
Pedoclimate
Nutrients
Soil Human factor
Viticulture practices- Irrigation- Floor management- …
Winemaking
Terroir and Water Management
Variety
Rootstock
Genetic factor
Soil evaporation
Vine transpiration
Vine Water Relations
Melotto et al., 2008
Vine Water Relations
Water
Water vapor move out
Air (CO2) move in
OpenedStomata
Melotto et al., 2008
Stomata open in sunlight for photosynthesis
Vine Water Relations
Water
Melotto et al., 2008
Stomata partially close in response to water stress reduction of
photosynthesis
ABA
ClosedStomata
Reduction in CO2 intake
Irrigation Management
1. When to start irrigation?
2. How much water to apply?
3. Should the irrigation strategy change during
the season?
Photo by Jeff Vanuga, USDA.
When to start irrigation?
Timing of irrigation determined by 3 techniques:
1. Physiological technique Visual symptoms
When to start irrigation?
Photos by Michelle Moyer and Markus Keller, Washington State University
Grayish-green shoot tips Wilted leaves Curled and brown leaves Shriveled berries
When to start irrigation?
2. Vine water status Pressure chamber (pressure bomb)
Stem water potential
Less than -1 MPa No stress
-1 to -1.2 MPa Mild stress
-1.2 to 1.4 MPa Moderate stress
-1.4 to -1.6 MPa High stress
Above -1.6 MPa Severe stress
Prichard et al. 2004Photos from UCCE Sonoma County
3. Soil water statusMoisture sensors
• Different types of sensors
• Critical values vary with sensor type
• Sensors determine if:
o Rainfall reaches root area
o Length of irrigation time
• Proper placement of sensors
When to start irrigation?
Sensors
How much water to apply?
How much water to apply?
Evapotranspiration:
Loss of water from soil evaporation
and vine transpiration
Soil evaporation
Vine transpiration
Evapotranspiration = ET
How much water to apply?
ET0 calculated using:
• Air temperature
• Humidity
• Solar radiation
• Wind speed
Soil evaporation
Grass transpiration
Reference Evapotranspiration = ET0
http://texaset.tamu.edu/
http://texaset.tamu.edu/
Reference Evapotranspiration = ET0
How much water to apply?
Grapevine Evapotranspiration = ETc
How much water to apply?
ETcReference ET0 x Crop Coefficient (Kc) =
Kc increases during late-spring and early summer with canopy vigor
Crop Coefficient (Kc)
How much water to apply?
• For a particular vineyard block• At a specific time
Crop Coefficient (Kc)
How much water to apply?
KcPercentage shaded area
(PSA)x 0.017 =
• For a particular vineyard block• At a specific time
Williams and Ayars 2005
PSA = Average width shaded area / Row width
Photos courtesy of Dr Ed Hellman
Crop Coefficient (Kc)
How much water to apply?
KcPercentage shaded area
(PSA)x 0.017 =
• For a particular vineyard block• At a specific time
PSA = Average width shaded area / Row width
Paso Panel
Crop Coefficient (Kc)
How much water to apply?
KcPercentage shaded area
(PSA)x 0.017 =
• For a particular vineyard block• At a specific time
Williams and Ayars 2005
PSA = Average width shaded area / Row width
Photos courtesy of Dr Ed Hellman
Crop Coefficient (Kc)
How much water to apply?
KcPercentage shaded area(PSA)
x 0.017 =
Average width shaded area / Row width x 100
3 ft/ 10 ft x 100
= PSA
= 30%
Williams and Ayars 2005
Photos courtesy of Dr Ed Hellman
Crop Coefficient (Kc)
How much water to apply?
KcPercentage shaded area(PSA)
x 0.017 =
Williams and Ayars 2005
Kc30% x 0.017 =
Kc0.51 =
Grapevine Evapotranspiration = ETc
How much water to apply?
ETcReference ET0 x Crop Coefficient (Kc) =
0.663 inches1.3 inches x 0.51 =
x 27,152gal/acre-inch
18,001 gal/acre
Grapevine Evapotranspiration = ETc
How much water to apply?
Replacing ALL water used by vine
How much water to apply?
Replacing PORTION of water used by vine
No deficit irrigation Deficit irrigation
Should the irrigation strategy change during the season?
