Irrigation Strategies for Water-Short Years or Efficient Water Use

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1 Irrigation Strategies for Water-Short Years or Efficient Water Use Northern Utah Water Conference Logan, Utah April 2, 2014 Presentation by L. Niel Allen Extension Irrigation Engineer

2 Definition of Water Use Efficiency Yield per unit of water applied (example tons/acre-foot of applied water) Yield per unit of crop ET (example tons/acre-foot of ET) Yield or production per unit of water diverted (incorporates irrigation conveyance and distribution) Yield per unit of precipitation (incorporates practices that reduce precipitation runoff and deep percolation)

3 When are Irrigation Strategies for Improved Water Use Efficiency Important? Limited irrigation water supplies Allocation of water between different crops High irrigation water costs Drought Always

4 Presentation Overview Irrigation System Improvements Strategies to improve water use efficiency General Irrigation Scheduling Alfalfa Small Grains Pasture, vegetables, fruit Safflower

5 Strategy Improve Irrigation System Coefficient of Uniformity (Sprinklers)

6 Irrigation Uniformity Yield Uniformity The yield impact is the obvious. Some yield impacts are as real but not as obvious.

7 Irrigation Depth (in) 30 Irrigation Depth Distribution (80% Coefficient of Uniformity) Irrigation Depth Distribution (80% Coefficient of Uniformity) Average Irrigation of 15 inches

8 Irrigation Depth (in) Irrigation Depth Distribution 50 % of Area Fully Irrigated Area Receiving less than Indicated Depth (%) CU=70% CU=80%" CU=90% Assumes ET from Irrigation of 15 inches For 15 inches of irrigation water (at 5 acre-inches/ton) 2.72 tons/acre of alfalfa for 90% uniformity 2.53 tons/acre of alfalfa for 80% uniformity 2.39 tons/acre of alfalfa for 70% uniformity

9 Irrigation Depth (in) Irrigation Depth Distribution 75 % of Area Fully Irrigated Area Receiving less than Indicated Depth (%) CU=80%" CU=90% CU=70% For the same yield it takes about 16 inches with a 90% uniformity, 18 inches for a 80% uniformity, and 22 inches for a 70 percent uniformity.

10 10 Efficient Water Use for all Crops Improve Irrigation System Uniformity (minimize deep percolation) Replace sprinklers, gaskets, and fix leaks Upgrade irrigation system Level fields to uniform and proper grade Adjust furrow or border flow rate Irrigation Scheduling (minimize crop stress and deep percolation) Crop Rotation An excellent farmer told me - The best thing about growing green beans is the crop of wheat that follows. Shallow rooted crops (onions, beans, potatoes, etc.) followed deep rooted crops (small grains, safflower, field corn).

11 Basic Principles Alfalfa Alfalfa uses water is most efficient during spring growth (1 st and perhaps 2 nd cutting). About 5 acre-inches of ET per ton (1 st cutting) About 7 acre-inches of ET per ton (later cuttings) Under-irrigation results in higher irrigation efficiencies (slight deficit irrigation) Better to stop watering alfalfa than to just keep it a dull green with little or no growth. Most alfalfa varieties will go into dormancy with no long term impact. Alfalfa is generally considered drought tolerant. 11

12 Basic Principles for Alfalfa (Continued) Focus on most productive alfalfa land (best soils, best alfalfa stem density, least weeds, youngest alfalfa, best irrigation systems, best variety). Focus on land with most efficient irrigation application. Extra water does not produce extra yield. Enough but not extra 12

13 13 Limited Irrigation of Alfalfa in the Great Plains and Intermountain West Troy Bauder, Neil Hansen, Brad Lindenmeyer, Jim Bauder, and Joe Brummer

14 Irrigation Strategy for Wheat or Barley Don t stress your crop, but no need to have a full soil moisture profile at harvest. It takes about 3 inches from soft dough to harvest. In general you can stop irrigating at soft dough. Another irrigation of about 1 inch may be needed. An advantage of a pivot over wheel line is that you can maintain the entire field near field capacity so that at soft it doesn t take a week or more to irrigate. Use irrigation scheduling 14

15 Other Important Considerations (Small grains) Soil tillage to reduce runoff and soil moisture evaporation Planting dates (plant early as possible in spring fall is better for wheat) Irrigation scheduling Variety has an impact on yield and water use efficiency. Soil fertility has an impact on yield and water use efficiency. Water is used more efficiently when nutrients are available. 15

16 ET (inches) Last Irrigation of Wheat Information Water Use and Stages of Winter Wheat Stop Irrigation with Full Soil Moisture Profile Maturity Harvest 15 Flowering Milk Dough 10 Boot Stage Jointing 5 Spring growth 0 1-Apr 1-May 31-May 30-Jun 30-Jul 29-Aug 16

17 17 Scheduling the Last Irrigation on Wheat and Barley Howard Neibling and Zahid Qureshi, University of Idaho

18 Pasture Early water is the most important (cool season grasses). Provide proper fertilization Don t over graze. Consider the variety of grass if you are in a deficit irrigation condition. Bromegrass and wheatgrass were more drought tolerant than tall fescue or orchardgrass, but they didn t tolerate full-season irrigation, and when fully irrigated their stands were dramatically reduced. Orchardgrass tolerated a single season of deficit irrigation but over several years it didn t persist as well as tall fescue. (Orloff and Putnam, UC 2010) Irrigation Scheduling 18

Vegetables Best Strategy is to have an irrigation system with good uniformities and flexibility. Many high value vegetable crops (i.e. green beans, fresh peas, sweet corn) are harvested during a high water use period.

