Soils of the - Agriculture and Agri-Food Canada

FADDEN SOILS (FD)
Location and Extent : Fadden soils occur only in scattered areas in the western part of Sumas Valley, mainl y
south of Kilgard . There are about 280 ha of pure map units and 45 ha of soil complexes dominated by Fadde n
soils . The complexes are mostly with Bates and Vye soils .
Topography and Elevation : Fadden soils are gently undulating to undulating with slopes up to 4 percent .
They commonly occupy the tops and upper slopes of the undulating landscape . Usual elevations are betwee n
5 and 10 m above sea level .
Parent Material and Texture : Fadden soils have developed from moderately fine to medium-texture d
lacustrine deposits . At depths greater than 1 m sand is often encountered and thin, buried, old, surfaces ar e
sometimes present at about 90 cm depth . Surface textures are silt loam or silty clay loam ; subsurface an d
subsoil textures are generally silty clay loam or silty clay, changing to medium or coarse sand below 1 m or more .
Soil Moisture Characteristics : Fadden soils are imperfectly drained . They are moderately pervious an d
have high water holding capacity and slow to moderate surface runoff . The fluctuating groundwater table i s
usually high during the wet, winter months but recedes during the drier, summer period . In slightly depressiona l
locations, occasional surface ponding occurs after heavy rains .
General Soil Description : Fadden soils have a black to very dark brown, friable, silty, cultivated surface tha t
is between 15 and 20 cm thick . It is underlain by about 20 cm of gray to grayish-brown, friable, leached, silt y
material containing a few, strong brown mottles . Under this is a dark grayish brown to dark gray, clay enriche d
layer about 50 cm thick which has strong, coarse, prismatic structure and many, strong brown mottles ,
particularly in the lower part . The soil then grades, below 1 m or more, to loose sand containing reddish-brown
mottles . Soil reaction grades from strongly acid in the surface to slightly acid in the subsoil . Abundant casts an d
other evidence of earthworm activity is present in the surface layers . Soil classification is Gleyed Gray Brown
Luvisol.
Commonly Associated Soils : Bates, Vye, Vedder and Buckerfield soils often occur in dose associatio n
with Fadden soils, either in soil complexes or adjacent map polygons . Bates soils are similar to Fadden soil s
except that the well defined clay accumulation layer in the subsoil is absent . Vye soils are also similar to Fadde n
but have lighter coloured surfaces containing less organic matter. Vedder and Buckerfield soils differ fro m
Fadden soils by being poorly drained and usually lie in slightly lower topographic landscape positions whe n
compared to the imperfectly drained Fadden soils .
Vegetation : All areas of Fadden soils are cleared and cultivated . Rooting is partially restricted below about 6 0
cm by the clayey subsoil layers and fluctuating winter watertables although roots commonly penetrate t o
depths of 100 cm .
General Land Use Comments : (1) Fadden soils are well suited for most agricultural crops although high ,
periodic watertables hinder the overwintering of some perennials and the growth of other crops particularl y
sensitive to "wet-feet" . Artificial drainage and periodic subsoiling to loosen the dense, clayey subsurface layer s
lessens these problems . (2) Variable (usually low) soil bearing strengths can produce subsidence problems i f
heavy structures are erected and high, periodic watertables discourage basements and other excavations . Th e
operation of septic tank disposal fields is restricted by periodic high groundwater and relatively low subsoi l
permeability. (3) Fadden soils appear well suited for forest crops such as cottonwood . Potential productivity fo r
this species is estimated at about 9 to 12 m 3 of wood/ha/yr.
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