T-4-114 - Sampling Procedures for Fertilizers

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September 1997


The Fertilizers Regulations specify basic conditions that must be fulfilled to ensure that a sample of fertilizer fairly represents the lot of fertilizer from which it is taken. These conditions are:

  1. sample be of sufficient size for analysis;
  2. in case of lots or shipments of 10 bags or less, a sample shall consist of approximately equal portions drawn from each bag in the lot;
  3. in the case of lots or shipments of 11 bags or more, a sample shall consist of approximately equal portions drawn from each of any 10 bags in the lot or shipment; and
  4. in the case of bulk shipments, a sample shall consist of approximately equal portions drawn from 10 different sections of the bulk

The following procedures and information concerning fertilizer sampling and reporting are approved by the Director for the purposes of sections 22 and 23 of the Regulations under the Fertilizers Act.

Part A – Mechanics of Sampling

1. Dry Products – Bagged or Packaged

Bags 11 kg and over – use a single tube open trier with a diameter of at least 2.0 cm and in the length range 65-90 cm; for example, "Ontario trier". The trier is to be used in the horizontal plane, inserted to it's full effective length diagonally through the container and rotated and withdrawn so that it will remove fertilizer from each part through which the trier travelled. The trier is to be inserted with the opening down and withdrawn with the opening up. Sample the number of bags specified in Regulation 22(2)(a) and (b).

Bags under 11 kg – Since it is impractical to try to sample bags under 11 kg, with a trier, take one bag as a sample of the lot. However, the official status of this sample must be limited to the one bag. If it is found deficient, the lot should then be sampled by the method as laid out for bags 11 kg and over.

Figure 1(a)

Single Tube Trier. Must be equal to or greater than 25 inches long.

Single Tube Open Trier Sampling Tool

2. Dry Products – In Bulk

a) Static Lot Sampling

Use the "Missouri D Tube" trier (length 135 cm, 53.15 in).
The trier is to be used in the vertical plane, inserted in the open position to its full effective length where possible, closed and withdrawn. Secure at least 10 cores from the bin or pile according to the following sampling patterns. The 65-90 cm trier shall not be used for bulk lots.

Figure 1

Bag Sampling Technique

Bagged Products Sampling Technique

Figure 2

Missouri D Tube. Length 52 inches, Outer Diameter 1.25 inches, one slot 45 inches long

Missouri "D" Tube

Figure 3(a)

Sample pattern for Ridge Pile.

Example Pattern for Ridge Pile

Figure 3(b)

Sample Pattern for one-sided pile.

Example Pattern for a One-sided Pile

Figure 4(a)
b) Stream Sampling

A bulk fertilizer may be sampled from the "stream" as the fertilizer is being transferred or loaded into or out of a bulk container such as a tote box or truck body. At least ten (10) equal – time – spaced samples are to be taken from the stream so as to represent the whole lot. Use the AOAC sampling cup to take the sample.

Stream Sampling Cup. Fabricate from: 16 GA Galvanized Iron, or 18-20 GA Stainless Steel, Type 304.

Stream Sampling Cup

Figure 4(b)

When the full flow rate of transfer would be too fast to get a good sample, it may be necessary to have the operator reduce the rate of flow of the lot being sampled. If flow rate cannot be satisfactorily reduced, sample static lot using "Missouri D Tube" trier. Sampling from the stream is preferable to sampling from a static lot.

Use of stream sampling cup for belt samples

Use of stream sampling cup for belt samples

3. Liquid Products Non-Pressurized

  • Products containing no Free Ammonia

    Containers of over one liter (Approximately 1 kg) agitate the container and remove a representative sample of 500 ml by pouring, syphoning or ladling. One unopened container may constitute the sample.

    Note: Products containing free ammonia are easily identified by their characteristic odour.

  • Suspensions and Slurries

    Agitate material in storage for more than 15 minutes before taking sample. The preferred points for sampling in order of preference are:

    1. directly from the mixing vat;
    2. top opening of storage or transport; and
    3. from delivery line or recirculating line immediately after a large quantity of material has been pumped out.

    When securing sample directly from mixing vat or from top opening of storage or transport use 500 ml sampling bottle with 6-9 mm fluid intake tube and air escape hole 12 mm in diameter with attached weight greater than 700 grams. Lower sampling bottle from top opening to bottom of tank and raise slowly while filling.

    Samples secured from tap or recirculating line after agitating and recirculating simultaneously for more than 15 minutes may be taken in a standard 500 ml plastic bottle.

Part B – Size of Sample

  • Dry: For mixed fertilizers where a composite sample has been taken, a sample may range in size from 2 to 4kg. The whole sample is to be sent to the laboratory. For unmixed fertilizers, e.g. bonemeal, superphosphate, reduce the sample to 1 kg for submission in standard sample bag.
  • Liquids: For liquid products the sample should be at least 500 ml.

Part C – Sample Container

Fertilizer without Pesticides

  • Dry: Use the standard laminated sample bag or the large polyethylene sample bag.

    Note: A one bag sample submitted in the unopened manufacturer's packaging, is acceptable for products 11 kg or less in weight (eg. homeowner use products).

  • Liquids: Use glass sealers except for solutions containing free ammonia (including suspensions) where one litre plastic bottles are to be used. The sample containers must be sealed to preserve the physical and chemical condition and amount of the sample.

Fertilizers with Pesticides

  • Liquid and Dry

    Use only glass containers for fertilizer pesticide mixtures to minimize any loss through volatilization.

    Due to postal requirements, all fertilizer pesticide samples must be enclosed in a metal sealed container (such as paint cans) with appropriate packaging when using glass bottles.

    1. Glass containers must have teflon tops, or when not available, a clean aluminum foil, between the top and bottle, may substitute for the former.
    2. For liquid fert-pesticides, use kitty litter (or other absorbents) for packaging and a plastic bag to line the paint can.
    3. For granulars, packaging such as shredded newspaper can be substituted for the kitty litter.
    4. Make sure to label each sample with a sticker indicating at least the inspection sample number, fertilizer and pesticide guarantees, so that the laboratory can match the sample with appropriate sampling forms.
    5. Under the requirements of the Dangerous Goods Act the words "Test Samples" must appear on the packaging of these samples.

    Note: This should apply to all samples sent for analysis in order to assure that any constituent material not known by the inspector and subject to the Dangerous Goods Act (e.g. ammonium nitrate) is properly identified for shipping purposes.

Part D – Exposure of Sample

The actual time that the sample is exposed to the air should be as short as possible in order that the effect of moisture exchange may be kept at a minimum.

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