The use of quantified structural descriptors to physically characterise stockpiled milled peat of different genetic origins

• Published in: Geoderma Vol. 95; no. 1; pp. 15 - 32
• Main Authors: Mooney, S.J, Holden, N.M, Ward, S.M, Collins, J.F
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2000; Elsevier
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; image analysis; milled peat; pores; Soils; structure; Surficial geology; water movement; Ireland; Western Europe; milled peat; water movement; image analysis; structure; pores; physical properties; orientation; water storage; Europe; porosity; water content; particles; soils; peat; dimensions
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/S0016-7061(99)00069-5

Recent research examining water movement in milled peat stockpiles has focused on macroscale physical data. Structure is important with respect to water movement and storage; the number, shape and size of macropores is thought to be particularly important in influencing by-pass flow. A study of pore structures quantified by image analysis techniques was conducted starting with a field impregnation to produce undisturbed polished blocks from stockpiled milled peat of fen and raised bog origins. Samples were prepared in two orientations and characterised in two dimensions, parallel and orthogonal to the stockpile surfaces. Milled peat stockpile structure was found to be layered, with the surface layers typically twice as porous, but with half the number poroids of, the main body of the stockpile. This structure created a discontinuity between surface and sub-surface structures which was thought to be the result of rain, wind and gravity removing finer particles from the surface. Quantified evidence suggested that the milling processes differed in detail (smaller pores and finer particles from the fen peat). The quantified pore structures were consistent with the current hypothesis regarding milled peat stockpile rewetting mechanisms such as by-pass flow and finger storage. This suggested that structural properties are a more useful indication of rewetting mechanisms than a classification based only on peat density.