Page 203 - Nutrient Management Planning Guide

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Chapter 4.6

Draw a straight line to connect the data points 3.

corresponding to the application rates at low and high speeds. This line is the calibration curve for that particular setting. Repeat steps 1 through 3 for each available setting 4.

for the spreader.

Figure 4.6.4 Sample Calibration Graph for a Manure Spreader

Once lines have been graphed for each of the settings, they can be referred to in the future when using this equipment. For each target application rate, identified along the vertical axis of the graph, a corresponding equipment setting and speed can be selected (Figure 4.6.5). Building a calibration graph is time consuming, but in the long run the overall benefit of the calibration graph is that it will save time. The calibration graph can be quickly referenced so that manure application rates, equipment settings and travel speeds can be adjusted to meet a variety of field conditions.

Figure 4.6.5 Identifying the Travel Speed from a Calibration Line.

Adjusting for Differences in Manure Density

Basically, if lower density manure is being applied, a higher travel speed is required to apply an equivalent amount of material that has a higher density. A calibration graph for a solid manure spreader, calibrated for a specific density of material can be used to determine the correct traveling speed for application of material with a different density.

If the density of the manure changes, the actual application rate can be derived from the vertical axis of the calibration graph by using the following equation.

‘Reference’ Application Rate

= Desired Application Rate (for the un-calibrated manure to be applied) x (Calibration Manure Density ÷ Density of Manure to be Applied)

tip

Completing this process can be very beneficial to custom manure applicators who are dealing with a variety of different types and densities of manure.