managing irrigation water:

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Managing Irrigation water:. Lyndon Kelley MSU Extension / Purdue University Irrigation Management Agent. - find St. Joseph Co. - then hit the Irrigation button. Size , Scale and Make-up. Indiana 313,000 acres. - PowerPoint PPT Presentation


  • Managing Irrigation water:

    Lyndon KelleyMSU Extension / Purdue University Irrigation Management - find St. Joseph Co. - then hit the Irrigation button

  • Size , Scale and Make-upSummarized from 2002 Agricultural CensusMichigan 452,000 acresIndiana 313,000 acres11 Counties = 69.2 % of total11 Counties = 73.8 % of total

  • Crop need15.6 totalNormal rainfall34.6Needed Irrigation5.5

  • Scientific Investigations Report 20055284U.S. Department of the InteriorU.S. Geological SurveyEstimated rainfall recharge

  • Water Quantity NeededIrrigation water replaces the plant water use (removed from soil)Water use is directly correlated to light interception50% light interception results in about 50% of the maximum water useMaximum water use mid-July early August, full light interception, highest temperatures brightest and longest days.

    Evapotranspiration (ET) =fn (net radiation) +fn (temperature) +fn (wind speed) +fn (air humidity)

  • Weighing LysimeterRain and Irrigation increase weightEvapotransporation decrease weight

  • Field beansSoysCornAlfalfa Field beansCornSoysPotatoAlfalfaFrom Minnesota Extension bulletin Irrigation Scheduling, assuming temperature 80-89

    Crop water use


    Weeks after emergence

    Water use (inches)

    Crop Water use curve


    CropWeek after emergence




    field beans0.





  • 1. Irrigation Runoff (comparing irrigation application rate to soil infiltration rate) 0 -30 % loss3. Evaporative loss to the airMinimal loss in our humid area0 6%Estimated 4-6% loss in Nebraska2. Lack of system uniformity 5-35% loss in effectivenessThree factor reducing effective water application

  • Necessary application rate to achieve effective evapo-transportation rates at various application efficiencies

  • Quantity NeededMaximum water use for most crops is .27 - .32 in./day

    3 gal/minute/acre pump capacity = 1/week

    5 gal/minute/acre pump capacity = .25 in./day

    7 gal/minute/acre pump capacity =.33 in./day, 1every 3 days

    500 gal/minute pump can provide 1 every 4 days on 100 acres

  • Think of your soil as a bankIntake rate:Water applied faster than the soil intake rate is lost.Deletion:Plants can pull out only 30 - 60% of the waterWater holding capacity:The soil (bank) can hold only a given volume of water before it allow it to pass lower down.Rooting depth:The plant can only get water to the depth of its roots.Soil type :Heavier soil can hold more water / foot of depth than light soilsWater lost from the bottom of the profile can wash out (leach) water soluble nutrients and pesticides.

  • Calculating Water Holding Capacity

    Soil NameDepthInchesAvailable water holding capacityAverage Available water holding capacityAve. Available water holding capacity ( 24 in.)Ave. Available water holding capacity ( 36 in.)Oshtemo0 - 1414 3535 - 600.10 0.150.12 0.190.06 0.100.1250.1550.0814 x 0.125=1.7510 x 0.155=1.55----------------------- = 3.314 x 0.125= 1.7521 x 0.155= 3.26 1 x 0.08 = 0.08----------------------- = 5.09Spinks0 1010 2626 - 600.08 0.100.08 0.100.04 x 0.09= 0.914 x 0.09= 1.26----------------------- = 2.1610 x 0.09= 0.916 x 0.09= 1.26 8 x 0.06= 0.48----------------------- = 2.64

  • Calculating drought capacityCrop ET. was 0.30 in./day

    Available water capacity of 03.0 in. (AWCI

    Irrigation system can apply 0.20 in./day.

    Started irrigating when the AWC was 1.0 in. down

    3.0 in. (AWC) - 1.0 in. = 2.0 in. available capacity

    2.0 in. available capacity / 0.10 daily deficit = 20 days

    20 days of drought capacity- Not Considering down time

  • Limited water supply Irrigation Management Diversify the crops sharing the water supply between high and low water use.Stager planting date to stager peak water need times.Plant part of irrigated area to a sacrifice crop to neglect during extended drought.

