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Calibrating Traveling Big Gun Sprinklers for Manure Applications

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Importance of Calibration •  Calibration •  Traveling Gun Layout •  Wastewater Applied by Traveling Big Gun Sprayers

Importance of Calibration

You can avoid the potential adverse effect on ground and surface water caused by over fertilization by applying only the amount of waste and wastewater necessary to maintain soil fertility for crop production.

The calibration of liquid manure spreading equipment is important because it lets you know the amount of waste and wastewater you are applying to an area.

The calibration rate and the nutrient concentration level of the

liquid manure lets you know the amount of plant nutrients you are applying. Then, you can adjust your fertilization rate to avoid overfertilization.

Calibration

The volume of wastewater applied by a traveling gun depends on the flow rate, lane spacing, travel distance and travel time. The necessary steps to calibrate a traveling big gun sprinkler are given in the example below.

1) Determine the volume of wastewater applied in inches (in) from the manufacturer's literature or Table 1. Note that Table 1 includes a formula to be used as needed

Example: From Table 1:   200 G P M flow rate,   150    foot lane spacing, and a   2.0   foot/minimum travel speed should apply   1.1   inches of wastewater.

Your Numbers:   a           G P M flow rate,          foot lane spacing, and a         foot/minimum travel speed should apply         inches of wastewater.

2) Determine the wastewater application rate in gallons per acre (gal/ac) by multiplying the inches of wastewater applied from Step 1 by 27,154 gal/ac. a

Example:  1.1  inches x 27,154 gal/ac-in =    30,000   gal/ac 

Your Numbers:         inches x 27,154 gal/ac-in =             gal/ac

3) The pounds of N applied per acre (lb N/ac) is calculated by multiplying the wastewater application rate from Step 2 by the pounds of N per thousand gallons of wastewater1
and then dividing by 1000.

Example:   30,000 gal/ac x   5   lb N/1000 gal ÷ 1000 =  150  lb N/ac

Your Numbers:         gal/ac x       lb N/1000 gal ÷ 1000 =       lb N/ac

OR
1) Determine the volume of wastewater (gal/ac) to apply divide the desired number of pounds of N per acre (lb N/ac) by the number of pounds of N in a thousand gallons of wastewater1
(lb N/1000 gal) and then multiply by 1000.

Example:  150  lb N/ac ÷   5    lb N/1000 gal x 1000 =   30,000   gal/ac

Your Numbers:         lb N/ac ÷        lb N/1000 gal x 1000 =            gal/ac

2) Convert the volume of wastewater required (gal/ac) from Step 1 to inches by dividing by the conversion factors 27,154 gal/ac-in.

Example:  30,000   gal/ac ÷ 27,154 gal/ac-in =   1.1   inches.

Your Numbers:             gal/ac ÷ 27,154 gal/ac-in =         inches.

3) Use the inches of wastewater from Step 2 and Table 1 or your manufacturer's literature to determine the desired flow rate (G P M), lane spacing (ft), and travel speed (ft/min). 

Example: From Table 1:    200  G P M flow rate,   150    foot lane spacing, and a   2.0   foot/minimum travel speed should apply   1.1   inches of wastewater.

Your Numbers:   a           G P M flow rate,          foot lane spacing, and a         foot/minimum travel speed should apply         inches of wastewater.
1Refer to the University of Arkansas Extension publications Liquid Animal Waste Sampling (F S A 3006) and Understanding Your Animal Waste Nutrient Analysis (F S A 3008) for information on having your liquid manure analyzed and interpreting the analysis.

Figure 1 - Traveling Gun Layout

 

 

Table 1. Wastewater Applied by traveling Big Gun Sprayers
Sprinkler Flow Rate (GPM) Travel Lane Spacing (ft)* Travel Speed (feet per minute)
0.4 0.5 1 2 4 6 8 10
Wastewater Applied (inches)

100

150

2.7

2.1

1.1

0.5

0.3

0.2

0.1

0.1

200

2

1.6

0.8

0.4

0.2

0.1

0.1

0.1

250

1.6

1.3

0.6

0.3

0.2

0.1

0.1

0.1

300

1.3

1.1

0.5

0.3

0.1

0.1

0.1

0.1

200

150

5.4

4.3

2.1

1.1

0.5

0.4

0.3

0.2

200

4

3.2

1.6

0.8

0.4

0.3

0.2

0.2

250

3.2

2.6

1.3

0.6

0.3

0.2

0.2

0.1

300

2.7

2.1

1.1

0.5

0.3

0.2

0.1

0.1

300

200

6

4.8

2.4

1.2

0.6

0.4

0.3

0.2

250

4.8

3.9

1.9

1

0.5

0.3

0.2

0.2

300

4

3.2

1.6

0.8

0.4

0.3

0.2

0.2

350

3.4

2.8

1.4

0.7

0.3

0.2

0.2

0.1

400

200

8

6.4

3.2

1.6

0.8

0.5

0.4

0.3

250

6.4

5.1

2.6

1.3

0.6

0.4

0.3

0.3

300

5.4

4.3

2.1

1.1

0.5

0.4

0.3

0.2

350

4.6

3.7

1.8

0.9

0.5

0.3

0.2

0.2

500

250

8

6.4

3.2

1.6

0.8

0.5

0.4

0.3

300

6.7

5.4

2.7

1.3

0.7

0.4

0.3

0.3

350

5.7

4.6

2.3

1.1

0.6

0.4

0.3

0.2

400

5

4

2

1

0.5

0.3

0.3

0.2

600

250

9.6

7.7

3.9

1.9

1

0.6

0.5

0.4

300

8

6.4

3.2

1.6

0.8

0.5

0.4

0.3

350

6.9

5.5

2.8

1.4

0.7

0.5

0.3

0.3

400

6

4.8

2.4

1.2

0.6

0.4

0.3

0.2

700

300

9.4

7.5

3.7

1.9

0.9

0.6

0.5

0.4

350

8

6.4

3.2

1.6

0.8

0.5

0.4

0.3

400

7

5.6

2.8

1.4

0.7

0.5

0.4

0.3

450

6.2

5

2.5

1.2

0.6

0.4

0.3

0.2
*The Travel Lane Spacing should be approximately 70% of the sprinkler's coverage diameter. The coverage diameter can be determined from the manufacturer's literature or by measurement. Refer to Figure 1 for a diagram of a traveling gun layout.

NOTE: If your exact numbers are not in the table, use the formula below to calculate the application rate. The mathematical operations should be done in order from left to right.

Wastewater Applied (in) = 1.6 x Sprinkler Flow Rate (G P M) - Lane Spacing (ft) - Speed (ft/min)

 

Author:

Karl VanDevender - Extension Agricultural Engineer
Phil Tacker - Extension Agricultural Engineer
John Langston, Extension Agricultural Engineer

DR. KARL VANDEVENDER, PHIL TACKER and JOHN LANGSTON are Extension agricultural engineers. All are with the Cooperative Extension Service, University of Arkansas, Little Rock.

ANGELA RIECK, former Extension assistant specialist - waste management, was a contributing author of this publication. This publication was funded in part by the Cooperative Extension Service, University of Arkansas, the Environmental Protection Agency, and the Arkansas Soil and Water Conservation Commission.

FSA1022-PD-4-02R

© 2006
University of Arkansas
Division of Agriculture
All rights reserved.
Last Date Modified 08/27/2008
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