Soils of the - Agriculture and Agri-Food Canada

DEFEHR SOILS (DR)
Location and Extent : Defehr soils mainly occur in the vicinities of Haney, Port Hammond, Peardonville and
Abbotsford Airport although small, scattered areas are also present elsewhere on the uplands . There are abou t
360 ha of pure map units and 380 ha of soil complexes dominated by Defehr soils . The complexes are mainl y
with Lehman, Heron and Sunshine soils .
Topography and Elevation : The topography of Defehr soils is very gently to gently sloping and undulating .
Slope gradients range between 1 and 5 percent and elevations lie between 40 and 80 m above sea level .
Parent Material and Texture : Defehr soils have developed from coarse-textured (mainly sandy )
glaciofluvial and marine lag deposits, at least 2 m deep and usually underlain by glacial till or glaciomarine
sediments . A shallow veneer of medium-textured, eolian or slopewash material sometimes caps or is mixed into
the surface . Surface textures are sandy loam or loam while subsurface and subsoil textures vary from sand t o
gravelly sand . Occasional stones are sometimes present .
Soil Moisture Characteristics : Defehr soils are imperfectly drained . They are rapidly pervious and have
slow surface runoff and low water holding capacity. During periods of heavy rain, fluctuating, perche d
watertables develop above the less permeable geologic materials present at depth .
General Soil Description : Defehr soils have a friable, dark brown or dark yellowish brown, loamy, cultivate d
surface that is about 15 cm thick . The surface is underlain by about 40 cm of friable, weakly structured or loose ,
yellowish-brown or pale brown sand or loamy sand containing few to common, strong brown or reddish-brow n
mottles . This grades, below about 80 cm, to variably coloured, loose, gravelly sand or sand containing many
reddish or brownish mottles. Surface soil reaction is strongly acid, changing to medium acid in the subsurfac e
and subsoil. Soil classification is Gleyed Humo-Ferric Podzol.
Commonly Associated Soils : Lehman, Sunshine, Heron, Columbia and Abbotsford soils often occur i n
close association with Defehr soils, either in soil complexes or in adjacent map polygons . Sunshine soils are
generally similar to Defehr soils, except that they are well-drained and contain no mottles in the subsurface an d
subsoil . Heron soils, although also sandy, are poorly drained . Lehman, Columbia and Abbotsford soils are
gravelly rather than sandy in the subsoil . Additionally, Lehman soils are poorly drained while Columbia an d
Abbotsford soils are well to rapidly drained . Abbotsford soils also have a silty surface capping from 20 to 50 c m
thick .
Vegetation : Substantial areas of Defehr soils are cleared for agricultural or urban uses . Uncleared area s
support a variable forest of coast Douglas-fir, western hemlock, western red cedar, red alder, black cottonwoo d
and willow. Rooting is generally unrestricted to at least 60 cm depth, then becomes variably restricted by the
fluctuating watertables .
General Land Use Comments : (1) Most cultivated areas of Defehr soils are used for forage and pastur e
although most other crops are possible also . Low water holding capacity leads to droughty conditions in th e
summer and irrigation is required for good crop production . The fluctuating watertables which may damag e
some perennial crops during the winter can be controlled by artificial drainage . (2) Defehr soils are moderatel y
suited for urban and related uses . The fluctuating watertables may cause problems with basements and othe r
excavations . The operation of septic tank disposal fields is also impaired during the periods of high watertables .
(3) Data from a few plots indicate that Defehr soils produce good forest growth . Douglas-fir produces about 1 2
to 15 m 3 of wood/ha/yr. The low soil water holding capacity appears to be effectively offset by the fluctuatin g
watertables .
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