Soils of the - Agriculture and Agri-Food Canada

PELLY SOILS (Pl )
Location and Extent : Pelly soils occur only as small areas in Chilliwhack Municipality, south and west o f
Chilliwack Mountain . About 30 ha of pure map units and 25 ha of soil complexes dominated by Pelly soils are
mapped . The complexes are with Blackburn and Annis soils .
Topography and Elevation : Pelly soils are nearly level to gently undulating . They have slopes up to 2
percent and usually are slightly depressional in relation to adjacent soils . Elevations vary between 5 and 10 m
above sea level .
Parent Material and Texture : The parent material of Pelly soils are moderately fine to medium-textured ,
stone-free, Fraser River floodplain deposits at least 50 cm thick which overlie sand . Surface textures are usuall y
silty clay loam with some variation to silt loam or silty clay . Subsurface textures are similar while the subsoi l
gradually changes to silt loam with depth and sometimes contains lenses of sand or loamy sand .
Soil Moisture Characteristics : Pelly soils are poorly drained . They are slowly to moderately pervious an d
have high water holding capacity and slow surface runoff . Groundwater tables are near the surface during mos t
of the winter and during the freshet period on the Fraser River but recede gradually over the growing season .
Surface ponding is common during heavy, prolonged rains due to slow permeability and runoff accumulatio n
from adjacent, higher areas .
General Soil Description : Pelly soils generally have a silty, cultivated surface layer about 20 cm thick whic h
is friable and very dark grayish brown in colour. It is underlain by a gray to dark gray, firm, sticky, coarsel y
structured, silty to clayey zone about 20 cm thick that contains few to common, yellowish-brown mottles . Thi s
zone is underlain by 40 cm or more of gray to olive-gray, firm, sticky, massive, silty material containing commo n
to few, yellowish-red mottles . At depth, the silty material often contains lenses of sand . Soil reaction ranges fro m
strongly acid in the surface and subsurface to medium or slightly acid in the subsoil (1 :1 H 20). Soil classificatio n
is Orthic Humic Gleysol .
Commonly Associated Soils : Blackburn, Annis and Grigg soils are commonly closely associated wit h
Pelly soils . Annis soils differ from Pelly by having between 15 and 40 cm of organic material at the soil surface .
Blackburn soils differ by containing buried (dark coloured), old surface layers in the subsurface and subsoil .
They usually also lie slightly higher than Pelly soils and are somewhat less poorly drained . Grigg soils differ b y
being imperfectly drained and contain a well-defined clay accumulation layer in the subsurface .
Vegetation : All areas of Pelly soils are cleared and cultivated . Natural vegetation along fences and in simila r
locations includes black cottonwood, thimbleberry, salmonberry, blackberry, willow, sedges and grass . Rootin g
is mainly restricted to the upper 60 cm by the high groundwater levels and massive subsoil .
General Land Use Comments : (1) Poor drainage and high groundwater levels are the main agricultura l
limitation of Pelly soils . Artificial drainage is required for good crop production, particularly for overwintering o f
perennial crops and will also allow earlier cultivation in the spring . Pelly soils are usually closely intermingle d
with other, usually somewhat better drained soils which makes them difficult to manage individually . (2) Urban
and similar developments are poorly suited for Pelly soils . High watertables preclude basements or othe r
excavations and variable bearing strengths may require special foundations . High watertables and relativel y
slow permeability severely impede septic tank effluent disposal . Periodic flooding during heavy rains is a severe
urban limitation .
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