Drought Irrigation Strategies For Pistachio. David A. Goldhamer Robert H. Beede

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1 Drought Irrigation Strategies For Pistachio David A. Goldhamer Robert H. Beede

2 Tree Response To Water Stress Sustained Deficit Irrigation; Mid 1980s Regulated Deficit Irrigation; 1990s-Current Optimal RDI Strategies for Different Drought Scenarios

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7 Reasons for Droughts 1) Weather 2) Government

8 Traditional Approaches For Reducing Agricultural Water Use 1. Changing irrigation systems. 2. Improving management.

9 Traditional Scheduling Concepts 1) Soil/Plant based monitoring. 2) Water budget.

10 Water Budget ETc = Kc x ETo Orchard Water Use = Crop Coefficient x Reference Crop Water Use

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12 Reducing Non-Traditional Agricultural Approach Water For Use Reducing Agricultural Water Use Reducing consumptive use; evapotranspiration (ETc)

13 Can we reduce Surface Evaporation?

14 Irrigation Frequency vs. Duration Wet surface as infrequently as possible. Insure that when you irrigate with longer duration of application, don t overirrigate.

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17 Can we reduce Transpiration?

18 CO 2 Atmosphere H 2 O O 2 6 CO H 2 O Light C 6 H 12 O 6 +6 O 2 +6 H 2 O (Sugar)

19 Nobel Lecture So today, we dumped another 70 million tons of global-warming pollution (CO 2 ) into the thin shell of atmosphere surrounding our planet, as if it were an open sewer. Albert R. Gore Nobel Prize Acceptance Lecture Oslo, Norway, 10 December 2007

20 CO Pollution 2 Atmosphere Open Sewer H 2 O O 2 Pollution+ 6 CO H 2 O Light C 6 H 12 O 6 +6 O 2 +6 H 2 O (Sugar)

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22 30 Alfalfa Production Function; New Mexico Alfalfa Yield (t/ha) y = 0.136x R 2 = Sammis (1981) Evapotranspiration (cm)

23 Sorghum Production Function; S. Great Plains Grain Yield (kg/ha) y = 15.2x Stewart (1985) Seasonal ET (mm)

24 Jan 1-15 Jan Feb 1-15 Feb Mar 1-15 Mar Apr 1-15 Apr May 1-15 May Jun 1-15 Jun Jul 1-15 Jul Aug 1-15 Aug Sept Sept Oct 1-15 Oct Nov 1-15 Nov Dec 1-15 Dec Mature Orchard Water Use (ETc); Lost Hills Citrus Almond Pistachio Orchard Water Use (inches per period)

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26 Effects of Sustained Deficit Irrigation Late 1980s; Kettleman City Dryland 25% ETc (11.5 inches) 50% ETc (23 inches) 75% ETc (35 inches) 100% ETc (46 inches)

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31 Drought Tolerance: = Ability to Survive = High Productivity

32 Regulated Deficit Irrigation (RDI) * * * Work in Australia and New Zealand on stone fruits. Identified stress tolerant growth stages; usually during slow fruit growth. Purposely imposed stress during these periods in order to save water and achieve horticultural benefits.

33 Stage 1 Stage 2 Stage 3 Fruit Dry Weight Gain Rate (g/d) Apr 16 May 1 May 16 May 31 Jun 15 Jun 30 Jul 15 Jul 30 Aug 14 Aug 29

34 Effects of Regulated Deficit Irrigation Early 1990s; Kettleman City Treatments: Evaluate sensitivity of each crop growth stage to water stress. Test effectiveness of various degrees of stress during Stage 2 and postharvest.

35 Mean ( ) Yield and Component Results Blanks Mechanical Yield of Split and Total Removal Dry,Split Irrigation Nut Aborted Shell Nut of Split Nuts at Water Use Weight Nuts Splitting Load Nuts Harvest Efficiency Treatment (g/nut) (% nut load) (% filled nuts) (No./tree) (% splits) (lb/acre) (gals H20/lb product) 0% Stage b* 21.5 ab 87.8 d bc 2828 d 296 bc 0% Stage bc 22.0 ab 73.6 b bc 2239 bc 296 bc 0% Stage a 27.6 c 43.6 a a 1014 a 419 a 0% Postharvest 1.30 bc 22.8 abc 78.8 bc bc 2451 bcd 350 ab 50% Stage 2; 25% PH 1.30 bc 21.2 ab 81.7 cd bc 2744 cd 256 c Control 1.32 c 22.5 ab 79.5 bc bc 2714 cd 333 ab NSD * Values followed by the same letter are not statistically different at p=0.05.

