Soils of the - Agriculture and Agri-Food Canada

NICHOLSON SOILS
Location and Extent : Nicholson soils occur throughout the uplands of the map area but are most common i n
Langley, Surrey and Matsqui Municipalities . About 640 ha of pure map units and 4820 ha of soil complexe s
dominated by Nicholson soils are mapped . The complexes are usually with Whatcom, Scat, Albion, Bose an d
Sunshine soils .
Topography and Elevation : The topography of Nicholson soils is mostly undulating to moderately rollin g
with slopes between 2 and 15 percent . Some steeply or very steeply sloping gullies and escarpments with
slopes over 50 percent also occur. Nicholson soils are usually located on the tops and upper slopes of th e
ridges and knolls in the uneven landscape . Elevations range from 15 to 115 m above sea level .
Parent Material and Texture : Nicholson soils have developed from moderately fine and sometimes fine -
textured, compact, glaciomarine deposits which contain a few pebbles and stones . In the eastern half of the
map area, variable amounts of silty, eolian material, up to 25 cm thick, either overlies or is mixed into the surfac e
of the glaciomarine deposits . Surface textures are usually silt loam, with some variation to loam or silty clay loam .
Subsurface textures are silt loam or silty clay loam while the subsoil ranges from silty clay loam to silty clay or ,
occasionally, clay.
Soil Moisture Characteristics : Nicholson soils are generally moderately well drained although som e
imperfectly drained areas are also included . They are moderately pervious in the surface and subsurface layers
but this decreases to slowly pervious in the compact subsoil . They have high soil moisture holding capacity and
moderate to slow surface runoff, depending on steepness of the slopes . A temporary, perched watertabl e
usually develops above the compact subsoil during periods of heavy rain and lateral seepage along the surfac e
of the compact material occurs at this time .
General Soil Description : Nicholson soils, when cultivated, have a dark reddish brown, weakly structured ,
friable, silty surface about 15 cm thick . This is underlain by a yellowish-red to reddish-brown, friable, weakl y
structured zone about 20 cm thick that contains variable amounts of small, sherical, hard, reddish-brow n
concretions (these somtimes occur in the surface also) . Under this, in turn, is a firm, subangular blocky ,
yellowish-brown to pale brown, silty, partially leached zone about 10 cm thick which contains few to common ,
reddish mottles . The leached zone grades to gray or dark grayish brown, clayey material about 50 cm thick tha t
is very firm when moist, extremely hard when dry, cracks into coarse, prismatic peds, and contains numerou s
clay flows on ped surfaces . This clay enriched zone grades to dark grayish brown or brown, compact, clayey ,
unweathered glaciomarine sediments below about 100 cm . The unweathered material fractures conchoidall y
and has black castings on fracture faces . Soil reaction gradually increases from very strongly acid in the surfac e
to slightly acid or neutral below about 100 cm . The unweathered material fractures conchoidally and has blac k
coatings on fracture faces . Soil reaction gradually increases from very strongly acid in the surface to slightl y
acid or neutral below about 100 cm . Soil classification is mainly Podzolic Gray Luvisol although some Orthi c
Humo-Ferric Podzol areas are also included where the clay enrichment in the subsoil is not sufficient to meet th e
criteria of Luvisolic soils .
Commonly Associated Soils : Whatcom, Scat, Albion, Sunshine and Bose soils are usually closel y
associated with Nicholson soils, either as components of soil complexes or occupying adjacent map polygons .
Whatcom soils are similar to Nicholson soils except that the clay enriched subsoil layer occurs at greater depth .
Scat and Albion soils both differ from Nicholson soils by being poorly drained ; they also have black surfaces .
Sunshine and Bose soils differ by respectively having sandy and gravelly surface and subsurface layers ove r
clayey deposits similar to those of Nicholson soils .
Vegetation : Substantial areas of Nicholson soils are cleared and cultivated . The remaining, uncleared areas
support a variable second-growth forest including coast Douglas-fir, western red cedar, red alder, vine maple ,
cascara and some western hemlock . The understory contains a variety of species including thimbleberry,
salmonberry, bracken, blackberry, and moss . Rooting is mainly restricted to the upper 50 to 60 cm by th e
dense, compact, clayey subsoil .
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