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Using the.scii-water method, mosti-of'the lowiand minera1 soils
are mildly to moderately alkaline (pH: 7 - 8) throughout the solum
(A and B horizons) while the parent material is moderately alkaline.
This is due to the high lime parent materialtihich was deposited by
the Kootenay.River since the retreat of the valley glacier. Sulphur
content is low in a11 profiles except those of the Simmons,
Kuskanook, Shaw, and Cory series where it is high.
The 0,Ol.M CaC12 pH method reduces the effect of varying concentrations
of soi1 salts and is more nearly the pH of the soi.1 solution
under actual field conditions. Values by this method for the same
lowland soils are usually 0.5'to 1,O pH units less thon tqith water.
In the upland soils, the sdla are generally neutral in reaction
while the parent materials tend to be mildly alkaline.
Plants vary in their ability to grow at differenc pH valuss.
Qthough pH itself may not be responsible for limiting growth,
nutrient availability to various plants at different pH values is
significant. For example, in alkaline soils of the semi-arid and
arid regions, or when soils are over-limed, growth may be curtailed
by low availability of iron, mnganese, and linc. In some acid soils
on the other hand, manganese, iron -nd ali.inum may be solubilized
to the etient of being toxiè to many plants.
In this map area there seems to be little need to incorporate
lime into the soil. Most if not a11 lowland soils have adequate
levels of lime. In the upland soils of the Creston area, ph c,lone
camo-t be used to estimate the nmount'and'frequency of iiming.
Better criteria appear to be ccncentration of solub1.e and exchangeable
aluminum and mnngazee or the exchangeable aluminum-c' bcium ratio,
The importance of this ratio is borne out by the accumulating ev3Ldence
that aluminum and/or manganese toxicity is the main factor responsible
for -poor growth .in acid soils. The most important function oï
liming, therefore, is to reduce the concentra,tion of soluble and
exchangeable aluminum and manganese in the soil.
Less lime per application is. required for conrse textured soila
with lob*; cation exchange capacities than for :~~I.:-.er- textured soi13
with higher sxchange capacities to raise the pH a ‘simj.1.a.r smcunt.
Some soi1 borne diseases cari be controller by varyi.ng pH since t,he
disease organisms un survive only in a rel.ationly narro::r pi-I ra.r:ge e
.Organic
Natter ..-
Soi1 3lgâiliC matter results from -i,he decomposiC,i.~~i 21-d incoTporBt~i::il
of leaves, twigs, roots and other organic material. The amou&
which accumulates is related to precipitation, drainage, v-egetation,
temperature and other factors. It rai2 vary from less thazi aze
percent in minera1 sails ta lCC$ in organic ones. In c 7, -p- f T;:, i, :;:$.
minera.1 soilsp organic mat-ter .îl3iiltvnance 3-s ve-v ijllpO'tLTit j