Soils of the - Agriculture and Agri-Food Canada

Soils of the - Agriculture and Agri-Food Canada Soils of the - Agriculture and Agri-Food Canada

sis.agr.gc.ca
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MONROE SOILS Location and Extent : Monroe soils are common on the floodplain of the Fraser River east from th e confluence with the Pitt River. The largest areas are in Matsqui Valley and on Nicomen Island . About 110 ha of pure map units and 1290 ha of soil complexes dominated by Monroe soils are classified . The complexes are mostly with Fairfield, Matsqui and Page soils . Topography and Elevation : Monroe soils are mostly gently undulating or undulating, sometimes varying t o gently or moderately rolling . Slope gradients are less than 10 percent . The soils occupy the topographicall y higher landscape positions when in complexes with poorer drained soils . Elevations range from about 4 to 15 m above sea level . Parent Material and Texture : Monroe soils have developed from medium-textured, stone-free Fraser Rive r floodplain deposits that are more than 50 cm deep and overlie coarse-textured deposits, mainly sand . Surface and subsurface textures are usually silt loam, occasionally varying to fine sandy loam, loam or silty clay loam . The upper subsoil textures are similar but change at depth to sand or loamy sand, sometimes interstratified wit h thin, finer textured bands . Soil Moisture Characteristics : Monroe soils are moderately well to well drained . They are moderatel y pervious and have high water holding capacity and slow to moderate surface runoff . Temporary groundwate r tables may develop in the subsoil during the freshet period on the Fraser River or during heavy, prolonged rain . General Soil Description : Monroe soils generally have a grayish-brown, friable, cultivated silty surfac e about 20 cm thick which is underlain by about 15•cm of brown or brownish-gray, friable, weakly subangula r blocky to fine platy, partially leached, silty material . In turn, this is underlain by a dark brown to dark yellowis h brown, friable, moderately subangular blocky zone about 50 cm thick that is slightly enriched with eluviate d clay in the upper part and contains scattered clay flows and skins . It grades with increasing depth to loose san d or, sometimes, sand interspersed with thin, finer textured bands and contains few to common, brownish o r reddish mottles below about 100 cm . Casts and other evidence of earthworm activity are usually present in the upper 50 cm . Soil reactions vary from very strongly or strongly acid in the surface and grade to medium o r slightly acid at depth . Soil classification is Eluviated Eutric Brunisol . Commonly Associated Soils : Fairfield, Matsqui, Dewdney and Page soils are usually associated in th e undulating landscape with Monroe soils . Fairfield soils differ from Monroe soils by being imperfectly drained and usually lie in slightly lower landscape positions . Matsqui soils have textures similar to Monroe soils but th e underlying sand occurs within 20 to 50 cm of the surface ; Dewdney soils are similar to Matsqui soils an d additionally, are imperfectly drained . Page soils, generally depressional in relation to Monroe soils, are poorl y drained . Vegetation : Most Monroe soil areas are cleared and cultivated . The remaining, small, uncleared area s support, among others, black cottonwood, red alder, vine and bigleaf maple, birch, coast Douglas-fir, wester n red cedar, occasional Sitka spruce, blackberry, thimbleberry, salmonberry, and grass . Rooting is unrestricted to at least 100 cm depth . 136

(M) General Land Use Comments : (1) Monroe soils are well suited for most agricultural crops althoug h adverse topography may be somewhat limiting in a few areas . Irrigation is beneficial during dry summers t o maintain good production . If land levelling is undertaken, care should be taken to avoid exposing the sand y subsoil material since this will lower the soil's water holding capacity. A suggested method is to stockpile th e silty upper material, level the underlying sand, then spread the stockpiled soil . Monroe soils usually occupy relatively small, individual areas with convoluted boundaries making them difficult to manage as discrete units . (2) Monroe soils are among the better building sites on the Fraser River floodplain . The soils are relatively wel l drained although variable bearing strengths may require special foundation construction . Septic tanks usuall y function well. Where not dyked, Monroe soil areas are susceptible to flooding during the Fraser River freshe t period . (3) Monroe soils are well suited for the production of forest crops such as black cottonwood and dat a from a limited number of plots indicates this species potentially produces between 12 and 15 m 3/ha of wood pe r year. Production of black cottonwood and hybrid European poplars should be considered for relativel y inaccessible areas such as the islands in the Fraser River, or undyked areas susceptible to flooding . 137

(M)<br />

General L<strong>and</strong> Use Comments : (1) Monroe soils are well suited for most agricultural crops althoug h<br />

adverse topography may be somewhat limiting in a few areas . Irrigation is beneficial during dry summers t o<br />

maintain good production . If l<strong>and</strong> levelling is undertaken, care should be taken to avoid exposing <strong>the</strong> s<strong>and</strong> y<br />

subsoil material since this will lower <strong>the</strong> soil's water holding capacity. A suggested method is to stockpile th e<br />

silty upper material, level <strong>the</strong> underlying s<strong>and</strong>, <strong>the</strong>n spread <strong>the</strong> stockpiled soil . Monroe soils usually occupy<br />

relatively small, individual areas with convoluted boundaries making <strong>the</strong>m difficult to manage as discrete units .<br />

(2) Monroe soils are among <strong>the</strong> better building sites on <strong>the</strong> Fraser River floodplain . The soils are relatively wel l<br />

drained although variable bearing strengths may require special foundation construction . Septic tanks usuall y<br />

function well. Where not dyked, Monroe soil areas are susceptible to flooding during <strong>the</strong> Fraser River freshe t<br />

period . (3) Monroe soils are well suited for <strong>the</strong> production <strong>of</strong> forest crops such as black cottonwood <strong>and</strong> dat a<br />

from a limited number <strong>of</strong> plots indicates this species potentially produces between 12 <strong>and</strong> 15 m 3/ha <strong>of</strong> wood pe r<br />

year. Production <strong>of</strong> black cottonwood <strong>and</strong> hybrid European poplars should be considered for relativel y<br />

inaccessible areas such as <strong>the</strong> isl<strong>and</strong>s in <strong>the</strong> Fraser River, or undyked areas susceptible to flooding .<br />

137

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