Soils of the - Agriculture and Agri-Food Canada

ALOUETTE SOILS . (AL)
Location and Extent : Alouette soils occur only on the lowlands of Pitt Meadows and Coquitlam Municipalities
and in the southern part of Pitt Polder . There are about 1460 ha of pure map units and a further 810 ha o f
soil complexes which are dominantly Alouette soils . The complexes are mainly with Pitt, Sturgeon and Neave s
soils .
Topography and Elevation : Slightly depressional to undulating with slopes less than 3 percent is the usua l
topography of Alouette soils . All occur at elevations below 5 m above sea level . In complexes with Pitt soils ,
Alouette soils occupy the slightly lower landscape positions .
Parent Material and Texture : Alouette soils have developed from shallow organic accumulations which ar e
underlain by mixed Fraser, Alouette and Pitt river floodplain sediments . Textures consist of 15 to 40 cm of well -
decomposed (humic) organic material (sometimes containing a proportion of silt) overlying silt loam for a metre
or more . At greater depths, medium or fine sand usually occurs .
Soil Moisture Characteristics : Alouette soils are poorly to very poorly drained . They are moderately
pervious and have high water holding capacity, and slow surface runoff. In undeveloped areas the watertable i s
at or near the surface during the winter and after other heavy rains . All developed areas are ditched an d
substantial areas are also tile drained .
General Soil Description : The surface of Alouette soils consists of 15 to 40 cm of black or very dark brown ,
friable, well-decomposed organic material . This is underlain by about 15 cm of dark grayish brown, silt y
material commonly containing vertical cracks filled with organic matter from above . Below this, the soil consist s
of massive, grayish-brown to olive-gray silty material to 1 m or more and contains common to few, reddish an d
yellowish mottles . Soil reaction varies from extremely acid in the upper soil to very strongly acid in the subsoil .
Soil classification is Orthic Gleysol : peaty phase .
Commonly Associated Soils : Pitt, Sturgeon and Neaves soils are usually closely associated with Alouette
soils . Pitt and Neaves soils differ from Alouette soils in that their surfaces are silty (Neaves) or clayey (Pitt) rathe r
than organic . Sturgeon soils usually do not have the prevalent subsurface cracking of Alouette soils . All ,
however, are poorly drained .
Vegetation : Most areas of Alouette soils are used for agriculture, mostly for forage and pasture . Undevelope d
areas generally support a growth of hardhack, sweet gale, reeds and sedges . Rooting depths are restricted to
about 60 cm by high groundwater tables .
General Land Use Comments : (1) The main agricultural limitations of Alouette soils are poor drainag e
(high watertables) and susceptibility to surface ponding during the winter and other periods of heavy rain . The y
are presently used mostly for grass-clover pasture and forage production and some silage corn and oats as wel l
as for blueberries and as nursery sites . Improved water control will widen the range of possible crops . Alouette
soils are very acidic and liming to raise the pH is beneficial for most crops . (2) Low soil bearing capacity an d
high water tables make road and building construction difficult . High watertables discourage basements an d
other excavations while the efficiency of septic tank effluent disposal fields is severely impaired . (3) Alouette
soils are estimated to be moderately capable of producing forest species tolerant of high water tables, such a s
western red cedar. Growth of this species is estimated to be about 6 to 8 m 3/ha/yr.
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