Von Post

Attribute definition
Attribute Label VONPOST
Title Von Post
Description

Indicates the class of decomposition using the Von Post estimate of decomposition.

Classes Von Post method of decomposition


Classes
Code Class Description
01 Living moss layer

Living moss layer. Usually the surface 2-4 cm. Cannot be considered "peat" as such as it is not yet dead.

02 Plant material is dead

The structure and form of the plant material is complete. The only difference between 01 and 02 is that a 02 peat is not living. When squeezing, clear to slightly yellowish water is emitted. The peat sample in the hand is normally bright yellowish orange in colour, especially after squeezing. The sample is spongy, or elastic; upon squeezing, the compressed sample springs back, and will take little or no shape.

03 Plant material very easily distinguishable

The plant material is still very easily distinguishable, but the individual sphagnum "stalks" are breaking up into pieces, as opposed to continuous lengths of stems, etc. When squeezing, yellow water with some plant debris (mostly individual leaves is emitted. The colour of the sample is somewhat darker that a 02 peat. The sample is still spongy, but less than 02; after squeezing, the peat will spring back to a point where a vague to fairly definite form of the handprint is distinguishable.

04 Plant material disintegrating

The plant material is not as easily distinguishable as in 03 because the pieces of peat, as mentioned above, are now disintegrating, therefor one is often dealing with individual stems, branches, and leaves. When squeezing, light brown to brown water with a lot of debris is emitted. The sample is not spongy, and upon rubbing, a slightly soapy or humic texture is detected. Upon squeezing, the sample makes a perfect replica of the handprint, commonly called "brass knuckles". It should be noted that after squeezing a peat sample, the difference in shape between a 03 and a 04, is that a 03 is "rounded off" whereas a 04 peat has definite "sharp" ridges left by the fingers. No peat escapes the fingers.

05 Some unstructured material is present

The plant material is reaching a stage of decomposition where the individual components (branches, leaves, stem) are starting to breakup, such that some amorphous or unstructured material is present. When squeezing, definitely brown water is emitted. This water is reaching the point where it can no longer be termed "water", but is a solution. The sample has a more definite soapy or humic texture, yet roughness is still present. Upon squeezing a very small amount of the sample escapes between the fingers.

06 Half of the material is unstructured

The plant material has decomposed to the extent where almost half of the sample is in an amorphous or unstructured state. Plant constituents are still distinguishable upon close examination in the hand. upon squeezing, brown to dark brown water is emitted. The sample is pasty and very malleable. Upon squeezing, approximately one-third of the peat escapes between the fingers as a paste.

07 Plant material practically indistinguishable

The original plant material is practically undistinguishable and a very close examination in the hand is needed to see that there are still vague structures present. If the sample is "worked" in the hand, this structure will disappear. It should be noted that such things as weed, sedge roots, and Eriophorum fibres are often very resistant to decomposition, and can be present in their "original" state in humified peats up to 07. Upon gentle squeezing, a small amount of very dark water is emitted. When the final squeeze is performed, over half of the material escapes the hand.

08 No appreciable roots or fibres

The only distinguishable plant remains are roots or Eriophorum fibres, when present. If appreciable amounts of roots or fibres are present, the peat cannot be considered to be a 08, even though the remaining material is such. The "appreciable amount" of these materials occur when they interfere with the squeezing out of the remaining amorphous material. If pieces or chips of weed are present in the sample, regardless of the amount, this alone classifies the peat as a 07. Little or no water is emitted upon gentle squeezing. The final squeeze results in over two thirds of the peat escaping the hand.

09 Homogeneous amorphous

A very homogenous, amorphous sample containing no roots or fibres. There is no free water emitted upon squeezing, and almost all of the sample escapes the hand.

10 Pudding-like homogeneous

Very rare to non-existent in non-sedimentary peats. In sedimentary peats, the particle size can be extremely small resulting in "pudding-like" homogenous material. Upon squeezing, all of the sample escapes the hand.

-9 not applicable

not applicable

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