Calibrating the sprayer--second method

1. Fill sprayer completely or to known level with water only.
2. Spray a known area such as 1/4 or 1/2 acre. Area sprayed can be determined by counting trees sprayed (two half trees equals one tree) and multiplying by area occupied by each tree (row spacing x in-row spacing). One acre equals 43,560 square feet.
3. Return to filling site and try to position sprayer and tractor in same position as in (1) above.
4. Carefully measure amount of water needed to refill to previous level.
5. Convert to an acreage rate. For example, if enough trees are sprayed to cover 1/4 acre (10,890 sq ft) and 12 gallons are required to refill the tank, the application rate is 48 gallons per acre.

Example: We want to spray a block of apples planted 14 feet apart in 22-foot-row spacing (14 ft x 22 ft). Each tree (or two half trees) occupies 308 (14 x 22) square feet of area. Therefore, there are 140 (43,560 sq ft/A ÷ 308 sq ft) trees per acre, or 35 trees in 1/4 acre. We spray 35 trees at desired speed and pressure
and return to filling spot.

Carefully measuring the amount of water required to refill to previous level, we find that we sprayed 12 gallons. The application rate per acre is 48 (12 x 4) gallons per acre. Adjust pressure, driving speed, nozzle flow, or any combination to change rate.