Soil Management Handbook - Ministry of Agriculture and Lands

Keremeos Soil Management Group
Soil Series: Cawston (CA), Coulthard (CD),
Keremeos (K), Nighthawk (NG) and
Snehumpton (SN)
General Characteristics: These soils have
developed on fluvial floodplain terraces and
consist of stone-free medium to coarse-textured
overlays which vary in depth from less than 25
cm to about 100 cm in thickness. These deposits
are underlain by very coarse-textured sandy and
gravelly deposits. The soils are well to
moderately-well drained. The topography ranges
from nearly level (0 to 0.5%) to very gentle
slopes (0.5 to 2.0%).
Dominant Soil Limitations:
• Spring flooding can occur during higher than
normal runoff in areas that are not dyked.
• A short duration fluctuating groundwater table
can occur in sandy and gravelly subsoils during
the spring freshet.
• Fluctuating watertables on Nighthawk and
Snehumpton soils may pose specific problems to
deeper rooting crops. These fluctuating
watertables may be associated with old channels
or proximity to current river channels.
Well Suited Crops: Where spring flooding does not
occur and surface soils are deeper than 60 cm
over gravels, all climatically adapted crops,
except asparagus and ginseng.
Suited Crops: Where surface soil depths range
between 30 to 60 cm over gravels - Nighthawk
and Snehumpton soils - all climatically adapted
crops, except asparagus and root crop vegetables,
are capable of producing high yields. The
limitation to asparagus and root crop vegetables
is the shallow depth of the surface soils to
gravels. Ginseng suitability may be limited due to
the possibility of temporary high watertables.
Management Inputs:
Organic Matter Incorporation: Incorporation of
organic matter is required to improve the
water-holding capacity and nutrient-holding
capacity of these soils.
Cover Cropping: Cover crops are required for grapes
and tree fruits.
Water Management System: Dyking is required for
some locations along the Similkameen River.
Unsuited Crops: Asparagus and root crop
vegetables are not suited on Nighthawk and some
areas of Snehumpton soils.
Reasons: The natural rooting habit of these crops
would be severely restricted, and therefore,
maximum yields might not be achieved.
Corrective measures are not feasible.
NOTE: Cawston soils mapped in the Okanagan
River Floodplain, north of Osoyoos Lake, are poorer
drained than Cawston soils in the Similkameen
Valley. This may be related to historic soil
development or their proximity to the Okanagan
River channel and its associated flood control
structures.
Soil Management Handbook – Okanagan-Similkameen Valleys 19