Page 157 - Nutrient Management Planning Guide

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Chapter 4.2

tip

For severely weathered piles, it is best to sample during application rather than trying to obtain a representative sample. The weathered exterior of uncovered manure piles does not accurately represent the majority of the material in the pile. Rainfall generally moves water-soluble nutrients down into the pile while volatile compounds generally gas-off the weathered exterior.

It is recommended that 15 to 20 samples be collected to form each composite sample. Sub-samples from each composite sample are taken and combined to form a single composite sub-sample, which is sent for analysis. Alternatively, each of the sub-samples can be sent for separate analysis. This may allow more site-specific nutrient management planning, particularly if the field that received manure represented by a specific composite sample (particular day, source or stage of the application process) was recorded.

There are two strategies for sampling manure during application: during loading of application equipment, or as manure is being applied. In either case, the following equipment is required: 20 L (5 gal) plastic pail or larger plastic garbage can • wheelbarrow • shovel, pitchfork or solid manure-sampling probe •

(Figure 4.2.4) several tarps, plastic sheets or a piece of plywood • one or more large plastic freezer bags •

Sampling Solid Manure During Loading

Collect several grab samples from selected loads 1.

using a shovel, pitchfork or sampling probe. These grab samples will count as a single sample for that load. Avoid large chunks of bedding.

Place grab samples in the wheelbarrow. If the 2.

amount of manure collected exceeds the capacity of the wheelbarrow, each time the wheelbarrow is two-thirds full, thoroughly mix the material and one or two shovels full to the pail or suitable mixing area (tarp, plywood or concrete pad). Collect samples from 15 to 20 wheelbarrow loads if the material is relative consistent and representative of the manure applied for a particular day, source, or stage of the application process. For more variable material, a greater number of loads may need to be sampled or more composite samples may need to be collected.

To sub-sample, begin by thoroughly mixing 3.

material collected in the pail or from the mixing area with a pitchfork or shovel. Break up any large clumps.

Divide the well-mixed manure into four portions 4.

and then discard two of the four portions. Combine the remaining two portions and mix.

Repeat step 4 until approximately 0.5 kg (1 lb) 5.

of material remains. This will be the composite sub-sample for analysis.

Place the composite sub-sample in a plastic bag 6.

filled two-thirds full to allow for gas expansion.

Squeeze excess air out of the bag, seal and 7.

double bag to prevent excessive odour and leaking.

Label bag with date, time, farm name, manure 8.

type, and any other information requested by the testing facility.

Keep bagged composite sub-samples cool and 9.

ship immediately to the lab. Store samples that cannot be delivered immediately in a freezer.

Repeat steps 1 to 3 until all manure has been 10. applied.