HomeMy WebLinkAbout20050578.tiff soil survey of
Weld County, Colorado
Southern Port
United States Department of Agriculture
Soil Conservation Service
in cooperation with
Colorado Agricultural Experiment Station
2005-0578
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Index to soil map units
Page Page
1—Altvan loam, 0 to 1 percent slopes 7 42—Nunn clay loam, 1 to 3 percent slopes 29
2—Altvan loam, 1 to 3 percent slopes 8 43—Nunn loamy sand, 0 to 1 percent slopes 29
3—Aquolls and Aquents, gravelly substratum 8 44—Olney loamy sand, 1 to 3 percent slopes 30
4—Aquolls and Aquepts, flooded 8 45—Olney loamy sand, 3 to 5 percent slopes 31
5—Ascalon sandy loam, 1 to 3 percent slopes 9 46—Olney fine sandy loam, 0 to 1 percent slopes 31
6—Ascalon sandy loam, 3 to 5 percent slopes 9 47—Olney fine sandy loam, 1 to 3 percent slopes 32
7—Ascalon sandy loam, 5 to 9 percent slopes 10 48—Olney fine sandy loam, 3 to 5 percent slopes 32
8—Ascalon loam, 0 to 1 percent slopes 11 49—Osgood sand, 0 to 3 percent slopes 33
9—Ascalon loam, 1 to 3 percent slopes 11 50—Otero sandy loam, 0 to 1 percent slopes 34
10—Bankard sandy loam, 0 to 3 percent slopes 12 51—Otero sandy loam, 1 to 3 percent slopes 34
11—Bresser sandy loam, 0 to 1 percent slopes 12 52—Otero sandy loam, 3 to 5 percent slopes 35
12—Bresser sandy loam, 1 to 3 percent slopes 13 53—Otero sandy loam, 5 to 9 percent slopes 35
13—Cascajo gravelly sandy loam, 5 to 20 percent 54—Paoli loam, 0 to 1 percent slopes 36
slopes 13 55—Paoli loam, 1 to 3 percent slopes 37
14—Colby loam, 0 to 1 percent slopes 13 56—Renohill clay loam, 0 to 3 percent slopes 37
15—Colby loam, 1 to 3 percent slopes 14 57—Renohill clay loam, 3 to 9 percent slopes 38
16—Colby loam, 3 to 5 percent slopes 14 58—Shingle loam, 1 to 3 percent slopes 38
17—Colby loam, 5 to 9 percent slopes 15 59—Shingle loam, 3 to 9 percent slopes 89
18—Colby-Adena loams, 3 to 9 percent slopes 16 60—Shingle-Renohill complex, 3 to 9 percent slopes 39
19—Colombo clay loam, 0 to 1 percent slopes 16 61—Tassel fine sandy loam, 5 to 20 percent slopes.... 40
20—Colombo clay loam, 1 to 3 percent slopes 16 62—Terry fine sandy loam, 0 to 3 percent slopes 40
21—Dacono clay loam, 0 to 1 percent slopes 17 63—Terry fine sandy loam, 3 to 9 percent slopes 41
22—Dacono clay loam, 1 to 3 percent slopes 18 64—Thedalund loam, 1 to 3 percent slopes 41
Fort Collins loam, 0 to 1 percent slopes 18 65—Thedalund loam, 3 to 9 percent slopes 42
—Fort Collins loam, 1 to 3 percent slopes 19 66—Ulm clay loam, 0 to 3 percent slopes 43
..o—Haverson loam, 0 to 1 percent slopes 19 67—Ulm clay loam, 3 to 5 percent slopes 43
26—Haverson loam, 1 to 3 percent slopes 20 68—Ustic Torriorthents, moderately steep 44
27—Heldt silty clay, 1 to 3 percent slopes 20 69—Valent sand, 0 to 3 percent slopes 44
28—Heldt silty clay, 3 to 5 percent slopes 21 70—Valent sand, 3 to 9 percent slopes 45
29—Julesburg sandy loam, 0 to 1 percent slopes 21 71—Valent-Loup complex, 0 to 9 percent slopes 45
30—Julesburg sandy loam, 1 to 3 percent slopes........ 22 72—Vona loamy sand, 0 to 3 percent slopes 46
31—Kim loam, 0 to 1 percent slopes 22 73—Vona loamy sand, 3 to 5 percent slopes 47
32—Kim loam, 1 to 3 percent slopes 23 74—Vona loamy sand, 5 to 9 percent slopes 47
33—Kim loam, 3 to 5 percent slopes 23 75—Vona sandy loam, 0 to 1 percent slopes 48
34—Kim loam, 5 to 9 percent slopes 24 76—Vona sandy loam, 1 to 3 percent slopes 48
35—Loup-Boel loamy sands, 0 to 3 percent slopes .... 25 77—Vona sandy loam, 3 to 5 percent slopes 49
36—Midway-Shingle complex, 5 to 20 percent slopes 25 78—Weld loam, 0,to 1 percent slopes 49
37—Nelson fine sandy loam, 0 to 3 percent slopes.... 26 79—Weld loam, 1 to 3 percent slopes 50
38—Nelson fine sandy loam, 3 to 9 percent slopes.... 26 80—Weld loam, 3 to 5 percent slopes 50
39—Nunn loam, 0 to 1 percent slopes 27 81—Wiley-Colby complex, 0 to 1 percent slopes.. 51
40—Nunn loam, 1 to 3 percent slopes 28 82—Wiley-Colby complex, 1 to 3 percent slopes.. 52
41—Nunn clay loam, 0 to 1 percent slopes 28 83—Wiley-Colby complex, 3 to 5 percent elopes 52
iv
8 SOIL SURVEY
filter the leachate. Sewage lagoons require sealing. 60 percent of the unit. Aquents, which have a lighter
.---Lawns, shrubs, and trees grow well. Capability subclass colored surface layer, make up about 35 percent. About 5
Is irrigated. percent is Aquepts and Bankard sandy loam.
