What IS Muck?

Muck soils are a unique soil type that exists in pockets across Ontario including in the Holland Marsh and surrounding marshes, Keswick, Thedford, Grand Bend, and Leamington Marshes. They are found in low-lying areas, usually bogs or marshes, which have been drained. The organic matter, commonly peat, that is found in the bottom of these bogs forms the basis of the soil. The peat base also gives the soil a spongy texture which is most noticeable when walking through a field and feeling the bounce. It has several characteristics that separate it from mineral soil including colour, organic matter content, fertility, and size.

Figure 1: Examples of (from left to right) sandy, silty, clay, and muck soils. [Sources: http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/office/ssr7/tr/?cid=nrcs142p2_047969 / http://nesoil.com/images/enfieldRI.htm / http://www.nrcs.usda.gov/wps/portal/nrcs/detail/nj/soils/?cid=nrcs141p2_018867 / http://www.cals.uidaho.edu/soilorders/histosols_04.htm ]

These soils are easily identified by their colour (Figure 1). Muck has a high concentration of tannins which gives it the distinct black colour. Organic matter, which can be divided into three categories of plant residues and living microbes, detritus, and humus, form less than 10% of mineral soils (CUCE, 2008). Muck soils are made up of between 20 and 80% organic matter. Soil fertility is tied directly to the decomposition of plant residues, dead microbes, and detritus; because of the greater proportion of organic matter present, muck soils are more fertile than mineral soils (CUCE, 2008).

Muck soils are comparatively similar to clay and silt particles in size, but have less than half the specific gravity of them (Table 1). The muck particles also don’t aggregate like mineral soils. Thus, even though individual particles of mineral soils can be quite small, the aggregation will create a larger mass. The lack of aggregation in muck soils combined with the low specific gravity means that muck is susceptible to being picked up by the wind and blown around, creating something that is similar to a sand storm.

Figure 2: Particle size of sand, silt, and clay. [Source: http://croptechnology.unl.edu/Image/NolanDiane1129928529/figure2-2.jpg]

References

• Cornell University Cooperative Extension. (2008). Soil Organic Matter. In Agronomy Fact Sheet Series. Retrieved December 5, 2014, from http://franklin.cce.cornell.edu/resources/soil-organic-matter-fact-sheet
  
• Ou, C.-Y. (2006). Deep excavation: Theory and practice (p. 8). London, UK: CRC Press.
  
• Venkatramaiah, C. (2006). Geotechnical Engineering (3rd ed., p. 32). New Delhi, India: New Age International.
  
• Fratta, D. O., Puppala, A. J., & Muhunthan, B. (2010). GeoFlorida 2010: Advances in analysis, modeling & design (p. 2753). N.p.: ASCE Publications.