Forage Production Strategies with Limited Water Supplies 2015 Kearney Alfalfa and Forage Field Day Parlier, CA September 18, 2015

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1 Blake Sanden Irrigation & Agronomy, Kern County Dan Putnam Chief of Comic Relief Blaine Hanson Irrigation Specialist, UC Davis UNIVERSITY of CALIFORNIA COOPERATIVE EXTENSION Forage Production Strategies with Limited Water Supplies 2015 Kearney Alfalfa and Forage Field Day Parlier, CA September 18, 2015

2 Why would anyone come up with such a hair-brained idea? Forage Production with Reduced Water California is not building more dams. Meeting increased water demand is going to come through conservation and shifting water supply to higher value uses.

3 Population increase of 10 million in 30 years Year Total Irrigation (MAc): Gravity Sprinkler Micro Ag demand (MAF): Avg Water Cost ($/ac-ft): $18 $85 Kern County Population: Municipal demand (MAF): Ag Demand/Total: 84% 80% Ag Demand (ac-ft/ac): Ag Savings (%): Base 13% Irrigated Acreage & Water Demand in California 1970 to 2000

4 Forage Production with Reduced Water First: a public service message This is your forage.

5 Forage Production with Reduced Water This is your forage on reduced water.

6 Forage Production with Reduced Water I m screwed! Any questions?

7 ELECTRON MICROGRAPH OF STOMATA ON THE UNDERSIDE OF A LEAF. WHY YOU ARE SCREWED: Reduced water, deficit irrigation, causes less turgor pressure in the plant, reduces the size of stomatal openings; thus decreasing the uptake of carbon dioxide and reducing vegetative growth.

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9 Google (images): statewide alfalfa water demand Here s what you come up with the thirstiest guy on the planet! At least he found his boat when the reservoir went dry!

10 Annual alfalfa water demand: 4 to 5.5 MAC (Source: California Department of Water Resources, above figure from Pacific Institute 2012)

11 The irrigation method / system is the ESSENTIAL integrating factor for California farming. Water SOURCE SOURCE / / SUPPLY SUPPLY SALTS SALTS / / QUALITY QUALITY REQUIRED REQUIRED AMENDMENTS AMENDMENTS COST COST Crop LIFE LIFE CYCLE CYCLE & WATER WATER USE USE (ET) (ET) ROOTING ROOTING CHARACTERISTICS CHARACTERISTICS DESIRED DESIRED STRUCTURE STRUCTURE / / SPACING SPACING HARVEST HARVEST REQUIREMENTS REQUIREMENTS FIELD FIELD TRAFFIC TRAFFIC Soil TOPOGRAPHY TOPOGRAPHY TEXTURE TEXTURE INFILTRATION INFILTRATION RATE RATE DRAINAGE DRAINAGE SALTS SALTS / / QUALITY QUALITY AMENDMENTS AMENDMENTS / / COST COST California California crops crops sit sit most most firmly firmly on on a a chair chair with with 44 legs! legs! System IRRIGATION IRRIGATION METHOD METHOD DISTRIBUTION DISTRIBUTION PATTERN PATTERN IRRIGATION IRRIGATION FREQUENCY FREQUENCY MONITORING MONITORING MAINTENANCE MAINTENANCE / / REPAIR REPAIR OPERATING OPERATING COST COST CAPITAL CAPITAL COST COST

12 Forage Production with Reduced Water 4 3-point sermon: Understanding soil water holding characteristics Crop water requirements (ET), CIMIS Monitoring soil moisture & irrigation uniformity Forage crop salinity tolerance

13 Check your dirt! SOIL PROFILE SOIL TEXTURE Analysis: SP saturation % ph 7.8 EC e 2.0 ds/m Texture Silty Clay Loam Boron Leaching Curve (Hoffman, 1980) SOIL SURVEY BACKHOE PITS AUGER, PUSH PROBE

14 Backhoe Pits the Worm s Eye View!

15 Check your dirt! It has more secrets than the CIA.

16 The dirt is the thing. Know your soil! Soil Texture Field Capacity (in/ft) Wilting Point (in/ft) Available Soil Moisture (in/ft) Avg Drip Subbing Diameter from 1 to 4' Depth (ft) *Moisture Reserve (gals) Sand Loamy Sand Sandy Loam Loam Silt Loam Sandy Clay Loam Sandy Clay Clay Loam Silty Clay Loam Silty Clay Clay *This is the maximum gallons of water stored to a 4' depth beneath a single drip emitter. In fine textured soils, the wetted volume of one emitter merges with another on the same hose and final gallons of moisture reserve per emitter will be less than the number shown in the table. Plant stress will usually be seen when about 50% of this reserve has been used. Ref: Ratliff LF, Ritchie JT, Cassel DK Field-measured limits of soil water availability as related to lab oratory-measured properties. Soil Sci Soc Am. 47:770-5.

