4.5 Rate of Output (GPM)

The gallons of spray desired per acre and the time required to spray an acre determine the rate of output for which the sprayer must be nozzled. Since volume of spray needed per acre varies with tree size, the most common row-spacing for the tree size to be sprayed should be used in calibrating the sprayer. The gallons of dilute spray required for various row-spacing and tree-size combinations are indicated in Table 4.4.1. Gallons of concentrate spray required is determined by dividing dilute gallonage by the concentration desired. The rate of output by the sprayer is calculated by dividing the gallons of concentrate spray by the time required to spray 1 acre, Table 4.5.1.

Table 4.5.1. Approximate time required to spray 1 acre of orchard (two-sided sprayer operation, spraying both sides of trees).

Distance between Rows (feet)	Linear feet of Row/ acre¹	Travel speed (mph)
		1	1.5	2	2.5	3
		minutes per acre²
40	1089	12.4	8.2	6.2	5.0	4.1
30	1452	16.5	11.0	8.2	6.6	5.5
25	1742	19.8	12.4	9.9	7.9	6.6
22	1980	22.5	15.0	11.2	9.0	7.5
20	2178	24.8	16.5	12.4	9.9	8.3
18	2420	27.5	18.3	13.8	11.0	9.2
16	2723	30.9	20.6	15.5	12.4	10.3
14	3112	35.4	23.6	17.7	14.1	11.8
¹Linear feet of row per acre = 43,560 divided by distance between rows. ²Minutes per acre = linear feet of row per acre divided by speed in feet per minute. Speed in feet per minute = mph x 88.

4.5.1 Example for Calibrating Rate of Output: Rows 30 feet apart, trees 20 feet wide x 15 feet high. A 4X concentrate application is to be made at a speed of 2.5 miles per hour.

Table 4.4.1 indicates 300 gallons of dilute spray required per acre.
300 (gal) divided by 4(X) = 75 gallons of 4X concentrate per acre required.
Table 4.5.1 indicates 6.6 minutes required to spray 1 acre of 30-foot rows at a speed of 2.5 mph.
Total sprayer output for 2-sided operation = 75 (gal/acre) divided by 6.6 (min/acre) = 11.36 gallons per minute.
Output required per side = 11.36 divided by 2 = 5.68 gallons per minute per side.
Rate of output = 5.68 gal/min/side.