Page 194 - Nutrient Management Planning Guide

188

Calibrating Manure Application Equipment

Important Terms

Table 4.6.1 Key Terms and Definitions

Term Definition

Calibration

To check, adjust, or determine by observation or testing the rate or volume of manure being applied by a piece of equipment.

Corrected Target Speed

The target application speed of a spreader, that has been corrected to account for differences in density between the manure to be applied versus the manure used during the equipment calibration.

Effective Spreader Width

This is the spreading width that an implement can apply manure at a uniform application rate. An application pass one ‘effective spreader width’ from the last should provide an ideal application overlap that will result in a relatively uniform application. Gross Weight The total weight without deduction for tare or waste.

Net Weight The weight of actual goods (manure), excluding container, wrapper or tarp; also called actual. ‘Reference’ Application Rate

Used to determine an application speed for a targeted application rate based on material with a difference in bulk density. ‘Struck Load’

Is the volume contained in the level-full box. The volumetric capacity of spreaders may be given as a typical “heaped” load condition or as a “struck” load condition. Tare Weight The empty or clean weight of a container, wrapper or tarp.

To be able to apply manure at desired rates it is important to know the performance capabilities of application equipment. While manufacturers provide some basic specifications about the equipment, such as dimensions or capacity, seldom is any information provided about application rates.

Calibrating application equipment provides important information about what rates are possible with a particular piece of equipment, and also the speed (and settings) that can be used to achieve target application rates. There are two calibration techniques:

The load-area method involves estimating the weight •

or volume of manure in a loaded spreader and then determining the area required to spread an entire load (or several loads). The weight-area method involves weighing the •

manure spread over a known area to calculate the rate at which the manure was applied.

A calibration technique should be selected based on the application equipment being used and the type of manure

being applied. If liquid manure is injected, use the load-area method since injected manure cannot be collected. Surface applications of liquid, solid or compost manure should be calibrated using the weight-area method.

Load-Area Calibration

The load-area calibration technique involves measuring the volume of manure in a typical load and the area required to spread the load at constant speed and applicator settings. Dividing volume in the load by the area used to spread the load will yield the application rate for that speed and setting. It may take several loads to cover a known area. In this case the total volume applied will need to be divided by the known area.

This technique requires a note pad, a calculator and flags or stakes to mark off the boundaries of the calibration test area. The distance between markers can be estimated by counting the number of paces between markers and multiplying this by the average distance traveled in a pace.

tip

Water can be used as an alternative source to liquid manure for the initial calibration of manure applicators. This approach is cleaner and will provide a relatively accurate calibration. Some fine tuning of the

equipment may be required when liquid manure is being applied.