2—Altvan loam, 1 to 3 percent slopes. This is a deep, These are deep, poorly drained soils that formed in
well drained soil on terraces at elevations of 4,500 to 4,900 recent alluvium. No one pedon is typical. Commonly the
feet. It formed in old alluvium deposited by the major soils have a mottled, mildly alkaline to moderately al-
rivers. Included in mapping are small areas of soils that kaline loamy or clayey surface layer and underlying
show evidence of poor drainage. Also included are small, material and are underlain by sand or sand and gravel
long and narrow areas of sand and gravel deposits. within 48 inches. In places they have a gleyed layer in the
Typically the surface layer of this Altvan soil is grayish underlying material.
brown loam about 10 inches thick. The subsoil is brown Most of the acreage is subject to flooding. The water
and light yellowish brown clay loam and sandy clay loam table is at or near the surface early in spring and recedes
about 14 inches thick. The substratum is calcareous loamy to as deep as 48 inches late in fall in some years.
sand about 5 inches thick over gravelly sand. These soils are used for rangeland and wildlife habitat.
Permeability and available water capacity are Some small areas have been reclaimed by major drainage
moderate. The effective rooting depth is 20 to 40 inches. and leveling and are used for irrigated crops.
Surface runoff is medium, and the erosion hazard is low. The potential native vegetation is dominated by alkali
This soil is used almost entirely for irrigated crops. It sacaton, switchgrass, and western wheatgrass. Saltgrass,
is suited to all crops commonly grown in the area, includ- sedge, rush, and alkali bluegrass are also prominent.
ing corn, sugar beets, beans, alfalfa, small grain, potatoes, Potential production ranges from 3,000 pounds per acre in
and onions. An example of a suitable cropping system is 3 favorable years to 2,000 pounds in unfavorable years. As
to 4 years of alfalfa followed by corn, corn for silage, range condition deteriorates, the switchgrass, alkali
sugar beets, small grain, or beans. Land leveling, ditch sacaton, and western wheatgrass decrease and saltgrass,
lining, and installing pipelines may be needed for proper sedge, and rush increase. gr gras
water application. Management of vegetation should be based on taking
All methods of irrigation are suitable, but furrow ir-
half and leaving half of the total annual production. Seed-
rigation is the most common. Barnyard manure and com-
ing is difficult and costly because numerous tillage prac-
mercial fertilizer are needed for top yields.
Windbreaks and environmental plantins of trees and tices are required to eliminate the saltgrass sod.
�'^. Switchgrass, western wheatgrass, alkali sacaton, tall
'limbs commonly grown in the area are generally well
,,uited to this soil. Cultivation to control competing wheatgrass, and tall fescue are suitable for seeding. They
vegetation should be continued for as many years as can be seeded into a clean, firm seedbed. Seedbed
possible following planting. Trees that are best suited and preparation usually requires more than 1 year to
have good survival are Rocky Mountain juniper, eastern eliminate the saltgrass sod. A grass drill should be used.
redcedar, ponderosa pine, Siberian elm, Russian-olive, and Seeding early in spring has proven most successful.
Wetland wildlife, especially waterfowl, utilize this unit.
hackberry. The shrubs best suited are skunkbush sumac,
lilac, Siberian peashrub, and American plum. The wetland plants provide nesting and protective cover,
This soil can produce habitat elements that are highly as well as some food. The nearby irrigated cropland,
suitable for openland wildlife including pheasant, cotton- where wildlife obtain much of their food and fmd protec-
tail, and mourning dove. Such crops as wheat, corn, and tive cover, makes this unit valuable to both wetland and
alfalfa provide suitable habitat for openland wildlife, openland wildlife.
especially pheasant. Tree and shrub plantings and Openland wildlife, especially pheasant, use this unit for
undisturbed nesting cover would enhance openland wil- cover and nesting. Deer find excellent cover in some
dlife populations. areas.