36 Mean ( ) Yield and Component Results Blanks Mechanical Yield of Split and Total Removal Dry,Split Irrigation Nut Aborted Shell Nut of Split Nuts at Water Use Weight Nuts Splitting Load Nuts Harvest Efficiency Treatment (g/nut) (% nut load) (% filled nuts) (No./tree) (% splits) (lb/acre) (gals H20/lb product) 0% Stage b* 21.5 ab 87.8 d bc 2828 d 296 bc 0% Stage bc 22.0 ab 73.6 b bc 2239 bc 296 bc 0% Stage a 27.6 c 43.6 a a 1014 a 419 a 0% Postharvest 1.30 bc 22.8 abc 78.8 bc bc 2451 bcd 350 ab 25% Stage 2; 50% PH 1.32 c 21.0 ab 75.9 bc bc 2400 bcd 303 bc 25% Stage 2; 25% PH 1.32 c 22.1 ab 78.1 bc bc 2412 bcd 296 bc 0% Stage 2; 25% PH 1.28 bc 24.6 bc 75.3 bc b 2150 b 288 bc 50% Stage 2; 50% PH 1.30 bc 19.0 a 81.0 bcd c 2624 bcd 295 bc 50% Stage 2; 25% PH 1.30 bc 21.2 ab 81.7 cd bc 2744 cd 256 c Control 1.32 c 22.5 ab 79.5 bc bc 2714 cd 333 ab NSD * Values followed by the same letter are not statistically different at p=0.05.

37 Pistachio RDI Experiments in SSJV Kettleman City, Atlantica, Madera, Atlantica, McFarland, Atlantica, Lost Hills, Atlantica, Parlier, Atlantica, Parlier, PG1, Madera, PG1, 04-Current

38 Mean of Last 2 Exp. Yrs; All Stress Stages Yield; Dry In-Shell (% of Control :1 Kettleman City, Atl., '89-'92 Madera, Atl., '92-'95 Lost Hills, Atl., '93-96 McFarland, Atl., '93-'96 Parlier, Atl., '03-'06 Parlier, PG1, '03-'06 Madera, PG1, '04-' Evapotranspiration (% of Control)

39 Mean of Last 2 Exp. Yrs; All Stress Stages 110 Yield; Dry In-Shell (% of Control :1 Kettleman City, Atl., '89-'92 Madera, Atl., '92-'95 Lost Hills, Atl., '93-96 McFarland, Atl., '93-'96 Parlier, Atl., '03-'06 Parlier, PG1, '03-'06 Madera, PG1, '04-' Evapotranspiration (% of Control)

40 Only Stage 2 and PH Stress 110 Y = 1.26x 12.9 R2 = 0.77 Yield, Dry In-Shell (% of Control :1 Kettleman City, Atl., '89-'92 Madera, Atl., '92-'95 Lost Hills, Atl., '93-96 McFarland, Atl., '93-'96 Madera, PG1, '04-' Evapotranspiration (% of Control)

41 To convert % to yield; ETc values, Assume: 1) Yields will range from 1000 to 6000 lb/ac. 2) Potential ETc (consumptive use) is 46 inches (3.83 acre-ft). 3) We will stress only Stage 2 and postharvest. How do we estimate impact of stress on yields and determine value of water?

42 Cropping Load Impacts on Water Prod Yield; Dry In-Shell (lb/ac) lb/af 1647 lb/af 1317 lb/af 988 lb/af 659 lb/af 329 lb/af 6000 lb/ac 5000 lb/ac 4000 lb/ac 3000 lb/ac 2000 lb/ac 1000 lb/ac Evapotranspiration (acre-ft)

43 40" Case 36" Case 24" Case 18" Case Normal Normal RDI RDI RDI RDI ETo Kc ETc Factor Factor Factor Factor (inches) (inches) (%) (%) (%) (%) Apr Apr May May Jun Jun Jul Jul Aug Aug Sept Sept Oct Oct Nov Seasonal ETc

44 Are there useful indicators of tree stress?

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46 Fully Irrigated; July 9

47 Stressed; July 9

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51 Conclusions from Pistachio Irrigation Studies Pistachio trees are extremely drought tolerant. Pistachio trees have the potential to use large amounts of water. Mid May thru early July (Stage 2) is most stress tolerant, followed by postharvest, and leafout to mid May (Stage 1); early July to harvest (Stage 3) is least stress tolerant.

52 Thank You