Soils of the - Agriculture and Agri-Food Canada

PITT SOIL
(P)
Location and Extent : Pitt soils occur only in Pitt Meadows and Coquitlam Municipalities and in the sout h
parts of Pitt Polder. About 910 ha of pure map units and 700 ha of soil complexes dominantly Pitt soils ar e
mapped . Most complexes are with Alouette and Katzie soils .
Topography and Elevation : Topographically, Pitt soils are gently undulating to undulating with slopes les s
than 4 percent . They usually occupy slightly higher landscape positions than adjacent soils and often occur a s
slightly raised, sinuous, discontinuous ridges . Elevations are less than 4 m above sea level .
Parent Material and Texture : Pitt soils have developed from moderately fine textured, stone-free, mixe d
floodplain deposits of the Fraser, Alouette and Pitt Rivers . Surface textures are either silt loam or silty clay loa m
while the subsurface is mainly silty clay loam with some variation to silty clay. The subsoil is silt loam to at least 7 5
cm depth, then sometimes gradually grades to more sandy material .
Soil Moisture Relationships : Pitt soils are poorly to moderately poorly drained . They are slowly to
moderately pervious and have high water holding capacity, and slow to moderate surface runoff . Groundwate r
tables are near the surface for most of the rainy winter period but usually gradually recede during the growin g
season .
General Soil Description : Pitt soils generally .have a black, moderately structured, friable, cultivated, silt y
surface layer about 20 cm thick that contains about 20 percent organic matter. This is underlain by about 30 c m
of gray, very firm, coarsely prismatic, silty to clayey soil containing many to common, strong brown to yellowish -
red mottles and, in the upper part, common clay flows on crack surfaces and in old root channels . This zone i s
then underlain by at least 30 cm of massive, friable to firm, dark gray to olive-gray, silty material containin g
common to few, dark brown to yellowish-red mottles, mainly along old root channels . At greater depths sand i s
sometimes encountered . Soil reaction grades from extremely acid in the surface to strongly or medium acid i n
the lower subsoil . Soil classification is Orthic Humic Gleysol.
Commonly Associated Soils : Alouette and Katzie soils are often in close association with Pitt soils .
Alouette soils usually lie in slightly lower landscape positions than do Pitt soils and have organic surfaces fro m
15 to 40 cm thick . Katzie soils differ from Pitt soils by being somewhat less poorly drained ; they also have
strongly mottled subsurface layers and usually lie in slightly higher landscape positions .
Vegetation : Almost all areas of Pitt soils are cleared and cultivated . Vegetation along fence lines and in othe r
uncleared locations includes black cottonwood, western red cedar, blackberry, salmonberry, hardhack ,
sedges and grass . Rooting is restricted mainly to the upper 60 cm by the high groundwater tables and dens e
soil material .
General Land Use Comments : (1) Poor drainage and high watertables are the main agricultural limitatio n
of Pitt soils and artificial drainage is beneficial for crop production, especially for maintenance of perennia l
crops . Severe acidity is also a problem for some crops and this can be ameliorated by adequate liming . Pitt soil s
are usually closely intermingled with other soils (often Alouette) which makes them difficult to manag e
individually. (2) Pitt soils are poorly suited for urban or similar uses . Variable bearing strengths make specia l
foundations a consideration while high watertables generally preclude basements and other excavations . Hig h
watertables and relatively low permeability severely impede efficient disposal of septic tank effluent . (3) Pit t
soils appear moderately suited for the growth of trees such as black cottonwood . Potential annual woo d
production by this species is estimated at 12 to 15 m 3/ha .
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