Soils of the - Agriculture and Agri-Food Canada

Soil Moisture Characteristics : Columbia soils are well to rapidly drained . They are rapidly pervious an d
have slow surface runoff and low water holding capacity. They are droughty during most summers .
General Soil Description :
Columbia soils usually have 5 cm or less of forest litter on the soil surface . This i s
underlain by a thin (less than 2 cm), discontinuous, grayish, sandy, leached layer, which, in turn, is underlain b y
about 15 cm of sandy or loamy, friable, reddish-brown, brown or yellowish-brown material . This material grade s
to about 40 cm of similarly coloured, loose gravel or gravelly sand . Below about 80 cm, unweathered, loose ,
stratified gravel and gravelly sand occur. Stones and cobbles are common throughout . Soil reactions rang e
from strongly acid in the surface layers to medium or slightly acid in the lower subsoil . Soil classification is Orthic
Humo-Ferric Podzol.
Commonly Associated Soils :
Abbotsford, Lynden, Lehman and Defehr soils often occur in soil complexes
with Columbia soils or occupy adjacent lands . Abbotsford soils differ from Columbia soils by having 2 0
to 50 cm of silty material over gravel or gravelly sand . Lynden soils are sandy rather than gravelly in texture whil e
Lehman and Defehr soils respectively, are poorly and imperfectly drained .
Vegetation :
Large areas have been cleared and are utilized for agricultural or urban uses . Uncleared areas
support a mixed forest which includes coast Douglas-fir, western hemlock, grand fir, red alder, birch and maple .
The understory includes salai, bracken, thimbleberry and various mosses . Other than impediments imposed
by the gravelly subsoil, no restrictions to rooting occur to depths of 100 cm or more .
General Land Use Comments :
(1) Agriculturally, Columbia soils are limited by low water holdin g
capacity, relatively low fertility and stoniness . With adequate fertilization and irrigation (and stone picking a s
required), most crops can be produced satisfactorily. (2) Columbia soils are well suited for urban and simila r
uses . They are well drained and have good bearing strength and level topography . However, effluent fro m
numerous septic tanks can potentially contaminate groundwater through incomplete filtration in the coarse -
textured, gravelly subsoil . Columbia soils are usually good sources of aggregate . (3) Forest production o n
Columbia soils is moderate . Limited plot data indicates growth of coast Douglas-fir to be about 6 to 8 m 3/ha/yr.
Droughtiness during the latter parts of the growing season seems to be the main growth limitation .
(CL)
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