The Soils of The Regional Municipality of Ottawa=Carleton

Table 13 . continued
Soil
Association
'where no soil erodibility valueis given theerodibility classhas been estimatedbased onfield observations andcomputed valuesfrom
otherdrainage classes oftheassociation andgeneralvaluesforsimilarsurface texturesfrom Table 15 .
Table 14 also categorizes the various soils into five soil
erodibility classes (negligible to very severe) based upon their
respective K-values. The guidelines used for establishing these
soil erodibility classes are given in Table 14 . The soils in the
Ottawa-Carleton Region range from negligible to severe .
The particle size distribution (% sand, silt and clay) and
organic matter content are important factors in determining
soil erodibility. Table 15 provides an alternative method of
approximating K-values, if only soil texture and organic matter
content are known. The K-values reported in Table 15 were
computed from data gathered from almost 100 surface horizons,
sampled duringthe soil mapping of the Ottawa-Carleton
Region . If thetextural class is known, but not the organic matter
content, a K-value can be estimated from the range of values
ofthe last column of Table 15 .
Table 14 . Guidelines forestablishing soil erodibility classes
Soil
erodibility K-
Class potential value'
1 Negligible less
than
.15
2 Slight .15-.30
3 Moderately .30- .40
severe
4 Severe .40- .50
5 Very more
severe than
.50
Soil
Series
Drainage
Class
Soil characteristics
significant for
watererosion
Silt and very fine sand
4%organic matter
; very fine granular structure
; rapid permeability
Silt and very fine sand, 25-
40%;