Formulas and conversions

Sprayer Calibration: Calibration of your spraying equipment is very important. It should be don’t at least every other day of operation to insure application of proper dosages. This is probably the most important step in your whole spraying operation since applying incorrect amounts may do much more damage than good. Each nozzle must be checked so that all nozzles are delivering the same amount of material for a uniform spray pattern.

If a lower rate is desired it may be obtained by increasing speed, reducing the pressure or changing to a smaller nozzle or a combination of the three. The opposite is true if a higher rate is desired.

General Calibration:

I. Method I:

1. Measure out 660 feet.
2. Determine the amount of spray out in traveling this distance at the desired speed.
3. Use this formula: Gallons/acre = gallons used in 660 feet x 66 swath width in feet
4. D. Fill the tank with the desired concentration.

II. Method II:

1. Fill spray tank and spray a specific amount of feet.
2. After spraying refill tank measuring the quantity of material needed for refilling.
3. Use this formula: Gallons/acre = 43560 x gallons delivered swath length(ft.) X swath width (ft.)
4. Fill the tank with the desired concentrate.

III. Method III:

1. Measure 163 feet in the field
2. Time tractor in 163 feet. Make two passes to check accuracy.
3. At edge of field adjust pressure valve until you catch 2 pints (32 ounces) of spray in the same amount of time it took to run the 163 feet. Be sure tractor is at the same throttle setting. You are now applying 20 gallons per acre on a 20 inch nozzle boom spacing.
4. For each inch of nozzle spacing on boom, increase time by 5% or reduce the volume by 5%.

*If you have calibrated your rig and it is putting out 37 gpa, the required dosage is 4 lbs actual/acre. Therefore, for every 37 gallons of carrier (water, oil, etc.) In the spray tank you add 4 lbs of active material.

Quick Conversions:

Temperature Temperature Volume Length Length
C F C F Liters Quarts cm inch cm inch
100 212 15 59 1 1.1 2.5 1 100 39
90 194 10 50 2 2.1 5 2 200 79
80 176 5 41 3 3.2 10 4 feet
70 158 0 32 4 4.2 20 8 300 10
60 140 -5 23 5 5.3 30 12 400 13
50 122 -10 14 6 6.3 40 16 500 16
40 104 -15 5 7 7.4 50 20 1,000 33
35 95 -20 -4 8 8.5 60 24
30 86 -25 -13 9 9.5 70 28
25 77 -30 -22 80 32
20 68 -40 -40 90 36

Table of Conversion Factors:

To Convert From To Multiply By
Cubit feet gallons 7.48
Cubic feet liters 28.3
Gallons milliliters 3785
Grams pounds .0022
Grams/liter parts/million 1000
Liters cubic feet .0353
Milligrams/liter parts/million 1
Milliliters/gallon gallons .0026
Ounces grams 28.35
Parts/million grams/liter .001
Pounds grams 453.59
Pounds/gallons grams/liter 111.83
 1 gram = .035 ounce 1 hectare = 2.5 acres 1 kilogram = 2.2 lbs 1 meter = 39.4 inches 1 quintal = 100 kg = 221 pounds 1 kilometer = .6 mile 1 metric ton = 1000 kg = 2,205 lbs

Conversion Tables (U.S.)

Linear Measure
1 foot = 12 inches
1 yard = 3 feet
1 rod = 5.5 yards = 16.5 feet
1 mile = 160 rods = 1760 yards = 5280 feet

Square Measure
1 square foot (sq. ft.) = 144 square inches (sq. inch.)
1 square yard (sq. yd) = 9 sq. feet
1 square rod (sq rd) = 272.25 sq. ft. – 30.25 sq. yds.
1 acre = 43560 sq. ft. = 4840 sq. yd. = 169 sq. rd.
1 sq. mile = 640 acres

Cubic Measure
1 cubic foot (cu. ft.) = 1728 cubic inches (cu. in.)
1 cubic yard = 27 cubic feet

Liquid Capacity Measure
1 tablespoon = 3 teaspoons
1 fluid ounce = 2 tablespoons
1 cup = 8 fluid ounces
1 pint = 2 cups = 16 fluid ounces
1 quart = 2 pints = 32 fluid ounces
1 gallon = 4 quarts = 8 pints = 128 fluid ounces

Weight Measure
1 pound = 16 ounces
1 hundred weight (cwt) = 100 pounds
1 ton = 20 cwt = 2000 pounds

Rates of Application
1 ounce/sq ft = 2722.5 lbs/acre
1 ounce/sq yd = 302.5 lbs/acre
1 ounce/100 sq ft = 27.2 lbs/acre
1 pound/100 sq ft = 435.6 lbs/acre
1 pound/1000 sq ft = 43.6 lbs/acre
1 gallon/acre = 1/3 ounce/1000 square feet
5 gallons/acre = 1 pint/100 sq ft
100 gallons/acre = 2.3 gallons/1000 sq ft = 1 quart/100 sq ft
100 lbs/acre = 2.5 pounds/1000 sq ft

Important Facts
Volume of sphere – diameter cubed x .5236
Diameter = circumference x .31831
Area of a circle = dia squared x .7854
Area of ellipse = prod. of both dia x .7854
Volume of cone = area of base x 1/3 height
1 cubic foot water = 7.5 gallons = 62.5 pounds
Pressure in psi = ht. (ft.) X .434
1 acre = 209 feet square

Measure of Length: (Linear Measure)
4 inches = 1 hand
9 inches = 1 span
12 inches = 1 foot
3 feet = 1 yard
6 feet = 1 fathom
5.5 yards = 16.5 feet = 1 rod
40 poles = 1 furlog
8 furlogs = 1 mile
5,280 feet = 1,760 yards = 320 rods = 1 mile
3 miles = 1 league

Measure of Surface: (area)
144 Square inches = 1 square foot
9 square feet = 1 square yard
30.25 square yards = 1 square rod
160 square rods = 1 acre
43,560 square feet = 1 acre
640 square acres = 1 square mile
36 square miles = 1 township

Liquid Measure
2 cups = 1 pint
16 fluid ounces = 1 pint
2 pints = 1 quart
4 quarts = 1 gallon
1 gallon = 231 cubic inches
1 cubic foot = 7.48 gallons