17 So what s the big deal with about monitoring soil moisture? Doesn t the field always take in the same amount of water? One answer: Each field, crop, climate and grower has unique characteristics. The majority of acreage in CA is still flood irrigated. Infiltration is often uncertain maybe 1.5 inches up to 12 inches depending on the mix of soil and water chemistry.

18 Many Class I sandy loam soils planted to almonds in Kern County have water penetration problems due to low aggregate stability from loss of clays at the surface and irrigation with extremely low salinity water.

19 COMBINED CRUSTING AND DISPERSION AFTER LAYBY IN COTTON After layby cultivation infiltration over a 12 hour set went from 4.3 to 0.4 from 6/16 to 7/20/96. Water run gypsum on 8/4 improved infiltration to 1.3. Cumulative Infiltration (in) Wasco Sandy Loam (Shafter Field Station) 6/16 6/25 8/4-Gypsum 7/ Time (hrs)

20 Forage Production with Reduced Water 3-point sermon: Understanding soil water holding characteristics Crop water requirements (ET), CIMIS Monitoring soil moisture, & irrigation uniformity

21 Crop water use is made up of EVAPORATION (E) from the wet soil and leaves and TRANSPIRATION (T), hence ET

22 CALIFORNIA IRRIGATION MANAGEMENT INFORMATION SERVICE Courtesy of Mark Anderson, DWR

23 Courtesy of Mark Anderson, DWR CIMIS station locations around California as of 2002

24 CIMIS Map of California Climate Zones and Monthly ETo water.ca.gov

25 The whole Central Valley covers Zones 12 to 16: for an normal year ETo of 53.3 to 62.5 in/yr, with most 53 to 58 inches.

26 Calculating ET for crops: ET crop = ET o * K c * E f ET o = reference crop (tall grass) ET K c = crop coefficient for a given stage of growth as a ratio of grass water use. May be 0 to 1.3, standard values are good starting point. E f = an environmental factor that can account for immature permanent crops and/or impact of salinity. May be 0.1 to 1.1, determined by site.

27 DATE "Normal Year" grass potential evapotranspiration (ETo), forage crop coefficients and ET for the southern San Joaquin Valley Pasture *ETo (inch) 2 Alfalfa Silage 4/1-8/25 1 Crop Coefficient Values (Kc) Silage 6/15-10/15 3 Sudan Winter Forage Triple Crop 2 Alfalfa 4 Normal Year Crop ET (inches) Silage 4/1-8/25 Silage 6/15-10/15 3 Sudan Winter Forage 1/ / / / / / Plant / Silage / Plant / / Plant / / / / Sudan / / / / / / / Plant TriGrain / / / TOTALS *Jones, D.W., R.L. Snyder, S. Eching and H. Gomez-McPherson California Irrigation Management Information System (CIMIS) Reference Triple Crop

28 Forage Production with Reduced Water Normal Year Alfalfa ET (dips indicate cutting schedule) 2.5 Pasture (ETo): 57.9 in Weekly Alfalfa ET: 55.1 in 2.0 Weekly ET (in) Weekly Normal Year ETo & Alfalfa ET for the Southern San Joaquin Valley (Non-dormant, cut every 28 days.) /31 1/28 2/25 3/24 4/21 5/19 6/16 7/14 8/11 9/8 10/6 11/3 12/1 12/29

29 ELECTRON MICROGRAPH OF STOMATA ON THE UNDERSIDE OF A LEAF So what s the point? ET = YIELD

30 Forage Production with Reduced Water Alfalfa Yield/ET Production Functions for Various Regions 16 San Joaquin Valley Alfalfa Tonnage & ET Avg Annual t/ac = 0.2 (Inches ET) YIeld (t/ac) Alfalfa ET (in)

31 Forage Production with Reduced Water Production Functions for YIeld (t/ac) Record Yuma, AZ: inches Record Yuma Alfalfa Tonnage & Applied Water Annual t/ac = (Irrig) (Irrig) (Irrig) R2 = Mesa Sirsa Lew Applied Water (in) Yuma: 140 / 23 = 6.1inch/ton YIeld (t/ac) Typical Tulelake: 6 ton production Tulelake Alfalfa Tonnage & Applied Water Annual t/ac = (Irrig) (Irrig) (Irrig) Applied Water (in) Tulelake: 25 / 6.2 = 4.0 inch/ton

32 Changes in Mid-west Alfalfa WUE Spring to Fall Undersander, 1987 Courtesy B.R. Lindenmayer, CO State Univ WUE = 2.8 in/ton WUE = 6.7 in/ton WUE = 6.7 in/ton WUE = 2.1 in/ton

33 Forage Production with Reduced Water Water Use Efficiency (WUE): = Water Beneficially Used Total Water Applied = Yield Applied (ET+leaching) = Crop Drop WUE can vary by season, variety, field fertility level and % available moisture.

34 Loggers have to be downloaded every 3 weeks and instrument area hand cut with each cutting Forage Production with Reduced Water Alfalfa Deficit Irrigation, Kern County

35 Forage Production with Reduced Water 8/24/06: condition of deficit treatment (irrigation 7/18) compared to no stress (irrigation 7/18 and again 8/11)

36 Forage Production with Reduced Water 8/24/06: condition of deficit treatment (irrigation 7/18) compared to no stress (irrigation 7/18 and again 8/11)

37 Alfalfa Daily ETc for Full & Deficit Irrigation West (Full Irrig) Daily ETc (mm) East (Aug Deficit) Daily ETo (mm) Total ETc 5/23 to 10/29 Full irrigation = 941mm (37.04 inches) Irrig 6/22 Deficit = 863mm (34.01 inches) Irrig 5/2 Irrig 6/6 Irrig 7/15 Belridge ETo = 849mm (33.40 inches) Irrig 8/11 (Full only) Irrig 9/6 (All) Irrig 9/19 (Deficit 12 hrs) Daily ETc (mm/day) th cut 10/8/06 ET 7.22" 6.85" st Cut 4/25 Cloudy 2nd cut 5/30/06 ET West missing data 8.73" 3rd cut 7/6/06 ET 10.8" 10.2" 4th cut 8/3/06 ET 7.64" 7.31" 5th cut 8/30/06 ET 6.79" 5.39" 0.2" rain 10/13 4/16 4/30 5/14 5/28 6/11 6/25 7/9 7/23 8/6 8/20 9/3 9/17 10/1 10/15 10/29 Day of year

38 Alfalfa Full ETc & CIMIS Potential Grass ETo Alfalf Full Irrig Daily ETc (mm) CIMIS Daily Grass ETo (mm) FULL IRRIGATION Daily ETc (mm/day) Daily Crop Coefficient (Kc) /16 4/30 5/14 5/28 6/11 6/25 7/9 7/23 8/6 8/20 9/3 9/17 10/1 10/15 10/29 Day of year FULL IRRIGATION Irrig 5/2 1st Cut 4/25 Irrig 6/6 2nd cut 5/30/06 ET West missing data 8.73" Irrig 6/22 Total ETc & CIMIS -- 5/23 to 10/29 Full irrigation = 941mm (37.04 inches) Belridge ETo = 849mm (33.40 inches) Season Average Kc = rd cut 7/6/06 ET 10.8" 10.2" Irrig 7/15 Irrig 8/11 (Full only) 4th cut 8/3/06 ET 7.64" 7.31" 4/16 4/30 5/14 5/28 6/11 6/25 7/9 7/23 8/6 8/20 9/3 9/17 10/1 10/15 10/29 Day of year Irrig 9/6 (All) 5th cut 8/30/06 ET 6.79" 5.39" 0.2" rain 10/13 Irrig 9/19 (Deficit 12 hrs) 6th cut 10/8/06 ET 7.22" 6.85"

39 Forage Production with Reduced Water Kern County Deficit Irrigation Trial Pictures 8/30/07 Irrigation off 20 days Hay cut 8/29 Water back 9/5 Irrigation off 45 days at cutting. Total 50 days off.

40 Forage Production with Reduced Water Production Functions for Kern County Alfalfa Deficit Irrigation Trial Cumulative Alfalfa Yield (t/ac) Alfalfa ET 1/1 to 10/9 2006: inches 2007: inches 2007 t/ac = 0.194(inches ET) 7 cuttings (R 2 = 0.965) 2006 t/ac = 0.171(inches ET) 6 cuttings (R 2 = 0.984) Cumulative ET (inches) 2007 Cum Yield 2006 Cum Yield 2006: 5.8 inches ET/ton alfalfa 2007: 5.2 inches ET/ton alfalfa Increased WUE of 15% over 2006

41 Forage Production with Reduced Water 3-point sermon: Understanding soil water holding characteristics Crop water requirements (ET), CIMIS Monitoring soil moisture, & irrigation uniformity

42 Forage Production with Reduced Water Equipment for checking soil Moisture Most Common Method

43 Forage Production with Reduced Water Tulelake irrigation consultant with soil probe

44 3 foot push or slide hammer probe ($150-$250)

45 Hand-powered twist augers ($150 - $300)

46 SOIL TEXTURE DETERMINES AVAILABLE WATER HOLDING CAPACITY SOIL TEXTURE FEEL METHOD AWHC = %Volume = inch depth of water 1 foot depth of soil

47 Guide for Estimating Actual Available Field Soil Moisture by the "Feel" Method. Coarse (loamy sand) SOIL TEXTURE CLASSIFICATION Sandy Medium (sandy loam) (loam) Fine (clay loam, silty clay loam) Available Water (AW) in the Soil by Appearance (inches/foot soil) in/ft in/ft in/ft in/ft AW AW AW AW Deficit Leaves wet outline Appears very dark Appears very dark Appears very dark, leaves 0 On hand when 1.0 leaves wet outline 1.6 leaves wet outline 1.9 slight moisture 2.2 squeezed. on hand, makes a on hand, will ribbon on hand when squeezed, will short ribbon (0.5- about 1 2 inches. ribbon > 2 inches inch) 1.7 Appears moist, 0.7 Makes a weak ball. Appears slightly moist, sticks together slightly. 0.4 Quite dark color makes a hard ball. 1.2 Dry, loose, flows thru fingers. (wilting point) 0 Slightly dark color Very slight color 0 due to moisture. (wilting point) Dark color, forms a plastic pall, slicks when rubbed. 1.4 Dark color will feel slick And ribbons easily Fairly dark color, makes a good ball 1.0 Quite dark, forms a hard ball 1.2 Quite dark, will make thick ribbon may slick when rubbed. makes a weak ball 0.7 Fairly dark, forms a 1.0 a good ball Lightly colored by moisture, will not 0.4 ball. Slightly dark, forms 0.6 weak ball Fairly dark, makes a good ball. 1.1 Will ball, small clods will flatten out rather 0.7 Lightly Colored, small clods crumble 0.2 Slightly dark, clods 0.4 Fairly easily. Crumble. Slight color due to moisture, small colds hard (wilting point). Some darkness due to 0 unavailable moisture, clods are hard, cracked (wilting pt) * AW@FC: Available Field Capacity = the available water a soil can store against gravity after irrigation and drainage. Adapted from: Merriam, J.L Field method of approximating soil moisture for irrigation. Am. Soc. Agri. Engr. Vol. 3. No

48 Watermark blocks estimate soil moisture tension (matric potential) using electrical resistance and require no maintenance (~$30). However, a separate meter or logger ($200+) is needed to read the device.

49 Forage Production with Reduced Water Loggers used in Kern County irrigation projects

50 Typical field layout for flood systems. Total soil moisture monitoring system cost: $ Bed 18 Watermark Group 36 Neutron Probe Access Tube (2 x 6 Class 125 PVC) Fig. 1. Typical field layout of monitoring sites with surface irrigation. Spacing of Watermark sensor groups varied according to irrigation system, but usually 18, 36 and 60 inch depths. (Not to scale.)

51 Watermark Readings: Full Irrigation Sandy Loam Alfalfa 2 Irrigations per cutting peak season /1 4/29 5/27 6/24 7/22 8/19 9/16 10/14 11/11 Soil Moisture Tension (cb) " 24" 48" Wadel Alfalfa - Full Irrigation Wasco Sandy Loam. Border Flood 150' from HEAD Season Total 9.72 t/ac Last Cut 10/10/ /1 4/29 5/27 6/24 7/22 8/19 9/16 10/14 11/11 Soil Moisture Tension (cb) " 24" 48" Wadel Alfalfa - Full Irrigation Wasco Sandy Loam. Border Flood 750' from HEAD (TAIL END)

52 Watermark Readings: Deficit Irrigation Sandy Loam Alfalfa 1 Irrigation only for July and August cuttings /1 4/29 5/27 6/24 7/22 8/19 9/16 10/14 11/11 Soil Moisture Tension (cb) " 24" 48" Wadel Deficit - 1 Irrigation in Jul and Aug Wasco Sandy Loam. Border Flood 150' from HEAD Season Total 9.79 t/ac Last Cut 10/10/ /1 4/29 5/27 6/24 7/22 8/19 9/16 10/14 11/11 Soil Moisture Tension (cb) " 24" 48" Malfunction of 12" sensor Wadel Deficit - 1 Irrigation in Jul and Aug Wasco Sandy Loam. Border Flood 750' from HEAD (TAIL END)

53 Forage Production with Reduced Water Irrigation distribution uniformity (DU) determined by soil infiltration rate, flow down the check and set duration. DU (%) = 100 * low quarter infiltration Average field infiltration Head Possible stress N leaching, water logging Stressed plant growth Too little water Rootzone Depth (m) hrs 12 hrs 18 hrs Tail no leaching 24 hrs Deep percolation lost water & N fertilizer

54 Uniform stands with high irrigation efficiency require large/fast heads of water and usually a tail water return system. Forage Production with Reduced Water

55 Forage Production with Reduced Water Irrigation non-uniformity can have severe impacts on water use and yields

56 Forage Production with Reduced Water Impact of irrigation distribution uniformity (DU) Field Qtr on field applied water and alfalfa yield Qtr Irrig by Avg Depth (in) Qtr Yield by Avg Depth (t/ac) 70% DU Wettest Wet Drier Dry Field Average Yield (t/ac): % DU Wettest Wet Drier Dry Field Average Yield (t/ac): % DU Wettest Wet Drier Dry Field Average Yield (t/ac): Alfalfa Yield (t/ac) Yield (t/ac) = x x R2 = Applied water(in)

57 Impact of Distribution Uniformity (DU) on Water Applied to the Field and Final Alfalfa Yields Field Qtr Qtr Irrig by Avg Depth (in) Qtr Yield by Avg Depth (t/ac) 70% DU Wettest Wet Drier Dry Field Average Yield (t/ac): % DU Wettest Wet Drier Dry Field Average Yield (t/ac): % DU Wettest Wet Drier Dry Field Average Yield (t/ac): Alfalfa Yield (t/ac)

58 Net Revenue for Average SJV Alfalfa Yields for $30, $60 and $90/ac-ft Water Costs and Different Field Irrigation Uniformities Assumptions: All base costs without water ($/ac): $ No. of cuttings: 8 Cost of cut and rake ($/ac/cutting): $12.00 Custom bale ($/ton): $10.25 Harrow bed ($/ton): $4.00 Hay price ($/ton): $ Improving DU from 70 to 80% increases net income by 48 inches applied water and $60/ac-ft. Net Income ($) $30/ac-ft $60/ac-ft $90/ac-ft Yield (t/ac) % DU Average Applied Water (inches) Net Income ($) $30/ac-ft $60/ac-ft $90/ac-ft Yield (t/ac) % DU Average Applied Water (inches)

59 Forage Production with Reduced Water Assess Water Productivity in terms of most $/ac-ft return when water supply is the most limiting factor. ET (inches) Yield (ton/ac) Price ($/ton) Gross ($) Water Productivity ($/in) Water Value ($/ac-ft) Alfalfa (7 cuts) 55 9 $180 $1,620 $29.45 $353 Silage 4/1-8/ $28 $840 $24.57 $295 Silage 6/15-10/ $28 $700 $24.89 $299 Sudan (3 cuts) $120 $1,200 $28.93 $347 Winter Forage $24 $408 $26.02 $312 Wheat grain $220 $704 $33.52 $402

60 Forage Production with Reduced Water CONCLUSIONS: Use Normal Year ET schedules to estimate forage crop water consumption Understand AND CHECK the depth of infiltration during irrigation events Knowing this depth and normal ET, check head and tail soil moisture to best schedule the next irrigation

61 Forage Production with Reduced Water CONCLUSIONS (continued): Increasing DU from 70 to 80% can return a SJV grower hay prices of $120/ton. Increasing DU from 70 to 90% will return $90 to $110/ac Alfala ET in the SJV uses about 5.5 inches/ton. Summer fallow of hay will cost you 2 to 3 tons/ac to save a foot of water, but the stand will be fine if you rewater for a fall cutting. This is not the case for

62 Imperial Valley Where d my stand go?! (Excessive heat scorches crowns and hurts stand when cover and ET decrease)

63 CONCLUSIONS (concluded at last): Total water use is least with winter grain/forage crops and provides high water productivity ($/inch). Organize all data for each field in a water balance spreadsheet. Install a tailwater return system to improve DU, avoid scald and phytophthora Stay profitable so you can make it to the next CA Alfalfa Symposium and buy Dan a drink! Forage Production with Reduced Water