Soils of the - Agriculture and Agri-Food Canada

SUMMER SOILS (SR)
Location and Extent : Summer soils are relatively uncommon and occupy small areas on the uplands ,
mainly in the central part of the map area. About 55 ha of pure map units and 630 ha of soil complexe s
dominated by Summer soils are mapped . Most complexes are with Heron, Sunshine and Livingstone soils .
Topography and Elevation : Summer soils are nearly level to gently undulating and often are slightl y
depressional in relation to adjacent, better drained soils . Slope gradients are less than 5 percent and elevation s
range between 20 and 150 m above sea level .
Parent Material and Texture : Summer soils have developed from coarse to moderately coarse texture d
(sandy) littoral or glaciofluvial deposits, usually from 50 to 100 cm thick, which overlie moderately fine to fine -
textured marine or glaciomarine sediments . Surface textures are sandy loam or fine sandy loam while th e
subsurface and upper subsoil vary from loamy sand to sand . The subsurface layer is strongly cemented . The
lower subsoil, consisting of the underlying marine and glaciomarine materials, varies from silty clay loam to clay .
Soil Moisture Characteristics : Summer soils are imperfectly to moderately poorly drained . They are slowl y
pervious and have low water holding capacity and slow surface runoff . Periodic, temporary surface pondin g
occurs during heavy, prolonged rains due to raising of the perched watertable above the clayey subsoil . The
perched watertable usually disappears during the latter part of the summer and moisture deficiencies ar e
common towards the end of this period .
General Soil Description : Where cultivated, the surface layer of Summer soils consists of about 15 cm of
black to very dark gray, very friable, loamy material . This is underlain by about 10 cm of gray to brownish-gray ,
very friable, strongly leached, sandy material . Under natural conditions about 5 cm of organic forest litter and ,
sometimes, 10 to 15 cm of dark gray or very dark gray, friable, partially leached, sandy material overlies th e
strongly leached zone . The leached zone is abruptly underlain by 10 to 20 cm of very dusky red to dark reddis h
brown, strongly cemented, sandy material which is extremely firm when moist and extremely hard when dry . Th e
cemented zone is underlain by about 15 cm of brown to yellowish-brown, partially cemented, sandy materia l
containing a few reddish mottles . Under this is about 50 cm of olive-gray or gray sand with common, reddish o r
brownish mottles . Gray, massive, clayey deposits occur at about 100 cm depths . Soil reactions gradually grad e
from extremely or very strongly acid in the surface to slightly acid in the clayey subsoil (1 :1 H 20) . Soi l
classification is Gleyed Ortstein Humo-Ferric Podzol.
Commonly Associated Soils : Heron, Sunshine, Bose and Boosey soils often occur in close associatio n
with Summer soils . Heron and Boosey soils differ from Summer soils by being poorly drained . They also lack a
cemented subsurface layer and, as well, Boosey soils are gravelly in texture . Bose and Sunshine soils differ b y
being well or moderately well drained . They also lack a cemented subsurface layer and additionally, Bose soil s
are gravelly.
Vegetation : Cleared areas are used mainly for pasture and forage production . Uncleared areas support a
variety of species tolerant of periodic wet conditions and include western red cedar, western hemlock, red alde r
and blackberry. Most rooting is restricted to the upper 30 cm by the dense, cemented subsurface layer .
General Land Use Comments : (1) Agricultural use of Summer soils is mainly restricted by high winte r
watertables which adversely affect perennial crops and by limited rooting depth and droughty conditions whic h
develop during the latter part of the growing season . Adequate watertable control, subsoiling to disrupt th e
cemented layer and supplemental irrigation as required (as well as adequate fertilization), make Summer soil s
suitable for most crops . (2) Urban use of Summer soils is restricted by periodic high watertables whic h
adversely affect basements and other excavations and, together with slow subsoil permeability, retards efficien t
operation of septic tank disposal fields . (3) Forest growth, which is mostly western red cedar, is moderate and i s
limited mainly by restricted rooting depth . Estimated annual wood production by western red cedar and Sitk a
spruce is about 7.5 to 9 m 3/ha.
183