Extension Circular 58-704: This  is about how to efficiently irrigate your crops

Decker, John F.

Fischbach, Paul E.

Mulliner, H. R.

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnHistorical Materials from University of Nebraska-Lincoln Extension Extension1958EC58-704 Efficient IrrigationPaul E. FischbachH. R. MullinerJohn F. DeckerFollow this and additional works at: http://digitalcommons.unl.edu/extensionhistThis Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted forinclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University ofNebraska - Lincoln.Fischbach, Paul E.; Mulliner, H. R.; and Decker, John F., "EC58-704 Efficient Irrigation" (1958). Historical Materials from University ofNebraska-Lincoln Extension. 3406.http://digitalcommons.unl.edu/extensionhist/3406.E. C. 58-704 ;:; Paul E. Fischbac , ~- ~~ ulliner, John F. Decker Efficient irrigation is obtained by filling t he effective root zone of the c~op each irrigation and by minimizing run-off. Since dry soils will take in water much faster than the basic intake rate, water should be applied in larger volume at the start of irrigation with the fur-row stream reduced aft er furrows have been wetted. Rule to follow: Get stream of water through each fur-row in one-fourth the total time it takes to irrigate, then cut back the furrow stream. Siphon tubes or gate opening should be selected on the basic furrow stream size. Two or more tubes or twice the final gate opening per furrow may be used for the initial application. EXTENSION SERVICE UNIVERSITY OF NEBRASKA COLLEGE OF AGRICUlTURE AND U.S. DEPARTMENT OF AGRICUlTURE COOPERATING W. V. lAMBERT, DIRECTOR Slope, considered of gates. intake rate and length of run must all be in determining siphon tube size and size The number 10 divided by slope gives the maximum non-erosive stream size per furrow. (Siphon tube or gate should discharge only l/2 or 1/3 of this amount). Examples 2.o{o slope - 5 gpm .5r{o slope - 20 gpn l.o{o slope - 10 gp}IL .4r{o slope - 25 gpn .9{o slope - ll gpm .3r{o slope - 33 gpm .7rfo slope - 14 gpm .';!fa slope - 50 gpm Basic intake rate varies between soils and for the same field at different irrigations. The following data may be used as guides: Soil Texture GPM/1001 Acre Inches/Hour Inches Water of Row 40" Row 38" Row HeldLfoot Loamy sand 2.4 .70 ·73 ·73 - 1.00 Sandy loam. 1.9 ·55 .58 1.25 - 1.50 Very fine sandy loam 1.7 .49 .52 1.50 - 1.75 Silt loam l.l .32 .34 1.75 - 2.25 Silty clay loam 0.7 .20 .21 2.00 - 2.25 Clay loam 0.5 .14 .15 2.00 - 2.25 Clays 0.3 .08 .09 1.80 - 2.00 Some clayey soils may have intake rates as high as sandy loam.s . Water discharged per siphon tube: Inches Head Tube Size 2 3 4 5 6 inches -Ga.llo:rlS"" per minute 3/ 4" 2 3 5 6 7 l" 4 5 7 8 9 l-1/8" 6 7 8 10 ll 1-1/4" 8 10 12 13 15 1-1/ 211 13 16 18 21 24 211 21 27 32 36 40 In field practice use of multi-ple tubes for wetting furrows is best accomplished by applying initial streams to alternate rows - run until furrow streams reach end of rows Then change all tubes to alter-nate dry rows. When second set of rows have been wetted, one tube is then changed to previously wetted furrows and the double set is allowed to run 4 times as long as the wetting period. The same practice may be followed using gated pipe by varying gate openings. Larger initial streams may be limited by gate openings. The following examples show how basic data is used to de~ermine siphon tube size) length of run) and time to apply water for a full irrigation in 40 inch rows: Siphon tube size: Per cent slope Non-erosive stream Cut-back stream Siphon tube head (" water) Siphon tube size Length of Runs* Basic intake-gpm/ 100' Cut-back stream Intake/100' Length of run Soil Sandy loam 0.3 33 gpm 16 gpm 3 ~-16 gpm Soil Sandy loam 1.9 16 = 8 1.9 800' Texture Silt loam 0.4 25 gpm 12 gpm 4 .~.-f;:-"-12gpm Texture Silt loam 1.1 12 = ll 1.1 1100' * Rows will need to be shortened 5 to 10 per cent for cutback stream to reach end of furrow. Time to apply water: Water capacity/ ' profile Water capacity- 5' level Water to apply @50% level Water intake rate Hours to apply water Hours-initial stream Hours -cut-back stream Soil Texture Sandy loam Silt loam 1.37" 6.85" 3.42" .55" / hr. 6.2 hours 1 hr. 33 min. 6.0 hours 2.0" 10.0" 5.0" .32" / hr. 15.5 hours 3hrs.55min. 15.0 hours Note -- For farms of variable soils or variable lengths of run) more than one siphon tube size should be used. 

