Reducing water use for frost protection Mark Battany Farm Advisor
Current season will be challenging • Reduced water available for sprinkler frost protection in some areas • Warm winter leading to early bud break may cause extended frost risk season • Competition for scarce water resources will only increase in the future; this isn’t a oneyear problem
Strategy outline • Maximize use of passive protection measures • Wind machines where feasible/available
• Minimize water use when sprinklers are operated • More information: – http://cesanluisobispo.ucanr.edu/Viticulture/Frost_Protection/
Passive measure: Site selection
Photo: Mark Battany © 2014 UC Regents
Passive measure: Air drainage
Photo: Mark Battany © 2014 UC Regents
Passive measure: Vineyard design Temperature before sunrise
Photo: Mark Battany, © 2014 UC Regents
Photo: Mark Battany, © 2014 UC Regents
Passive measure: Variety habit Chardonnay; Frosted
Cabernet Sauvignon; Still dormant
Photo: Rhonda Smith © 2014 UC Regents
Passive frost protection measures • Vineyard floor management is the one thing we can easily change this year • Maximum warming occurs with: • Bare exposed soil, well settled • Moderate moisture content • Dark surface
• These conditions maximize storage of heat during daytime, to be re-radiated at night
Passive measure: Floor management • Large cover crops consume water and increase frost risk
Photo: Mark Battany, © 2014 UC Regents
Passive measure: Floor management • Mowing
Photo: Mark Battany, © 2014 UC Regents
Passive measure: Floor management • Tillage to create bare exposed soil surface
Photo: Mark Battany, © 2014 UC Regents
Inversion strength determines the temperature gain achieved with wind machines
Increasing warming >>>>
Temperature gain with wind machine
Increasing inversion strength >>>>
$250 and some patience
Photo: Mark Battany, © 2014 UC Regents
Photo: Mark Battany, © 2014 UC Regents
Two ways to determine the suitability of wind machines
$30,000+ and some faith
Regional inversion study 35 ft.
5 ft.
Photo: Mark Battany, © 2014 UC Regents
Instructions available
Grower inversion assessment • Example of Gallo sites
Gallo tower sites Josh Rubin Nathan Sparrow Brodie McCarthy
Example data
NOAA-UCCE live reporting towers
Photo: Mark Battany, © 2014 UC Regents
Photo: Mark Battany, © 2014 UC Regents
2014 Central Coast • Combining three projects into single large stations (24) • Rainfall, soil moisture • Temperature inversion • Temperature profile • Other frost sensors • Live data online Photo: Mark Battany, © 2014 UC Regents
Sprinkler frost protection
Photo: Mark Battany, © 2014 UC Regents
Strategies to use less water • Start & stop times ideally based on wet bulb temperature • “Temperature dip” by evaporative cooling occurs at start and at end of operation Conditions resulting in wet bulb of 32 °F Dew point (°F) Air temp (°F)
32
31
30
29
28
27
26
25
24
23
32.0 32.7 33.3 34.0 34.6 35.2 35.7 36.3 36.8 37.3
Strategies to use less water Use appropriate sprinkler heads
http://lawr.ucdavis.edu/ce_frost_protection.htm
Strategies to use less water Use appropriate sprinkler heads
http://lawr.ucdavis.edu/ce_frost_protection.htm
Strategies to use less water • Directional or targeted sprinklers – Advantages • Can use less water per acre, especially at wider row spacings
– Disadvantages • More maintenance needed • Wind can blow water off target • Water savings reduced at narrower row spacings Photo: Mark Battany, © 2014 UC Regents
Wind machines & sprinklers together? • Is it possible to run wind machines initially, and then switch to sprinklers if it gets too cold? • Evaporative cooling upon starting sprinklers will cause temperature to drop below the damage threshold! Wet bulb when air temp is 30 °F RH %
100 90
80
70
60
50
40
30
20
10
Wet bulb (°F)
30
28
27
26
25
24
23
22
21
29
Other protective measures • Delayed pruning – Well suited to small cold areas – Not practical on a large scale; labor • Spray materials – Practicality to apply before frost? – Effectiveness? – Look for supporting independent research
Salinity concerns Mark Battany Farm Advisor
Marginal quality groundwater 4
Data from 56 wells in the Paso Robles area * This problem occurs in other areas too*
3 Well water 2 ECw (dS/m)
Major problems
Increasing problems
1
0
1
3
5
7
9
11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55
Criteria for soil salinity and potential yield reductions Salinity Hazard ECe (dS/m)
Effects on grapevine growth
Non-saline
16
All grapevines will die
Lanyon, Cass and Hansen: “The effect of soil properties on vine performance” CSIRO publication 34/04.
Saline vineyard in Argentina
Photo: Mark Battany, © 2014 UC Regents
Photo: Mark Battany, © 2014 UC Regents
Example: Syrah vines mixed in a block of Cabernet Sauvignon
Photo: Mark Battany, © 2014 UC Regents
Variety response to salinity
Paso Robles salinity survey San Miguel
Shandon Paso Robles
2006-2012 salinity survey samplings
Soil ECe and vine growth
Relationship for a moderately sensitive rootstock
Soil ECe and vine growth
Soil ECe and vine growth
Soil ECe and vine growth
Soil ECe and vine growth
Deep assessment of salt fate • 8 feet deep – vine row, wheel track, row middle • Seven locations: Paso Robles (4) and Santa Barbara County (3)
Photo: Mark Battany, © 2014 UC Regents
ECe
Vine row 0
Soil depth (cm)
30
60 ECe (dS/m) 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
90
120
150
180
210
240
Row middle
pH
Vine row 0
Soil depth (cm)
30
60
pH 5.8 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4
90
120
150
180
210
240
Row middle
Sodium
Vine row 0
Soil depth (cm)
30
60
Na (meq/L) 4 6 9 12 15 18 21 24 27
90
120
150
180
210
240
Row middle
Leaching • Drip irrigation – Not able to flush entire soil profile; limited to smaller soil volume
– Goal is to keep salts away from root zone
Salt movement patterns
Photo: Dean Harrell
Leaching • Sprinkler irrigation – Requires very large amounts of water to fully reclaim soils; 3-4 feet common
Photo: Mark Battany, © 2014 UC Regents
Leaching trials in Australia
2012 publication: “Managing soil salinity in groundwater irrigated vineyards” Robert Stevens, Tim Pitt; SARDI
Salinity management • • • •
Test water & soil to know salinity status Ensure good soil drainage Leaching irrigations when rainfall inadequate Amendments to displace sodium – Gypsum – Sulfur or acid if lime present • Salt-tolerant vine material
• Projects funded by: – American Vineyard Foundation – CDFA Specialty Crops Block Grants – NOAA Earth Systems Resource Lab • UCCE Team: – Mark Battany, Farm Advisor – Gwen Tindula, Staff Research Associate – Rhonda Smith, Farm Advisor – Glenn McGourty, Farm Advisor – Rick Snyder, Biometeorology Specialist
