Soils of the - Agriculture and Agri-Food Canada

MONROE SOILS
Location and Extent : Monroe soils are common on the floodplain of the Fraser River east from th e
confluence with the Pitt River. The largest areas are in Matsqui Valley and on Nicomen Island . About 110 ha of
pure map units and 1290 ha of soil complexes dominated by Monroe soils are classified . The complexes are
mostly with Fairfield, Matsqui and Page soils .
Topography and Elevation : Monroe soils are mostly gently undulating or undulating, sometimes varying t o
gently or moderately rolling . Slope gradients are less than 10 percent . The soils occupy the topographicall y
higher landscape positions when in complexes with poorer drained soils . Elevations range from about 4 to 15 m
above sea level .
Parent Material and Texture : Monroe soils have developed from medium-textured, stone-free Fraser Rive r
floodplain deposits that are more than 50 cm deep and overlie coarse-textured deposits, mainly sand . Surface
and subsurface textures are usually silt loam, occasionally varying to fine sandy loam, loam or silty clay loam .
The upper subsoil textures are similar but change at depth to sand or loamy sand, sometimes interstratified wit h
thin, finer textured bands .
Soil Moisture Characteristics : Monroe soils are moderately well to well drained . They are moderatel y
pervious and have high water holding capacity and slow to moderate surface runoff . Temporary groundwate r
tables may develop in the subsoil during the freshet period on the Fraser River or during heavy, prolonged rain .
General Soil Description : Monroe soils generally have a grayish-brown, friable, cultivated silty surfac e
about 20 cm thick which is underlain by about 15•cm of brown or brownish-gray, friable, weakly subangula r
blocky to fine platy, partially leached, silty material . In turn, this is underlain by a dark brown to dark yellowis h
brown, friable, moderately subangular blocky zone about 50 cm thick that is slightly enriched with eluviate d
clay in the upper part and contains scattered clay flows and skins . It grades with increasing depth to loose san d
or, sometimes, sand interspersed with thin, finer textured bands and contains few to common, brownish o r
reddish mottles below about 100 cm . Casts and other evidence of earthworm activity are usually present in the
upper 50 cm . Soil reactions vary from very strongly or strongly acid in the surface and grade to medium o r
slightly acid at depth . Soil classification is Eluviated Eutric Brunisol .
Commonly Associated Soils : Fairfield, Matsqui, Dewdney and Page soils are usually associated in th e
undulating landscape with Monroe soils . Fairfield soils differ from Monroe soils by being imperfectly drained
and usually lie in slightly lower landscape positions . Matsqui soils have textures similar to Monroe soils but th e
underlying sand occurs within 20 to 50 cm of the surface ; Dewdney soils are similar to Matsqui soils an d
additionally, are imperfectly drained . Page soils, generally depressional in relation to Monroe soils, are poorl y
drained .
Vegetation : Most Monroe soil areas are cleared and cultivated . The remaining, small, uncleared area s
support, among others, black cottonwood, red alder, vine and bigleaf maple, birch, coast Douglas-fir, wester n
red cedar, occasional Sitka spruce, blackberry, thimbleberry, salmonberry, and grass . Rooting is unrestricted to
at least 100 cm depth .
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