Page 197 - Nutrient Management Planning Guide

191

Chapter 4.6

Calculate Application Rate 4.

To calculate the application rate, multiply the estimated volume of manure applied by the number of loads applied and then divide by the area covered by the test loads:

Application Rate = (Volume per Spreader Load × Number of Loads) ÷ Calibration Test Area

Calculating Application Rate

The volume of manure per spreader load is 62,550 L and the calibration test area covered by three loads of manure applied at a given speed was 1.89 ha. The application rate is calculated as:

Application Rate (L/ha) = (volume (L/load) × number of loads) ÷ calibration test area = (62,550 L/load × 3 loads) ÷ 1.89 ha = 187,650 L ÷ 1.89 ha

= 99,286 L/ha is the application rate

Calculating Application Rate for a Dragline System

Dragline application systems are slightly easier to calibrate since application rate can be determined using the flow rate, the width of application and ground speed of the applicator. The application rate in a dragline system is calculated as:

Application Rate (L/ha) =

[Flow rate (L/min) × 60 min/h × 10,000 m 2 /ha] ÷ [Speed (km/h) × 1000 m/km × Width of application (m)]

Or,

Application Rate (gal/ac) =

[Flow rate (gal/min) × 60 min/h × 43,560 ft 2 /ac] ÷ [Speed (mi/h) × 5280 ft/mi × Width of application (ft)]

The conversion factors in the top and bottom lines of each equation are necessary so that the units in the calculation are compatible. The desired application rate can be achieved through altering any of the factors in the equation. Note that this strategy also works for other liquid application systems where flow rate can be manipulated.