Budbreak to bloom:
• Young bud hydration
• Shoot growth
• Canopy development
• Nutrient uptake from soil
Irrigation and Vine Developmental Stages
No deficit irrigation
Bloom to veraison:
• Canopy growth
• Cluster development
• Next season buds formation
• Cell division and expansion (berry size)
Irrigation and Vine Developmental Stages
Deficit irrigation
Irrigation and Vine Developmental Stages
Veraison to harvest:
• Excess water berry splitting and dilution of quality compounds
• Severe water stress high alcohol and astringency
Water deficit depending on strategy
Irrigation and Vine Developmental Stages
A: Young vineyardB: Vineyard for aromatic whites
and fruity redsC: Vineyard for concentrated reds
Adapted from Ojeda et al. 2014
Irrigation and Vine Developmental Stages
After harvest:
• Reserve for next season
• Signs of acclimation
• Root development
No deficit irrigation
Floor management
Water management by floor management
Cover crops:
• reduction of excessive vine vigor
Vigorous vines Balanced vinesPhotos courtesy of Dr Ed Hellman
Water management by floor management
Cover crops:
• adapted to high rainfall regions
Low rainfallHigh rainfall
Photos courtesy of Dr Ed Hellman
Water management by floor management
Cover crops:
• Several options:
o Type of cover crops
o Cover crop width
o Mowing height and timingCover crop width
Alternate row cultivationMowing height and timing
Ph
oto
s cou
rtesy of D
rEd
Hellm
an
Water management by floor management
Cover crops:
• To be avoided in new planted vineyards
Photos courtesy of Dr Ed Hellman
Grape Irrigation Decision Guide
What time of year is it?
Budbreak to bloom Bloom to veraison Veraison to harvest Harvest to dormant
Sufficient rainfall to replenish 100% of vine water loss?
Yes
No need to irrigation
No
Water to replace full ET
How severe are signs?
Signs of water stress?
SevereMild
Continue with current strategy. Adapt it with
conditionsIncrease irrigation
rates
YesNo
Want to practice deficit irrigation?
Yes No
Continue with current strategy
Slowly reduce irrigation rates
NoYes
Signs of water stress?
Vigorous canopy?
NoYes
Reduce irrigation rates
Slowly reduce irrigation rates
NoYes
Rainfall or sufficient irrigation?
No need to irrigate
Irrigation
Adapted from Washington State University Extension, Irrigation basics for eastern Washington vineyards
Grape Irrigation Decision Guide
What time of year is it?
Budbreak to bloom
Sufficient rainfall to replenish 100% of vine water loss?
Yes
No need to irrigation
No
Water to replace full ET
Adapted from Washington State University Extension, Irrigation basics for eastern Washington vineyards
Grape Irrigation Decision Guide
What time of year is it?
Budbreak to bloom Bloom to veraison
Sufficient rainfall to replenish 100% of vine water loss?
Yes
No need to irrigation
No
Water to replace full ET
How severe are signs?
Signs of water stress?
SevereMild
Continue with current strategy. Adapt it with
conditionsIncrease irrigation
rates
YesNo
Want to practice deficit irrigation?
Yes No
Continue with current strategy
Slowly reduce irrigation rates
Adapted from Washington State University Extension, Irrigation basics for eastern Washington vineyards
Grape Irrigation Decision Guide
What time of year is it?
Budbreak to bloom Bloom to veraison Veraison to harvest
Sufficient rainfall to replenish 100% of vine water loss?
Yes
No need to irrigation
No
Water to replace full ET
How severe are signs?
Signs of water stress?
SevereMild
Continue with current strategy. Adapt it with
conditionsIncrease irrigation
rates
YesNo
Want to practice deficit irrigation?
Yes No
Continue with current strategy
Slowly reduce irrigation rates
NoYes
Signs of water stress?
Vigorous canopy?
NoYes
Reduce irrigation rates
Slowly reduce irrigation rates
Adapted from Washington State University Extension, Irrigation basics for eastern Washington vineyards
Grape Irrigation Decision Guide
What time of year is it?
Budbreak to bloom Bloom to veraison Veraison to harvest Harvest to dormant
Sufficient rainfall to replenish 100% of vine water loss?
Yes
No need to irrigation
No
Water to replace full ET
How severe are signs?
Signs of water stress?
SevereMild
Continue with current strategy. Adapt it with
conditionsIncrease irrigation
rates
YesNo
Want to practice deficit irrigation?
Yes No
Continue with current strategy
Slowly reduce irrigation rates
NoYes
Signs of water stress?
Vigorous canopy?
NoYes
Reduce irrigation rates
Slowly reduce irrigation rates
NoYes
Rainfall or sufficient irrigation?
No need to irrigate
Irrigation
Adapted from Washington State University Extension, Irrigation basics for eastern Washington vineyards
Conclusion
• Irrigation + floor management to manage soil moisture
• Understanding of vine environment
• There are no silver bullets!
• Grapevines are tolerant to water stress
THANK YOUFOR YOUR ATTENTION !
More literatures
• Burt 2012, Wine Grape Irrigation Management
• Hellman, Irrigation Scheduling of Grapevines with Evapotranspiration Data
• Washington State University Extension, Irrigation basics for eastern Washington vineyards
• Peters, Practical use of soil moisture sensors for irrigation scheduling
• Prichard et al. 2004, Deficit irrigation of quality winegrapes using micro-irrigation techniques
• Prichard, Winegrape irrigation scheduling using deficit irrigation techniques
• Westover and Beal 2014, Using Soil Moisture Sensors for Vineyard Irrigation Management