The Soils of The Regional Municipality of Ottawa=Carleton

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C values were calculated for common crops and management practices in the Ottawa-Carleton Region, and are presented inTable 17 . Field crops grown inthe area include canola, corn, forages, grain, peas, soybeans, white beans and winter wheat . The most common tillage practice is fall moldboard plowing (conventional tillage), with some chisel plowing and disking (reduced tillage) done as well . Underseeding or interseeding of the grain and wheat crops with forages are other practices being utilized . The lowest C values calculated for crops in the Ottawa- Carleton area were for forages (alfalfa, C = 0.02 ; red clover C = 0 .015) ; crops which tend to provide good cover throughout mostofthe year, reduce runoff, promote infiltration ofrainwater into the soil and the residuals of which can provide erosion resistance for up to two years after the meadow is replaced with other crops. This benefit is reflected in the lower C values for grain corn, one and two years after a meadow crop (C = 0.20 and 0 .34, respectively), as compared to a corn crop grown after other field crops and inexcess of twoyears after ameadow crop (C = 0 .37) . Grain corn (C = 0 .37), which leaves more residue on the surface after harvest than silage corn (C = 0 .50), also has a lower C value than the latter. The C value also indicates that soybeans in rotation (C = 0 .46) tend to resist erosion better than thosegrown continuously (C = 0 .54) or after similar, low residue-producing field crops . Fall tillage tends to expose the soil surface for a longer period of time than spring tillage. However the heavy texture of many of the Ottawa-Carleton soils does not make spring tillage practices feasible. The necessity of fall tilling can be compensated for, where possible, by reducing tillage operations so that more residue is left on the soil . For example, the soil conserving-benefits of reduced tillage are reflected in the C value for winter wheat after chisel plowing or disking as the only tillage (C = 0 .22) as compared to the same crop after moldboard plowing and disking (C = 0 .27) . Other practices which can help to control erosion include the inclusion of winter cover crops in a rotation, or underseeding crops to forage crops to provide some soil cover over the winter months (for example, C = 0 .41 for grain crops without underseeding, 0.36 for underseeding) . The above C values represent the potential soil loss reduction (compared to bare field condition) during a particular crop year. Crop rotation systems tend to have lower average annual Cvalues than continuous crops, as relatively high C values of some crops are offset by low values of others, when the values for all crops in the rotation are summed and divided by the total number ofcrop years in the system . Forexample, continuous silage corn has a C value of 0 .50, but if corn was rotated on a one year basis with a crop of a lesser C value (eg . grain after fall chiselling, C = 0.30) the average C value forthe two-year rotation would be 0.40 (0.50 + 0.30 / 2) . The introduction of a forage crop into the rotation (eg . alfalfa, C = 0 .02) has a beneficial effect duringthe duration of the meadow, and for up to two years after. A rotation of three years corn, one year fall-plowed grain would have a C value of 0.38 . Ifthree years of alfalfa (direct seeded the first year) were added to this rotation, the average annual C value would decrease to 0 .25, and if the alfalfa were underseeded in the grain the amount would be reduced even more to a C value of 0 .23 . The C factors presented in Table 17 provide an estimate of the erosion-controlling effectiveness of each crop . In practice, this effectiveness will vary depending on the given site condi tions and the quality ofmanagement . These general values can be used to estimate the effectiveness of existing, or alternative, 102 crop and management systems within the Ottawa-Carleton Region . (4) Soil Erosion Assessment Regional or site-specific assessment of soil erosion potential may be calculated using the quantitative relationships developed in the universal soil loss equation and information contained in this report . A graphical solution of the universal soil loss equation, in the form of a nomograph, is available for ease of computation . The soil loss nomograph provides a rapid method for assessing the effect of many land uses on soil loss potentials, for various soil and slope conditions. The following discussion illustrates how information contained in this section, and elsewhere in the soil report, may be used for predicting soil loss potentials on a regional basis . Regional SoilLoss Pbtential The soil maps of the Ottawa-Carleton Region provide delineations of soil, slope, and drainage conditions, at a scale of 1 :50,000 . Information contained in this section, with respect to soil erosion, can be used with information contained on the soil maps and legends to assess the relative erosion potential of most map unit delineations . Figure 36 illustrates part of a soil map and legend for the Ottawa-Carleton Region . Using Figure 36 as an example, the following discussion illustrates how interpretations of regional soil loss potential from erosion can bemade. 1 . In Figure 36, locate areas on the map for which the erosion potential is desired, and note the map unit symbol . For example, select soil map unit Gl/S1 .4, which represents 2 areas ofwelldrained soils of the Grenville soil association in Figure 36 . 2 . Go to the map legend and find the appropriate soil association - Grenville (G), and the appropriate soil landscape unit, ie. G 1 . Stoniness class (S 1) need not be directly considered . Slope Class (4) is noted . 3 . Determine the erodibility ofthe G 1 soil landscape unit from Table 13 . (Gl = 0 .31) 4 . Determine the topographic factors (L-S values) for Slope Class 4 (5-9%) from Table 16 . For example, use L = 100 m and S = 6%, thus LS = 1.22 . 5 . Using the soil loss prediction nomograph (Figure 37), locate the K and LS-values for the G 1/S 1 .4 map unit on the appropriateaxes (K = .31, LS = 1 .22) . Draw a line between theK and LS values to intersect the pivot line. Draw another line form the current or proposed land use through the point where the K-LS and the pivot lines intersect, to the soil loss potential axis . For example, ifcorn was the existing or proposed crop, the soil loss for the corn land use on G1/S1 .4 soil map unit would be approximately 14 t/ha, a moderately severe amount . Note that the G1 soil landscape unit has only one drainage component, ie. well or good . Many soil landscape units have two drainage components or classes . G4 soils, for example, are dominantly well drained with significant proportions of imperfectly drained soils . These two components have separate erodibility values, both of which should be considered in an erosion assessment . In addition to this, many soil map unit symbols contain two soil landscape units from different soil associations . In these cases, the K-value of each drainage class of each soil landscape unit should be noted and assessed according to its relative proportion in the soil landscape . (See section on MappingSystem .) 6 . Repeat interpretations for other map unit symbols in interest to gain a regional perspective of the potential soil erosion loss .
