Deficit Irrigation Scheduling for Quality Winegrapes

Transcription

1 Deficit Irrigation Scheduling for Quality Winegrapes Terry Prichard, Water Management Specialist Dept. LAWR, Hydrology UC Davis Improving Fruit Quality

2 Improving Fruit Quality Crop Crop Load Management Pruning/Thinning Canopy Canopy Management Trellis/Leaf Removal Crop Crop Selection (drop) Ripeness Ripeness Harvesting Water Water Deficits Timing and Severity

3 Deficit Irrigation Vegetative growth - Improved color + Improved characteristics + Yield - / 0 Water volume/costs +

4 Water Use Climate Evapotranspiration Reference (ETo( ETo) Sun Interception Size of Canopy (Kc( Kc) Time of season (canopy expansion) Spacing Trellis

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6 CIMIS California Irrigation Management Information System Evapotranspiration Reference (ETo( ETo) ) Rainfall

7 Relationship Between Percent Land Surface Shaded and Vineyard Kc 1.5 Y = 0.017X Kc Percent Shaded Area at Midday LE Williams 44 x = 0.75 Kc

8 May 10 7:30 Quad Vertical

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11 Balance Vegetative/Reproductive Structure

12 Vineyard Development SelectionSelection Soil/Climate Resources Rootstock Clone Spacing Trellis type

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14 Irrigation Management Philosophy Controlled water deficits can improve fruit quality with little effect on yield

15 Moderate Water Deficits Reduce Reduce vegetative growth Shoot length No. of lateral shoots Increase diffused light to fruit

16 Relative Rate vs. Leaf Water Potential Net Photosynthesis Percentag e Expansive Growth Midday Leaf Water Potential (-bars)

17 Quality Goals Titratable acidity Tartaric/Malic ratio ph Potassium Extractable PhenolicsPhenolics Extractable TanninsTannins

18 Cabernet Sauvignon, 2000 Location Tons per acre Yield: Prun wt Soluble solids ( o Brix) Titratable acidity (g/l) ph Anthocyanins (mg g - 1 FW) Parlier ~ Lodi ~ Oakville ~

19 Cabernet Deficit Irrigation % of ETc Variable % of 100% Treatment Berry Size

20 Lodi Merlot Yield 20 (lbs/vine) Treatments

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23 Shoot, Root, and Berry Growth Rate Flowering Veraison Harvest Days from budbreak 0 Shoot Elongation Rate (cm/day) Berry Grow th R ate (g/day/100 berries) Shoots Roots Berries Mullins, 1992

24 Shoot Growth, Merlot, Lodi, 1999 T1 T3 T7 T8 T9 T10 7/15 5/20 5/27 6/3 6/10 6/17 6/24 7/1 7/8 5/13 5/6 Leng th ( cm )

25 Irrigation of Quality Winegrapes Determine When How much Achieve Achieve a predictable response

26 Developing a Strategy To Accomplish the Set Goal Fruit quality/yield When When to Begin Irrigation How How much to Apply

27 When to Begin Irrigation Shoot Shoot Growth Tip Tip Rating Mid Mid day Leaf Water Potential Soil Soil Based Monitoring Decision

28 Soil Moisture Measurement Quantitative (quantity) Qualitative (status)

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32 Quantitative Moisture Measurement Methods Gravimetric / Volumetric Soil Sampling Neutron Moisture Meter Dielectric Moisture Sensors Capacitance Probes Frequency Domain Reflectometry (FDR)

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37 Pressure Chamber

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40 Diurnal Leaf Water Potential 0 Time Bars 4 6 8

41 Leaf Water Potential, Lodi Merlot 6/11/ Bars Time of Day 12 = Noon

42 Pressure Bomb When to sample (solar noon hr.) No. of vines/block (6 average vines) No. of leaves (2/vine) Leaf selection (young/fully expanded) Leaf bagging (before excising) Rate of pressure increase (3 sec/bar) Leaf care (breaking veins)

43 Deficit Threshold + RDI Begin Begin irrigation at a specific leaf water potential threshold After After threshold, irrigate at fraction of full water use

44 When to Begin Irrigation Deficit threshold method leaf water potential threshold -10 to -14 bars

45 Leaf Water Potential Selecting a Threshold Enough to Stop Vegetative Growth Variety, Wine Goal, Region

46 How Much Water Deficit threshold method After threshold, a fraction of full vine water use Full vine water use x RDI % Rdi % %

47 How Much Water to Apply Volume Volume of water to apply Gallons per vine per week Not Not restart vegetative growth Continue Continue Sugar accumulation (Photosynthesis) Protect Protect fruit (cover)

48 Midday Leaf Water Potential 2000 Cabernet, Hopland 5/20 6/3 6/17 7/1 7/15 7/29 8/12 8/26 9/9 9/23 10/7 10/ Bars Begin irrigation T Begin irrigation T4, T5, T6 Switch T6 to 60% T1 100% T4 12/60 T5 12/35 T6/12/35-60

49 Determining the Irrigation Volume ETo X Kc = Full Potential Vine Water Use (Etc) ETc X RDI% = Net Water Volume Needed Net Irrigation X Emission Uniformity = Gross Irrigation Volume

50 Eto and precipitation from 2002 Assumes that Leaf Water Potential Threshold was reached June 16 HARVEST DATE: Septmember 15 Madera 2002 A = C = Potential B = A x B: Water D = E = F = G= [(C x D) - E - F] H = Crop Potential Use Thru RDI Soil Effective Emmision Gross Vine Date ETO Coeficient Water Use Harvest Coeficient Contrib. Rainfall Net Irrigation Uniform ity Irrigation Spacing Period Inches/ Kc (in) (in) Krdi (in) (in) (in) (%) (in) (sq feet) Period Jun Jul 1-15 Jul Aug 1-15 Aug Sept 1-15 Sept Oct Oct I = G/H: J = (I x J x 0.623) Gallons per Vine / Period Total Gallons per vine applied through harvest =

51 Stn Id Station Date Jul CIMIS ETo (in) Precip (in) Biweekly Eto Ppt 145 Madera 6/16/ Madera 6/17/ Madera 6/18/ Madera 6/19/ Madera 6/20/ Madera 6/21/ Madera 6/22/ Madera 6/23/ Madera 6/24/ Madera 6/25/ Madera 6/26/ Madera 6/27/ Madera 6/28/ Madera 6/29/ Madera 6/30/

52 C = Potential A = B = A x B: Water Period ETO Crop Coeficient Potential Water Use Us e Thru Harvest Inches/ Kc (in) (in) Period Jun Jul Jul Aug Aug Sept Sept Oct Oct Total

53 C = Potential A x B: Water D = E = F = Potential Us e Thru RDI Soil Effective Time Water Use Harvest Coeficient Contrib. Rainfall Period (in) (in) Krdi (in) (in) (in) G = [(C x D) - E - F] Net Irrigation Jun Jul Jul Aug Aug Sept Sept Oct Oct Total

54 Madera Station 145 G = (C x D) - E - F] H = I = G / H: J = (I x J x 0.623) Time Net Irrigation Emmision Uniform ity Gross Irrigation Vine Spacing Gallons per Vine / Period Period (in) (%) (in) (sq feet) Jun Jul Jul Aug Aug Sept Sept Oct Oct Total Gallons per vine applied through harvest = 333

55 Madera Station 145 Eto and precipitation from 2002 Assumes that Leaf Water Potential Threshold was reached June 16 HARVEST DATE: Septmember 15 C = Potential G = [(C I = A = B = A x B: Water D = E = F = x D) - E - F] H = G/H: J = (I x J x 0.623) Time ETO Crop Coeficient Potential Water Use Use Thru Harvest RDI Coeficient Soil Contrib. Effective Rainfall Net Irrigation Emmision Uniform ity Gross Irrigation Vine Spacing Gallons per Vine / Period Period Inches/ Kc (in) (in) Krdi (in) (in) (in) (%) (in) (sq feet) Period Mar Mar Apr Apr May May Jun Jun Jul Jul Aug Aug Sept Sept Oct Oct Total Gallons per vine applied through harvest = 333

56 Monitor Effects of Strategy Leaf Leaf Water Potential Vegetative Growth YieldYield QualityQuality Winemaker Comments

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60 Vine Water Use vs. Soil Water Reservoir

61 Vine Water Use vs. Soil Water Irrigation Reservoir

62 Irrigation of Quality Winegrapes Using Micro-Irrigation Techniques Terry Prichard, Irrigation and Water Management Specialist Blaine Hanson, Irrigation and Drainage Specialist Larry Schwankl, Irrigation Specialist Paul Verdegaal, Viticulture Farm Advisor Rhonda Smith, Viticulture Farm Advisor University of California Cooperative Extension Department of Land, Air and Water Resources University of California Davis Supported in part by: Lodi-Woodbridge Wine Commission

63 Irrigation of Quality Winegrapes Using Micro-Irrigation Techniques alternative professional page

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