Drip Irrigation Research in Arkansas by ewghwehws

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									Drip Irrigation Research
      in Arkansas

          Earl Vories
        University of Arkansas
 Northeast Research & Extension Center
            Keiser, Arkansas
Center Pivot and Furrow Irrigation
   Common in the Mid-South
Leachville                      Blytheville
                                              Satellite
                                              Image of
             Manila                           NE Ark.
                                              Aug., 99




                      Osceola
Drip Irrigation Getting Interest
• Earlier use in arid areas (AZ, west TX,
  Israel).
• Efficient use of limited water.
• Allows injection of fertilizers/other
  products in root zone.
• More recently being investigated in
  humid areas (southeast, mid-south).
  Current research efforts in
Arkansas using precise water
   control possible with drip
    irrigation to investigate
 irrigation scheduling, rather
than investigating the optimal
   drip irrigated production
             system.
                              Change in Water Use With Crop Age
 Typical* Water Use (in.)   0.4                                            Last Ef f ect ive Flower


                                  Plant ing
                                              Cotton                       (80 DAP - mid-August )


                            0.3
                                                                  First Flower
                                                 First Square
                                                                  (57-63 DAP)
                                                 (32-38 DAP)

                            0.2
                                                                                         First Open Boll
                                    Emergence
                                                                                          (>100 DAP)
                                    (4-10 DAP)

                            0.1

                             0
                             27-Apr           25-May            22-Jun           20-Jul               17-Aug
* based on Keiser                                Date (for May 1 planting)
30-yr mean Tmax
Computerized Irrigation Scheduler
  Distributed by University of Arkansas
     Cooperative Extension Service
             (www.uaex.edu)
Computerized Irrigation Scheduler
Computerized Irrigation Scheduler
                           Reference Evapotranspiration (Etr)

                         0.4
est. 30-yr ETr (63-92)


                               Keiser
                         0.3

                         0.2

                         0.1

                         0.0
                          10-Apr   29-May   17-Jul   04-Sep   23-Oct
                              Crop Coefficient Function - Cotton
                            1.2                                             Last Effective Flower
Crop Coefficient (ET/ETr)
                                                                            (80 DAP - mid-August)
                                               Cotton
                             1                                      First Flower
                                                                    (57-63 DAP)
                            0.8                      First Square
                                    Planting         (32-38 DAP)
                                                                                           First Open Boll
                            0.6         Emergence                                          (> 100 DAP)
                                        (4-10 DAP)
                            0.4
                            0.2

                             0
                                  -10           11        32           53             74             95
                                                Crop Age (days after emergence)
                              Crop Coefficient Function - Corn
Crop Coefficient (ET/ETr)
                            1.1
                                      Corn
                            0.9

                            0.7

                            0.5

                            0.3

                            0.1
                                  0    20    40   60   80   100    120 140
                                            Days After Emergence
As you would expect, many
differences between the drip
   irrigation systems on a
production-field scale and a
 small-plot research scale.
Field Scale
              System Controls

                   Small Plot
                 Injector Pumps
for Water Conditioners (generally required for groundwater)
            Fertilizers, Soil Conditioners, etc.
Filter Bank for Groundwater
          Field Scale
RPZ Valve and Screen for Municipal Water
   Small Plot
Solenoids for Controlling Water

                       Small Plot
  Field Scale
Lateral Lines Feeding Individual Drip Lines
                                 Small Plot


     Field Scale
Much of 2001 growing season
 spent installing and testing
irrigation/control/monitoring
 systems, probably reducing
     potential responses.
      Estimated Soil Water Deficits - Corn
            7

            6
                                                  No Irr.
            5
SWD (in.)




                           Irrigation System
            4              Began Operation
                                                            75% ET
            3
            2

            1                                               125% ET
            0
             4/29   5/13     5/27   6/10       6/24   7/8    7/22     8/5
                Corn Yields (bu/acre)
200                                Yields not significantly
180                                   affected by water
                                         treatments.
160
140
120
                                        T 2160 BT
100
                                        P 34B24 BT
 80
                                        DK C69-70 BT
 60
 40
 20
  0
      No Irr.     75% ET 125% ET
 Later season allowed more
observations in cotton study,
 more treatment differences
          observed.
    Estimated Soil Water Deficits - Cotton

            7
            6
                                        No Irr.         60% ET
            5
SWD (in.)




                    Irrigation System
            4
                    Began Operation
            3
            2
                                                         100% ET
            1
            0
             5/10   5/31     6/21       7/12      8/2    8/23    9/13
Watermark sensor
           Output from Watermark Sensors - Cotton

                 3.5
                                                    Final Irrigation
                 3.0
Tension (bars)




                 2.5
                                No Irr.
                 2.0
                 1.5
                                          60% ET
                 1.0
                 0.5
                                          100% ET
                 0.0
                    7/22 7/30 8/7 8/15 8/23 8/31 9/8 9/16 9/24
          Crop Response to Water




                               No Irrigation
100% ET
Physiological Cutout (NAWF=5, DAP)
86
84
82
80
78
                                  SG 747
76
                                  PSC 355
74                                NuCotn 33B
72
70
68
66
     No Irr.   60% ET   100% ET
        Mean Maturity (DAP)
145

140

135
                                   SG 747
                                   PSC 355
130
                                   NuCotn 33B

125

120
      No Irr.   60% ET   100% ET
         Seedcotton Yields (lb/acre)
3500                                      Yields not
                                    significantly affected
                                    by water treatments.
3000
2500
2000                                    SG 747
1500                                    PSC 355
                                        NuCotn 33B
1000
500
  0
       No Irr.   60% ET   100% ET
       Conclusions from 2001
• System/equipment functioning well.
• Installation of drip tubing (subsoiling every
  row) in spring, as well as delays in planting
  and irrigating due to installation probably
  affected responses in initial season.
• Drip irrigation system appears to provide
  desired water control for studying irrigation
  scheduling.
     Acknowledgment

 Research supported by Arkansas
corn and cotton producers through
       checkoff programs.

								
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