SOIL SOIL MATERIAL DESCRIPTION MAIN SURFACE SOIL LANDSCAPE DRAINAGE ASSOCIATION TEXTURE UNIT Dominant Significant Grenville Alkaline, stony, sandy loam, fine sandy loam, G1 Good (G) sandy loam, loam or silt loam loam, silt loam G2 Imperfect G3 Poor G4 Good Imperfect G5 Imperfect Poor G6 Very poor STONINESS CLASSES SLOPE CLASSES Class Percent stones on surface Class Percent S1 0 .01-0 .1 4 5-9 Figure 36 . An erosion potential classification system has been developed to quantify potential soil erosion losses into a five-class system, ranging from negligible to very severe (Table 18) . Results derived form the soil loss potential can be assessed, using Table 18, to determine whether unacceptable losses occur. If so, the crops or conservation measures that would be most appropriate to reduce erosion can be determined . Portion of a soil map and legend for the Ottawa-Carleton Region . The potential soil loss, calculated in this way, provides a Table 18 . Guidelines for assessing soil erosion potential classes general estimate ofthe potential erosion for a region . However, if the regional estimate is applied to specific fields, differences will exist because the regional information lacks the accuracy of a site-specific assessment . Soil erosion class Soil erosion potential t/ha/yr soil loss 1 Negligible (< 6) 2 Slight (6-11) 3 Moderately Severe (11-22) 4 Severe (22-33) 5 Very Severe (>33)
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i The Soils of The III Regional Mun
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ACKNOWLEDGEMENTS . . . . . . . . .
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1 . Soil map index for the Regional
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0 t W. CARLETO 10 L 20 km KANATA GO
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Otta!~? Figure 3. Main towns, trans
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Arnprior Chats Falls Almonte " Carp
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may also contain shaly layers . Out
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Till plains (undrumlinized) _ Esker
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Surficial Geology and Relationship
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HUN nnnnoioion miammoo nonmmnon nou
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GEOLOGICAL MATERIALS SOIL ASSOCIATI
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GEOLOGICAL MATERIALS SOIL ASSOCIATI
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In this survey, boundaries were per
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BASIC LAND AREAS SOIL ASSOCIATION -
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their agricultural use . The domina
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OTTAWA- CARLETON SOILS t TYPE DEPTH
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B3 : Dominantlyvery Rego Gleysols p
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cant component, approximately 600 h
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In some soils, significant layers o
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Taxonomic Components The well-drain
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Taxonomic Components Four component
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Correlation to Ottawa Urban Fringe
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The well-drained Orthic Melanic Bru
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ial which extends in a northwest-so
Page 51 and 52: all Leitrim soils classified as suc
Page 53 and 54: The imperfectly drained St . Damase
Page 55 and 56: Recognized Recognized Subgroups Ser
Page 57 and 58: Soil Materials North Gower soils co
Page 59 and 60: Figure 17 . A poorly drained Orthic
Page 61 and 62: Figure 25 . Manotick association so
Page 63 and 64: Soil Landscape Units Four units wer
Page 67 and 68: sloping areas, groundwater flow, an
Page 69 and 70: from clay to silty clay loam . In s
Page 73 and 74: scapes occurring inclose proximity
Page 75 and 76: Within Rockland units, significant
Page 77 and 78: A . AGRICULTURAL CAPABILITY CLASSIF
Page 79 and 80: Table 7 . (cont'd) R' : T' : V' : W
Page 81 and 82: adequate moisture or a wetness limi
Page 83 and 84: In order to apply the tables, one m
Page 85 and 86: (e) The Capability Rating Tables Ta
Page 87 and 88: 00 Table 9. (continued) Slope Class
Page 89 and 90: Table 9 . (continued) AGRICULTURAL
Page 91 and 92: Table 9 . (continued) AGRICULTURAL
Page 93 and 94: Soil Landscape Unit Table 10 . Agri
Page 95 and 96: The water erosion formula, A= RKLSC
Page 97 and 98: soil Association Table 13 . K-value
Page 99 and 100: graphic regions . Therefore, the C
Page 101: Table 17 . continued Crop Rotation
Page 105 and 106: C . LAND SUITABILITY CLASSIFICATION
Page 107 and 108: Table 19 . Land suitability ratings
Page 109 and 110: Table 19 . continued Soil associati
Page 111 and 112: 1 . Marshall, I.B., J. Dumanski, E.
Page 113 and 114: Class Description Sl Slightly stony
Page 115 and 116: Soil Association GRENVILLE Series a
Page 117 and 118: Soil Association Series and (Subgro
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The Soils of The Regional Municipality of Ottawa=Carleton

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