EC58-704  Efficient Irrigation

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University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Historical Materials from University of Nebraska-
Lincoln Extension Extension
1958
EC58-704 Efficient Irrigation
Paul E. Fischbach
H. R. Mulliner
John F. Decker
Follow this and additional works at: http://digitalcommons.unl.edu/extensionhist
This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for
inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of
Nebraska - Lincoln.
Fischbach, Paul E.; Mulliner, H. R.; and Decker, John F., "EC58-704 Efficient Irrigation" (1958). Historical Materials from University of
Nebraska-Lincoln Extension. 3406.
http://digitalcommons.unl.edu/extensionhist/3406
.E. C. 58-704 
;:; 
Paul E. Fischbac , ~- ~~ ulliner, John F. Decker 
Efficient irrigation is obtained by filling t he 
effective root zone of the c~op each irrigation and by 
minimizing run-off. 
Since dry soils will take in water much faster 
than the basic intake rate, water should be applied in 
larger volume at the start of irrigation with the fur-
row stream reduced aft er furrows have been wetted. 
Rule to follow: Get stream of water through each fur-
row in one-fourth the total time it takes to irrigate, 
then cut back the furrow stream. 
Siphon tubes or gate opening should be selected 
on the basic furrow stream size. Two or more tubes or 
twice the final gate opening per furrow may be used 
for the initial application. 
EXTENSION SERVICE 
UNIVERSITY OF NEBRASKA COLLEGE OF AGRICUlTURE 
AND U.S. DEPARTMENT OF AGRICUlTURE 
COOPERATING 
W. V. lAMBERT, DIRECTOR 
Slope, 
considered 
of gates. 
intake rate and length of run must all be 
in determining siphon tube size and size 
The number 10 divided by slope gives the maximum 
non-erosive stream size per furrow. (Siphon tube or 
gate should discharge only l/2 or 1/3 of this amount). 
Examples 
2.o{o slope - 5 gpm .5r{o slope - 20 gpn 
l.o{o slope - 10 gp}IL .4r{o slope - 25 gpn 
.9{o slope - ll gpm .3r{o slope - 33 gpm 
.7rfo slope - 14 gpm .';!fa slope - 50 gpm 
Basic intake rate varies between soils and for 
the same field at different irrigations. The following 
data may be used as guides: 
Soil Texture GPM/1001 Acre Inches/Hour Inches Water 
of Row 40" Row 38" Row HeldLfoot 
Loamy sand 2.4 .70 ·73 ·73 - 1.00 
Sandy loam. 1.9 ·55 .58 1.25 - 1.50 
Very fine 
sandy loam 1.7 .49 .52 1.50 - 1.75 
Silt loam l.l .32 .34 1.75 - 2.25 
Silty clay loam 0.7 .20 .21 2.00 - 2.25 
Clay loam 0.5 .14 .15 2.00 - 2.25 
Clays 0.3 .08 .09 1.80 - 2.00 
Some clayey soils may have intake rates as high 
as sandy loam.s . 
Water discharged per siphon tube: 
Inches Head 
Tube Size 2 3 4 5 6 
inches -Ga.llo:rlS"" per minute 
3/ 4" 2 3 5 6 7 
l" 4 5 7 8 9 
l-1/8" 6 7 8 10 ll 
1-1/4" 8 10 12 13 15 
1-1/ 211 13 16 18 21 24 
211 21 27 32 36 40 
In field practice use of multi-
ple tubes for wetting furrows is 
best accomplished by applying 
initial streams to alternate 
rows - run until furrow streams 
reach end of rows 
Then change all tubes to alter-
nate dry rows. 
When second set of rows have been 
wetted, one tube is then changed 
to previously wetted furrows and 
the double set is allowed to run 
4 times as long as the wetting 
period. 
The same practice may be followed using gated pipe 
by varying gate openings. Larger initial streams may 
be limited by gate openings. 
The following examples show how basic data is used 
to de~ermine siphon tube size) length of run) and time 
to apply water for a full irrigation in 40 inch rows: 
Siphon tube size: 
Per cent slope 
Non-erosive stream 
Cut-back stream 
Siphon tube head (" water) 
Siphon tube size 
Length of Runs* 
Basic intake-gpm/ 100' 
Cut-back stream 
Intake/100' 
Length of run 
Soil 
Sandy loam 
0.3 
33 gpm 
16 gpm 
3 
~-16 gpm 
Soil 
Sandy loam 
1.9 
16 = 8 
1.9 
800' 
Texture 
Silt loam 
0.4 
25 gpm 
12 gpm 
4 
.~.-f;:-"-12gpm 
Texture 
Silt loam 
1.1 
12 = ll 
1.1 
1100' 
* Rows will need to be shortened 5 to 10 per cent 
for cutback stream to reach end of furrow. 
Time to apply water: 
Water capacity/ ' profile 
Water capacity- 5' level 
Water to apply @50% level 
Water intake rate 
Hours to apply water 
Hours-initial stream 
Hours -cut-back stream 
Soil Texture 
Sandy loam Silt loam 
1.37" 
6.85" 
3.42" 
.55" / hr. 
6.2 hours 
1 hr. 33 min. 
6.0 hours 
2.0" 
10.0" 
5.0" 
.32" / hr. 
15.5 hours 
3hrs.55min. 
15.0 hours 
Note -- For farms of variable soils or variable lengths 
of run) more than one siphon tube size should 
be used. 


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EC58-704 Efficient Irrigation

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