1. Effective Water Management: New Tools, Strategies, and Practices
Mark Greenspan, Ph.D., CPAg, CCA
President and Viticulturist
Advanced Viticulture, Inc.
Windsor, CA

2. Topic of Discussion Application of “classic” monitoring tools
Supply and demand monitoring
Leaf Porometer: Demand monitoring
Soil Moisture Profile Monitoring – Supply and scheduling

3. Evaporative Demand / Transpiration
Stomatal Resistance
Hydraulic Resistance
Soil moisture content / matric potential

4. Demand
Supply

5. Demand Supply Transpiration Evaporative Demand, VPD
Stomatal Conductance
Sap Flow - Xylem
Water potential gradients
Supply
Soil Water Content
Rainfall, irrigation, withdrawal
Soil Water Potential
Matric potential, primarily
Rootstock and soil characteristics

6. Demand: Plant Water Status Measurement
Porometer
Pressure Chamber
Other instruments
Sap Flow
Dendrometry
Canopy Temperature / Infrared Thermometry / Remote Sensing
Microtensiometers

7. Suzy Y. Rogiers*, Dennis H. Greer, Ron J. Hutton and Joe J. Landsberg
Journal of Experimental Botany, Vol. 60, No. 13, pp. 3751–3763, 2009

8. Pressure Chamber/Leaf Water Potential (-bars)9 10 11 12 13 14 15 16 17 18 8
“Luxury”
Mid-Range
Mod. Stress
Stress
Extreme Stress
Slight Stress
Shoot stopping
450
400
350
300
250
200
150
100 50
500
“Luxury”
Mid-Range
Mod. Stress
Stress
Extreme Stress
Slight Stress
High WUE Range
Red target
White target
Porometer/Stomatal Conductance - Units are in mmol/m2/s

9. Slow down canopy growth
Vine Water Stress
Maintain canopy
“Magic Window”
Slow down canopy growth
No stress here
Budbreak
Bloom & Fruit Set
Veraison
Maturity

10. Irrigation Scheduling Soil moisture based
Uses soil-moisture sensors to determine depth of irrigation and depletion of soil moisture to determine intervals.
Can be used with or without ET, but it does not require ET assessment
Soil moisture is NOT a SECONDARY measurement to vine water status!!

11. Electronic Soil Moisture measurement
 Soil matric potential sensors
Soil water content sensors & probes 

12. Comparison of soil moisture sensor types
Advantages
Disadvantages
Water content
Available in multi-level probes
Can look at profile at individual depths OR conglomerated
Very difficult to calibrate
Therefore, not a physical measurement
Matric Potential
True physical measurement
Does not require calibration
Discrete sensors not available in multi-level
Measures only the wetter portion of SM
Cannot look at profile as a whole – individual depths only

13. Permittivity of water is about 80x that of air
Permittivity is akin to dielectric constant, which influences capacitance

14. Water Content
Time

16. Actual Irrigation: 12 gallons/vine  18% of ETc
ETo = 4.42”
Kc = 0.5
ETc = 2.21”
= 66 gal/vine
Actual Irrigation: 12 gallons/vine
 18% of ETc
Cab. Sauv, 8’ x 6’ spacing, south Napa County, 3rd leaf

17. Depletion of Ran-fed moisture
24”
32”
40”
16”
48”
May May May 24 Jun Jun 12

18. RECAP
Soil moisture
Track moisture depletions at various depths in the profile
Use to determine depth of irrigation percolation
Use to determine rate of withdrawl to determine irrigation interval
Plant water status
Monitor water stress to achieve desired stress level at desired time

19. Advanced Viticulture, Inc.
Mark Greenspan, Ph.D., CPAg, CCA
Advanced Viticulture, Inc.
Windsor, California
Web: