Williams, Larry : Vineyard irrigation management

Irrigation strategies to maintain watershed health and vineyard sustainability Larry E . Williams Dept . Viticulture and Enology Univ . California â?? Davis and Kearney Ag Center 9240 S . Riverbend Ave . Parlier , CA Wineâ??s Mammoth Water Footprint : 120 Liters to Make One Glass ! ( 960 L of H O / L of wine ) 2 From article appearing in the Econo mist ( 2009 ) Irrigation management and Vineyard Sustainability â?¢ Maintain productivity over time â?¢ Maximize fruit quality â?¢ Increase vineyard water use efficiency â?¢ Minimize / maximize soil water depletion ( function of soil type and rooting depth , cover crop management ) â?¢ Some of the above factors will be a function of location in California and price of grapes Irrigation management and Vineyard Sustainability â?¢ Install water meters either at the pump or down individual rows ( know how much youâ??ve applied throughout the season and total amount ) â?¢ Make sure drip irrigation system maintained â?¢ Know what ET of your vineyard ( s ) might be â?¢ Use a means to assess vineyard soil water or vine water status ( most methods to monitor vine and soil water status are highly correlated with one another ) Historic monthly rainfall ( inches ) at four locations in California . - - - - - - - - - - - - - - - - - - - - - Location - - - - - - - - - - - - - - - - - - - - - Sonoma : 1893 â?? 2007 Month Sonoma Oakville Fresno Paso Oakville : 1906 â?? 1981 Fresno : 1948 â?? 2007 Jan . 6.26 8.57 2.13 3.48 Paso Robles : Feb . 5.23 5.45 1.89 3.06 1894 - 2007 Mar . 4.18 4.27 1.93 2.49 Apr . 1.82 1.73 1.03 1.01 May 0.80 0.46 0.37 0.36 Jun . 0.23 0.19 0.14 0.06 Jul . 0.03 0.06 0.01 0.02 Aug . 0.09 0.07 0.01 0.06 Sept . 0.34 0.38 0.16 0.18 Oct . 1.63 1.70 0.51 0.59 Nov . 3.94 3.77 1.13 1.38 Dec . 5.22 5.83 1.59 2.54 Total 29.8 32.5 10.9 15.2 What information is needed to determine when to start irrigating ? How does seasonal water use vary as a function of phenology ? Water use of Thompson Seedless grapevines grown in a th weighing lysimeter from March 15 until the ~ date of bloom and veraison and the harvest date and the end of the season ( Oct . 31 ) . One inch = 25.4 mm . Date of ET to Date of ET to Date of ET to ET all c c c c Bloom Bloom Veraison Veraison Harvest Harvest Season Year ( mm ) ( mm ) ( mm ) ( mm ) 1991 5 / 25 99 7 / 8 354 9 / 22 743 866 1992 5 / 5 78 6 / 22 298 9 / 4 704 811 1993 5 / 9 81 7 / 2 321 9 / 21 803 857 - - - - - - - - - - - ET as a percent of season long ET - - - - - - - - - - c c 1991 11.5 41 86 100 1992 9.6 37 87 100 1993 9.5 37 94 100 ET ranged from 32 to 34 inches across years c Water use of Merlot grapevines grown in Madera County th from March 15 until the ~ date of bloom and veraison and the harvest date and the end of the season ( Oct . 31 ) . One inch = 25.4 mm . Date of ET to Date of ET to Date of ET to ET all c c c c Bloom Bloom Veraison Veraison Harvest Harvest Season Year ( mm ) ( mm ) ( mm ) ( mm ) 2001 5 / 16 81 7 / 28 397 9 / 4 579 729 2002 5 / 16 51 7 / 26 389 9 / 10 576 708 2003 5 / 22 79 7 / 24 382 9 / 19 - 27 620 713 2004 5 / 20 98 7 / 15 394 8 / 25 - 9 / 7 616 760 2005 5 / 24 55 7 / 19 300 9 / 16 554 663 - - - - - - - - ET as a percent of Seasonal Estimated ET - - - - - - c c 10 % 52 % 82 % 715 715 mm = 28.1 inches What is available to a grower for assisting in vineyard irrigation management ? â?? We have devices in the vineyards that tell us the exact soil moisture , so we only water when we need to . â?쳌 â?? While traditional methods such as soil tensiometers , pressure chambers and neutron probes are some the best tools available , they only provide part of the picture and do not accurately reflect how a vine is doing . The scatter plot for neutron probe information can be very wide , and what does that really tell you about the vine . â?쳌 â?? Vine water status is valuable information , but leaf water potential can sometimes be misleading . â?쳌 ( California Sustainable Winegrowing Alliance ) What information is needed to determine when to start irrigating ? â?¢ An estimate of the amount of water available in the soil profile ( this can be determined with a neutron probe , capacitance sensors , tensiometers , etc . ) or knowledge of soil type â?¢ Rooting depth of the vines in your vineyard ( a good estimate is ~ 1.2 to 1.5 m ( 4 to 5 feet ) but water extraction may take place at greater depths . â?¢ An irrigation event would take place once a pre - determined value of soil water was depleted . A Illustration of Soil Moisture Terms Field Capacity B Available Readily Available Water Soil Moisture Permanent Wilting Point Completely Dry A At soil saturation the beaker would be full or overflowing . B Readily available water is considered to be ~ 50 % of the available soil moisture . Access tubes Data from lysimeter SWC was measured with a neutron probe to a depth of ~ 1.5 m . The access tubes were directly beneath the drip line . In 1991 , the 0.2 and 0.6 treatments used 132 and 97 mm of water , respectively from the soil profile . ( 5.2 and 3.8 inches ) . Other years the 0.2 treatment used from 3.8 to 7.5 inches . The greatest amount of water depleted in this soil type , sandy loam , with no irrigation was ~ 8 inches . What information is needed to determine when to start irrigating ? â?¢ If you donâ??t monitor soil moisture then measuring midday leaf water potential can be used to determine if the vines are transpiring at full ET c â?¢ Be sure that the proper techniques are used to measure leaf water potential ( find out if you donâ??t know ) â?¢ An irrigation event would take place at a pre - determined value â?¢ I have used values from - 1.0 to - 1.1 MPa ( - 10 to - 11 bars ) in my studies . Some may wait until a value of - 1.2 to - 1.4 MPa is reached . Data from lysimeter Midday demand Data from lysimeter evaporative / ET Grapevine ( 42 % less ) Midday = - 0.75 MPa l Midday = - 1.29 MPa l Many commercially available sap flow sensors will not reliably measure transpiration . Midday leaf water potential close to the initiation of the irrigation treatments in the Merlot vineyard near Madera , CA . Date of Irrigation treatment st Year 1 Irrigation 0.4 0.8 1.2 - - - - - - - - - - - - - ( MPa ) - - - - - - - - - - - - - 2001 May 16 - 1.03 - 1.03 - 1.03 2002 May 30 - 1.16 - 0.99 - 0.93 2003 May 22 - 1.18 - 1.08 - 1.04 2004 May 27 - 1.04 - 0.96 - 0.89 2005 June 10 - 1.06 - 1.00 - 0.94 st Rainfall , reference ET and date of 1 irrigation of Cabernet Sauvignon grapevines grown at Oakville . st Inclusive Rainfall Reference 1 Irrig . Year Dates ( in . ) ET ( in . ) ( date ) 1998 BB â?? 9 / 20 3.70 31.6 7 / 17 1999 BB â?? 9 / 27 0 34.3 5 / 30 2000 BB â?? 9 / 21 3.34 34.4 6 / 5 Reference ET and estimated ET from 2002 to c 2006 for a study at J . Lohr Winery . ET Est . ET Date of % of Seasonal o c st st Year ( mm ) ( mm ) 1 Irr . ET to 1 Irr . c 2002 1075 352 Jun 24 19 % 2003 1212 406 May 4 13 % 2004 1204 511 Apr 11 1 % 2005 1071 558 Jun 19 35 % 2006 1065 475 July 3 36 % Mean 1138 460 ( 44.5 in ) ( 18.1 in ) The first two years of the study the seasonal K for a VSP trellis on 10 ft c rows was used . Subsequently the K was adjusted seasonally for a c larger canopy . Rainfall ( inches ) at Paso Robles from 1997 - 2008 . Nov - Mar Apr â?? Sept October Total Year 1997 9.7 0 0 9.7 1998 18.1 3.4 0.3 21.8 1999 5.0 1.2 0 6.2 2000 9.0 1.5 1.0 11.5 2001 13.0 0.7 0.1 13.8 2002 5.9 0.2 0 6.1 2003 7.7 2.7 0.3 10.7 2004 8.4 0 3.9 12.3 2005 15.0 1.5 0 16.5 2006 9.3 3.1 0.6 13.0 2007 3.5 0.4 0.6 4.5 2008 5.3 - - - - - - - - - Factors affecting vineyard water use ( per land area ) . â?¢ Evaporative demand ( ET ) o â?¢ Seasonal growth of the vine â?¢ Ultimate canopy size ( trellis type ) â?¢ Spacing between rows â?¢ Amount of water in the soil profile â?¢ Presence of a cover crop The following equation can be used to calculate vine water requirements : ET = ET x K c o c where ET = vineyard evapotranspiration , c ET = reference evapotranspiration and K o c = crop coefficient . The above equation will give water requirements in inches or mm ( one acre inch = ~ 27,500 gallons per acre ) ( one mm covering one hectare = 10,000 L ) ET = ET x K c o c In the above equation , â?? The K value c relates to ET of a disease - free , crop grown in large fields under optimum soil water and fertility conditions and achieving full production potential under the given growing environment â?쳌 Doorenbos and Pruitt , 1977 Reliable crop coefficients should take the following into account : â?¢ Seasonal growth of the grapevines â?¢ Final canopy size , which is a function of trellis design â?¢ Row spacing ( the closer the row spacing the greater the water use per acre ) ( 80 % ) ( 59 % ) ( 95 % ) ( 84 % ) Row spacing was 12 ft . How does trellis / training system and row spacing affect estimated vineyard ET ? â?¢ Grapevine water use was estimated using weather data from the Lodi West CIMIS station . â?¢ The two canopy types were a CA sprawl and vertically shoot positioned ( VSP ) trellis . â?¢ The row spacings were 10 and 12 feet for the CA sprawl and 6 and 10 feet for the VSP . â?¢ The seasonal crop coefficients used were those for a CA sprawl and VSP at the designated row spacings . What are the relationships between ET or applied water amounts and c productivity ( water use efficiency ) ? What is the water footprint ? ( 960 L H O / L wine ) 2 I will give several examples of studies I have conducted around the state regarding the above . Regulated Deficit Irrigation ( RDI ) â?¢ The practice of purposely creating water deficits during specific times of the season primarily to save water while minimizing or eliminating negative impacts on yield or crop revenue â?? David Goldhamer Sustained Deficit Irrigation ( SDI ) â?¢ The practice of purposely deficit irrigating beginning with the first irrigation of the season and irrigating such throughout the remainder of the growing season . SDI is based upon knowing what full ET for the vineyard is and then irrigating at a particular fraction of full ET â?? Larry E . Williams Partial Rootzone Drying ( PRD ) â?¢ An irrigation regime whereby vines are watered on one side of the vine ( receiving 50 % , the water of the control treatment ( full ET ) ) during a two week period and then irrigating the next two weeks on the other side of the vine . During the two week period roots on the other side of the vine would experience water deficits â?? Brian Loveys Water balance in a Carneros Chardonnay vineyard from 1999 . Vine and row spacings were 5 and 7 ft . , respectively . Irrigation Treatment ( fraction of ET ) c 0.0 0.5 1.0 - - - - - - - - - - - - - - - - ( inches ) - - - - - - - - - - - - - - - - Soil water depletion 9.8 * 7.8 6.1 Applied water - - - - 5.8 11.6 Total H O 9.8 13.6 17.7 2 * 9.8 inches is equivalent to 213 gallons per vine . Midday leaf water potential of Chardonnay vines on 9 / 21 / 99 And 9 / 12 / 2000 as a function of irrigation treatment and rootstock . Irrigation Treatment ( fraction of ET ) c 0.0 0.5 1.0 1999 - - - - - - - - - - - - - - - - ( MPa ) - - - - - - - - - - - - - - - - 5C - 1.54 - 1.06 - 0.92 110R - 1.81 - 0.98 - 0.86 Mean - 1.68 - 1.04 - 0.89 2000 Mean - 1.43 - 1.11 - 0.86 Water use ( ET ) per ton of fruit or gallons of must of Chardonnay c grown in Carneros . Data are from 1999 ( 1250 vines per acre ) . Irrigation Treatment ( fraction of ET ) c Parameter 0.0 0.5 1.0 4.88 6.26 6.59 Yield ( tons / acre ) 9.8 13.6 17.7 ET ( in . ) c 54,341 58,670 72,357 Gal . H O / Ton fruit 2 453 489 603 Gal . H O / Gal . 2 must ( Water footprint ) 120 gallons of must per ton Applied water per ton of fruit or gallons of must of Chardonnay grown in Carneros . Data are from 1999 ( 1250 vines / acre ) . Irrigation Treatment ( fraction of ET ) c 0.0 0.5 1.0 4.88 6.26 6.59 Yield ( tons / acre ) - - 5.8 11.6 Applied H O ( in . ) 2 - - 25,059 47,608 Gal . H O / Ton fruit 2 - - 208 397 Gal . H O / Gal . 2 must ( Water footprint ) 120 gallons of must per ton The effect of irrigation amount , cultivar and year on productivity of grapevines grown in Napa County . ( both used VSP trellis , Chardonnay was on 2.13 m row and Cabernet Sauvignon on 1.83 m row , vines irrigated 1 - 2 times per week ) Location / - - - - - - - - - - - - - - Irrigation Treatment ( fraction of estimated ET ) - - - - - - - - c Year 0.0 0.25 0.5 0.75 1.0 1.5 Carneros - - - - - - - - - - - - - - - - Yield ( % of maximum or t / acre ) - - - - - - - - - - - - 1998 88 % - - - 95 % - - - 7.88 - - - 1999 74 % - - - 95 % - - - 6.59 - - - 2000 49 % - - - 84 % - - - 8.10 - - - 2001 49 % - - - 83 % - - - 7.30 - - - Oakville 1998 62 % 76 % 99 % 93 % 89 % 6.41 1999 70 % 86 % 99 % 100 % 119 % 4.32 2000 74 % 73 % 93 % 116 % 94 % 6.01 2001 50 % 85 % 114 % 110 % 108 % 5.08 Madera irrigation and canopy management study : specifics â?¢ Three irrigation amounts : 0.4 , 0.8 and 1.2 times estimated ET . c â?¢ Three canopy treatments ( leaf removal in the fruiting zone at berry set or veraison or no leaf removal ) . â?¢ Vine and row spacing was 7 x 12 ft . â?¢ Vines were trained to a bilateral cordon at a height of 48 inches . â?¢ There was no crossarm ( CA sprawl ) . â?¢ The first irrigation of the season did not take place until a midday leaf water potential of â?? 1.0 MPa was measured ET , ET , rainfall and applied water amounts in o c a Merlot vineyard in Madera County . Irrigation Treatment Est . Rainfall ( mm ) Year ET ET Before After 0.4 0.8 1.2 o c App . H O ( % of ET ) - - ( mm ) - - 15 March 2 c 2001 1261 729 33 64 92 137 ( 5.4 in ) 40 ( 1.6 in ) 2002 1257 708 34 65 92 174 ( 6.9 in ) 42 ( 1.6 in ) 2003 1241 714 31 63 94 183 ( 7.2 in ) 42 ( 1.6 in ) 2004 1289 760 36 69 103 161 ( 6.3 in ) 2 ( 0.1 in ) 2005 1204 663 41 78 124 191 ( 7.5 in ) 83 ( 3.3 in ) Mean ET = 49 inches ; mean estimated ET = 28 inches o c Midday leaf water potential close to harvest for vines in three irrigation treatments in the Merlot vineyard near Madera , CA . Prior to Irrigation treatment Year Harvest 0.4 0.8 1.2 - - - - - - - - - - - - - ( MPa ) - - - - - - - - - - - - - 2001 Aug 16 - 1.40 - 1.15 - 0.93 2002 Aug 22 - 1.41 - 1.23 - 0.98 2003 Sept 11 - 1.46 - 1.28 - 1.04 2004 Aug 19 - 1.48 - 1.20 - 0.89 2005 Sept 11 - 1.33 - 1.14 - 0.80 The effect of irrigation treatment and year on the quantity of applied water to produce one ton of Merlot grown in Madera County . - - - - - - - - - - - - - - Irrigation Treatment - - - - - - - - - - - - - Year 0.4 0.8 1.2 - - - - - - - - - - - ( gallons H O / ton fruit ) - - - - - - - - - - - - 2 2001 35,166 59,298 85,384 56,117 2002 30,306 43,901 69,633 2003 44,630 57,262 102,258 2004 51,478 78,887 73,973 2005 44,785 56,971 - - - - - ( Gallons H O / Gallon Must ) - - - - - 2 ( Water footprint ) ï?  185 349 455 170 gallons of must per ton of fruit The effect of irrigation amount and year on yield of Merlot grown in Madera County . - - - - - - - - - Irrigation Treatment - - - - - - - - - Ave . Effect Year Year 0.4 0.8 1.2 - - - - - - - - - - - - - - - - - - - - - - ( tons / acre ) - - - - - - - - - - - - - - - - - - - - - - 2001 7.4 ( 88 % ) 8.4 ( 99 % ) 8.4 8.0 2002 8.5 ( 69 % ) 11.2 ( 90 % ) 12.4 10.7 2003 5.3 ( 51 % ) 8.4 ( 82 % ) 10.3 8.5 2004 5.7 ( 70 % ) 7.1 ( 87 % ) 8.2 7.0 2005 6.5 ( 55 % ) 9.7 ( 82 % ) 11.9 9.4 6.7 ( 66 % ) 9.0 ( 88 % ) 10.2 Applied water for the 0.4 and 0.8 treatments were 35 ( 9.8 in ) and 68 % ( 19 in ) of estimated ET ( 28 in ) . c Paso Robles Irrigation Strategies : 2002 - 2006 â?¢ SuDI â?? Sustained Deficit Irrigation at 0.375 , 0.56 and 0.75 of estimated ET ( control was 1.12 of c ET ) c â?¢ PRD â?? Partial Rootzone Drying : ( sides alternated every 2 weeks ) â?¢ RDI â?? S to V : deficit irrigation at fraction of ET c from set to veraison , then 1.12 ET from veraison c to harvest . â?¢ RDI â?? V to H : irrigation at 1.12 ET from set to c veraison and then deficit irrigation at fraction of ET from veraison to harvest . c â?¢ Dry Down : water applied every two weeks ( approximately 24 gallons per vine ) Applied water as a percentage of estimated ET c from 2002 to 2006 in a study at J . Lohr winery . Irrigation treatment ( fraction of estimated ET ) c Year 0.375 0.56 0.75 1.12 Applied H O ( % of seasonal estimated ET ) 2 c 2002 30 40 60 80 2003 24 36 48 72 2004 30 46 61 85 2005 22 33 44 66 2006 25 38 50 75 26 39 53 76 - - - - - - - - - - Mean applied H O ( inches ) - - - - - - - - - - 2 176 gallons ï?  4.7 7.0 9.5 13.6 Estimated ET was 18.1 inches . c The effects of irrigation treatment and year on berry wt . of Cabernet Sauvignon grown near Paso Robles . There was a significant interaction between irrigation treatment and year . Irrigation Berry wt . Berry wt . - 1 - 1 Treatment ( g 100 berries ) Year ( g 100 berries ) SuDI 0.375 87 f 2002 91 c SuDI 0.56 97 de 2003 90 c SuDI 0.75 109 b 2004 100 b FI 1.12 116 a 2005 111 a S - V 0.375 97 d 2006 112 a S - V 0.56 104 c Rain Before / After 4 / 1 V - H 0.375 99 d 2004 213 / 0 mm V - H 0.56 104 c 2005 381 / 38 mm DD 93 e 2006 237 / 79 mm The effects of irrigation treatment and year on yield of Cabernet Sauvignon grown near Paso Robles . There was no significant interaction between irrigation treatment and year . Irrigation Yield Yield - 1 - 1 Treatment ( kg 4 vines ) Year ( kg 4 vines ) 72 % 7.76 SuDI 0.375 31.6 c 2002 38.9 b 77 % 5.85 SuDI 0.56 33.4 c 2003 29.3 d 90 % 4.85 SuDI 0.75 39.0 ab 2004 24.3 e 10.5 FI 1.12 43.4 a 2005 52.4 a 6.97 S - V 0.375 33.6 bc 2006 34.9 c S - V 0.56 41.2 a Rain Before / After 4 / 1 V - H 0.375 33.5 bc 2004 213 / 0 mm V - H 0.56 35.3 bc 2005 381 / 38 mm DD 33.9 bc 2006 237 / 79 mm Meridian winery ( Paso Robles ) irrigation / rootstock trial Cabernet Sauvignon grafted onto five rootstocks ( 5C , 110R , Freedom , 140 Ru and 1103P ) were used in the study . Irrigation treatments were various fractions ( 0.25,0.5,0.75,1.0 and1.25 ) of estimated ET . c The trellis was a VSP and vine and row spacings were 6 x 10 ft ( 1.83 x 3.05 m ) Applied water as a percentage of estimated ET c from 1998 to 2001 at Meridian Winery . Irrigation treatment ( fraction of estimated ET ) c Year 0.25 0.5 0.75 1.0 1.25 Applied H O ( % of seasonal estimated ET ) 2 c 1997 - - - - - - - - - - 1998 18 41 64 86 105 1999 19 43 67 91 111 2000 18 40 63 86 104 2001 18 40 63 85 104 18 41 64 87 106 - - - - - - - - - - Mean applied H O ( inches ) - - - - - - - - - - 2 97 gal / vine ï?  2.6 5.9 9.3 12.6 15.4 ET was 44 inches , estimated ET was 14.5 inches . o c The effect of applied water amounts and rootstock on Berry weight of Cabernet Sauvignon at Meridian Winery from 1997 to 2001 . - - - - - - - - - Irrigation Treatment ( fraction of estimated ( ET ) - - - - - - - - - Ave . Eff . c Rootstock 0.25 0.5 0.75 1.0 1.25 Rtstck - 1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Berry weight ( g 100 berries ) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5C 111 122 129 133 143 128 110R 112 120 132 139 145 130 Freedom 115 122 134 147 151 134 140Ru 116 133 142 146 153 138 1103P 119 124 132 146 144 133 Ave . Irr . Eff . 115 124 134 142 147 LSD Irrigation = 4 Rootstock = 5 Interaction = ns 0.05 The effect of applied water amounts and rootstock on yield of Cabernet Sauvignon at Meridian Winery from 1997 to 2001 . ( Greatest yield ~ 8.1 tons / acre ; lowest yield ~ 4.1 tons / acre ) Ave . Eff . - - - - Irrigation Treatment ( fraction of estimated ( ET ) - - - - c Rootstock Rootstock 0.25 0.5 0.75 1.0 1.25 - 1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Yield ( kg 3 vines ) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5C 15.9 66 18.9 78 22.1 91 22.5 93 24.2 20.7 110R 17.0 62 19.5 71 25.4 93 26.2 96 27.4 23.1 Freedom 15.5 54 19.4 67 22.9 79 25.8 89 28.9 22.5 140Ru 20.2 70 19.8 69 23.7 82 24.9 86 28.9 23.5 1103P 18.6 60 21.2 73 25.2 83 27.5 91 30.3 24.6 Ave . Eff . 17.4 62 19.8 71 23.9 86 25.1 90 27.9 Irr . LSD Irrigation = 1.6 Rootstock = 1.5 Interaction = ns 0.05 Values in this color represent % of the highest yield of each rootstock at a particular irrigation treatment . The effects of irrigation treatments , across years and rootstock , on yield of Cabernet Sauvignon grown near Paso Robles and yield as a function of applied water amounts . Irrigation Yield H O / Yield H O / Must 2 2 Treatment ( tons / acre ) ( gal . / ton ) ( gal . / gal . ) 0.25 4.55 15,201 105 0.5 5.27 29,652 204 0.75 6.38 38,739 267 1.0 6.70 50,038 344 1.25 7.42 54,587 376 ( 145 gallons must per ton of fruit ) The effects of irrigation treatments ( applied water amounts at various fractions of ET ) on yield as a function of applied c water amounts on Thompson Seedless grown at the Kearney Ag Center . ( ET is ~ 26.6 in . from budbreak to harvest . ) c Irrigation H O / Yield ( gal . / ton ) H O / Juice ( gal . / gal . ) 2 2 Treatment 1992 1993 1992 1993 0.2 10,686 13,881 63 82 0.4 12,492 15,394 74 91 0.6 14,378 19,837 85 117 0.8 16,739 27,858 99 164 1.0 20,486 38,906 120 229 1.2 25,481 54,035 150 318 1.4 31,435 66,764 185 393 High and low yields in 1992 were 24.3 and 11.1 tons per acre , respectively . The effects of irrigation treatments on yield as a function of ET of Thompson Seedless grown at the Kearney Ag Center . c Other information is as given in previous slide . Irrigation H O / Yield ( gal . / ton ) H O / Juice ( gal . / gal . ) 2 2 Treatment 1992 1993 1992 1993 0.2 22,335 31,461 131 185 0.6 20,966 26,658 123 157 1.0 27,354 49,713 161 292 1.4 35,544 70,366 209 414 ( 170 gallons of juice per ton of fruit ) Final thoughts : â?¢ Row spacing and trellis type are the predominant factors determining potential vineyard water use . Generalizations made concerning season - long average , applied water amounts as a function of location in California and possible reductions in those amounts without causing a loss in vineyard productivity should be viewed with caution . This is why estimates of vineyard ET are important . Final thoughts : â?¢ Fruit / canopy management â?¢ Use of rootstocks / vigor â?¢ Irrigation management â?? deficit irrigation will always increase water use efficiency when based upon applied water amounts , ET based may be different Acknowledgements â?¢ Dan Bosch , Mitchell Kluge , Rich Arnold and Don Williams of Robert Mondavi Vineyards â?¢ John Simpson and Darrin Peterson of Simpson Meadow Vineyards â?¢ Steve Carter , Angie Perry , Carrie McDonnell , Scott Williams and Daniel Shaw of J . Lohr Winery â?¢ Tony Domingos of Meridian Winery and Bob Steinhauer of Beringer - Blass Wine Estates â?¢ American Vineyard Foundation , Viticulture Consortium and California Competitive Grants for partially funding the research projects used in this presentation .