    Start irrigating early to bank water ahead.Stager forage crop cutting dates to avoid simultaneous peak use.

  • 11091320Field #1020 acres20 acres30 acres30 acres

  • Jun 21Jun 22Jun 23Jun 24Jun 25Jun 26757585857575.

    1.53.0-0--0--0--0--0--0-2.001.851.701.521.341.941.790.75corn6-1-08SW 1/436Available

  • Mendon Estimated Evapotranspiration (ET) for July 4, 2008Irrigation scheduling links:Historical E.T. for this siteMSU Scheduler IS 4MichIana Irrigation SchedulerMSU Scheduler ExcelMSU Paper check book system

    Explanation of estimated E.T..Corn 105 day maturity emerging on the listed date in 30 rows.Soybean for grow 3.0 emerging on the listed date.E.T. have been estimate for two days in the future based on future weather forecast.


  • MichIana Irrigation Scheduler: Purdue Agronomy web site Est. From High / Low temp. & date

  • MichIana Irrigation Scheduler out put

  • Irrigation Scheduling Checkbook ChallengesErrors will accumulate over time -Weekly ground truthing needed

    Rainfall variability is more than often considered

    Only "effective rainfall and irrigation should be considered - Only water entering root zone uniformly is "effective

    Corn crop mature in program by calendar, not heat?? Soil Moisture ??

  • Methods to Estimate Soil MoistureFeel an Appearance

    Electrical resistance electrodes on blocks in soil

    Tensiometers measures soil moisture tension

  • NP - Neutron ProbeTDR -Time Domain ReflectometryGS - Gravimetric SamplingAP - Troxler Sentry 200-APAQ - Aquaterr ProbeTM - TensiometerGB - Gypsum BlockWB - Watermark Block

    Qualitative evaluation of soil water monitoring devices.

    A score of 1 is least favorable while a score of 10 is most favorable.

    DEVICENP TDR GS AP AQ TM GB WB INITIAL COST3 1 8 2 7 8 8 8 FIELD SITE SETUP REQUIREMENTS7 3 10 3 10 7 6 6 OBTAINING A ROUTINE READING8 8 1 8 4 10 8 8 INTERPRETATION OF READINGS10 10 10 10 3 5 3 5 ACCURACY10 10 10 8 2 7 2 3 MAINTENANCE9 9 8 9 7 3 9 9 SPECIAL CONSIDERATIONS2 8 5 8 9 7 5 8 COMPOSITE RATING49 49 52 48 42 47 41 47

  • Gravimetric SamplingWet weight Dry weight of a know volume of soil.

    Often refered to as a can test

  • Have you seen yield map patterns that match the irrigation system configuration?

  • Tower 1Tower 3Tower 5Tower 7Tower Joe /Irrigation

    Data Entry

    MSU Extension Irrigation System Evaluation Tool, v1.0

    With farmer permission: please make a copy of this file, remove any information identifying the farmer and email the copy (as an attachment) to The data will be used to develop better and hopefully simpler evaluations tools.

    Farm NameSutfin Farms

    System Uniformity Coefficient =88

    System IdentificationNW Corner 'O' Ave & 42nd near OP Ave 1300ftThe system uniformity coefficient should be 70 or greater

    Deviation from desired application =0.01

    System Settings

    Application rate (in)0.51Wind speed (mph)~ 6

    Percent timer Setting (%)18.5Wind Condition (variable or steady)variable

    Operating Pressue (psi)52

    Length of evaluation area (ft)1430Average Application (cm)1.313

    Average Application (in)0.52

    Catch Can Spacing Distance (ft)10Average catch can (ml)101.09

    70% average catch can (ml)70.76

    number of catch cans used142Evaluation area, full circle (acres)122.82

    catch can openning area (sq cm)76.977

    Diameter of catch can (cm)9.9catch can openning area (sq in)11.767

    catch can numberDistance from center pointcatch volume in mlCommentsWater depth (cm)Water depth (in)% applied of averageDeviation from average (%)Area covered per catch can (acres)Area covered per catch can (% of total)Weighted Deviation

    V bar sub sH&H numorator














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