19 Vegetables Best Strategy is to have an irrigation system with good uniformities and flexibility. Many high value vegetable crops (i.e. green beans, fresh peas, sweet corn) are harvested during a high water use period. Don t stress these crops prior to harvest time. Maintain adequate soil moisture, especially during critical development periods. 19

20 Fruit Production Best Strategy is to have an irrigation system with good uniformities and flexibility. Consider micro-irrigation Many high value crops are harvested during a high water use period, so don t sacrifice quality due to irrigation Maintain adequate soil moisture. 20

21 Safflower Irrigation Research Questions Investigated: 1. When and how often should safflower be irrigated? 2. At what growth stage should irrigation be terminated? and 3. How does irrigation impact Alternaria leaf spot?

22 Greenville Utah Agriculture Experiment Farm, North Logan, Utah (field in 2011)

23 800 East Irrigation Plot Layout Safflower Irrigation Research (2013) Greenville Farm First Irrigation 1800 North A B C D E F Treatments No irrigation One irrigation (elongation) Two irrigations (elongation and branching) Three irrigations (elongation, branching, flowering). 12 Plots are 50 feet by 210 feet 13 Irrigation buffer - not used Irrigation treatment Sprinkler Line Main Line

24 2013 Cropping Information Pre-plant fertilizer application of 70 lbs N per acre April 22: Treated with Sonalan for weed control (2 pints per acre) April 25: planted Seeding rate of 20 lbs per acre Variety is #208 May 7: cotyledon leaf stage June : 1 st irrigation (2.96 inches net avg.) June 28 July 2: 2 nd irrigation (3.27 inches net avg.) July 18-19: 3 rd irrigation (3.27 inches net avg.)

25 Cropping Information August 3: Obtained imagery of field. August 9: Fungicide application on half of each plot (Quadris Flowable) at 12 oz. per acre and (Exit Activator Adjuvant) at about 6 oz. per acre. Oct 9: Harvested 9 of 48 sub-plots (a portion of the east side) Combine broke and then it rained. Oct 21: Harvested remainder of plots Total yield of field (all buffers and plots) was 38,000 lbs or about 2,990 lbs. per acre

26 Data Collected Weather data from USU Greenville Farm station Initial soil moisture samples taken at 3 locations on May 10. Soil moisture samples taken every two weeks at 6 locations June 7 through September 3. Yield data for plots Oil content, bushel weight, moisture percent Seed Color Score color scale, dark ends, papus, immature seeds, slight yellowing, sprouting

27 May 7 May 21

28 May 29 June 7

29 June 17 (first Irrigation June 11) June 24

30 July 9 (2 nd Irrigation on June 28) July 9 (two irrigations)

31 July 9 (no irrigations)

32 July 9 (two irrigations, slight Alternaria leaf spot

33 July 15

34 Differences in maturity, branching, and number of seed heads July 15 (2 irrigations, 1 irrigation, and no irrigation)

35 July 18 (third and last irrigation)

36 July 22 (3 irrigations) July 22 (no irrigations)

37 July 30 (3 irrigations, Fungicide was applied August 9)

38 July 30 (no irrigation east side) No signs of Alternaria

False Color Image (red is well irrigated) 0 1 2 0 3 0 0 1 3 0 3 1

39 False Color Image (red is well irrigated) August 3 (Aerial Photo and Irrigation level)

40 Difference between area treated with and without fungicide September 19

41 October 18 (harvest)

42 Yield (lbs./ac.) Safflower Yields Safflower Yield for Irrigation Levels 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1, Irrigation Amounts (inches)

43 Yield (lbs/acre) Average Yields for by Irrigation Levels 4,000 Safflower Yields v Number of Irrigations Greenville Farm ,500 3,000 2,500 2,000 1,500 1, I-0 I-1 I-2 I-3 Irrigation Level (0 to 3 Irrigations)

44 Rain and Irrigation (inches) 2013 Greenville Farm Safflower Study (Rian and Irrigation) 2013 Farm Rain and Irrigation

45 ET (in.) Total Cumulative ET for Irrigation Levels Safflower 2013based on Soil Moisture Measurement (top 5 feet), Precipitation and Irrigation I-3 I-1 I-0 I-2 I-1 I-2

46 Irrigation, Water Use and Yield Location No. Irrigations Irrigation and Precipitation (inches) Soil Water Depletion (inches) ET (inches) Yield (lbs/acre) 1 - E , E , E , W , W , W ,919

47 Summary The number of irrigations made effected the yields with a high significance level. There was the least difference in yield moving from 2 to 3 irrigations. The alternaria leaf spot disease was not a significant factor in the yield. The fungicide treatment resulted in improvement dark ends. In 2013 there was very little rain in June, July, and August while the was maturing. The results could change during a year with higher precipitation.

Presentation at Utah Hay and Forage Symposium February 1, 2013 By L. Niel Allen Irrigation Extension Specialist Utah State University

Presentation at Utah Hay and Forage Symposium February 1, 2013 By L. Niel Allen Irrigation Extension Specialist Utah State University When are Irrigation Strategies for Water-Short Years Important Limited