This Altvan soil has fair to good potential for urban These valuable wildlife areas should be protected from
and recreational development. The chief limiting soil fea- fire and fenced to prevent encroachment and overuse by
tures for urban development are the shrink-swell poten- livestock. They should not be drained.
tial of the subsoil as it wets and dries and the rapid These soils have good potential as a source of sand and
permeability of the sand and gravel substratum. Septic gravel. Capability subclass VIw; Salt Meadow range site.
tank absorption fields function properly, but in places the 4—Aquolls and Aquepts, flooded. This nearly level
substratum does not contain enough fines to properly map unit is in depressions in smooth plains and along the
filter the leachate. Sewage lagoons require sealing. bottoms of natural drainageways throughout the survey
Lawns, shrubs, and trees grow well. Capability subclass area. Aquolls, which have a dark colored surface layer,
IIe irrigated. make up about 55 percent of the unit. Aquepts, which
3—Aquolls and Aquents, gravelly substratum. This have a lighter colored surface layer, make up about 25
nearly level map unit is on bottom lands and flood plains percent. About 20 percent is soils that are well drained
all the major streams in the survey area. Aquolls, and soils that have sandstone or shale within 48 inches of
which have a dark colored surface layer, make up about the surface.
WELD COUNTY, COLORADO, SOUTHERN PART 9
These are deep, poorly drained soils that formed in If summer fallowed in alternate years, this soil is well
'^recent alluvium. No one pedon is typical. Commonly the suited to winter wheat, barley, and sorghum. Winter
Ails have a mottled, mildly to moderately alkaline loamy wheat is the principal crop. The predicted average yield is
or clayey surface layer and underlying material that ex- 33 bushels per acre. If the crop is winterkilled, spring
tends to a depth of 60 inches or more. In places they have wheat can be seeded. Generally precipitation is too low
a gleyed layer in the underlying material. for beneficial use of fertilizer.
Most of the acreage is subject to excessive runoff. The Stubble mulch farming, striperopping, and minimum til-
water table is at or near the surface in spring and during lage are needed to control soil blowing and water erosion.
the peak of the irrigation season. Terracing also may be needed to control water erosion.
These soils are used for rangeland and wildlife habitat. The potential native vegetation on this range site is
Some small areas are irrigated pasture. dominated by sand bluestem, sand reedgrass, and blue
The potential native vegetation is dominated by grama. Needleandthread, switchgrass, sideoats grama,
switchgrass, prairie cordgrass, saltgrass, alkali sacaton, and western wheatgrass are also prominent. Potential
big bluestem, indiangrass, western wheatgrass, slender Production ranges from 2,200 pounds per acre in favora-
wheatgrass, sedge, and rush. Cattails and bullrush grow ble years to 1,800 pounds in unfavorable years. As range
in the swampy spots associated with these range sites. condition deteriorates, the sand bluestem, sand reedgrass,
Potential production ranges from 4,000 pounds per acre in and switchgrass decrease and blue grama, sand dropseed,
favorable years to 3,000 pounds in unfavorable years. As and sand sage increase. Annual weeds and grasses invade
range condition deteriorates, the tall and mid grasses the site as range condition becomes poorer.
decrease, production drops, and saltgrass, sedge, and rush Management of vegetation should be based on taking
increase. The farming and irrigation in adjacent areas has half and leaving half of the total annual production. Seed-
increased the amount of salts on much of the acreage. ing is desirable if the range is in poor condition. Sand
Management of vegetation on this soil should be based bluestem, sand reedgrass, switchgrass, sideoats grama,
on taking half and leaving half of the total annual produc- blue grama, pubescent wheatgrass, and crested wheat-
tion. Switchgrass, big bluestem, indiangrass, western grass are suitable for seeding. The grass selected should
meet the seasonal requirements of livestock. It can be
wheatgrass, pubescent wheatgrass, intermediate wheat-
grass, tall wheatgrass, and tall fescue are suitable for seeded into a clean, firm sorghum stubble, or it can be
seeding. The plants selected should met the seasonal drilled into a firm prepared seedbed. Seeding early in
r- spring has proven most successful.
requirements of livestock. For successful seeding, a firm
Windbreaks and environmental plantings are generally
prepared seedbed is needed. A grass drill should be used.
n most successful. Til- suited to this soil. Soil blowing, the principal hazard in
Seeding early in spring has pr,ve
establishing trees and shrubs, can be controlled by cul-
lage is needed to eliminate the undesirable vegetation. tivating only in the tree row and by leaving a strip of
Wetland wildlife, especially waterfowl, utilize this unit. vegetation between the rows. Supplemental irrigation
The wetland plants provide nesting and protective cover may be needed at the time of planting and during dry
as well as some food. The nearby irrigated cropland, periods. Trees that are best suited and have good survival
where wildlife obtain much of their food and find protec- are Rocky Mountain juniper, eastern redcedar, ponderosa
tive cover, makes this unit valuable to both wetland and pine, Siberian elm, Russian-olive, and hackberry. The
openland wildlife. shrubs best suited are skunkbush sumac, lilac, and Siberi-
Openland wildlife, especially pheasant, use this unit for an peashrub.
cover and nesting. Deer find excellent cover in some Wildlife is an important secondary use of this soil. The
areas. These valuable wildlife areas should be protected cropland areas provide favorable habitat for ring-necked
from fire and fenced to prevent encroachment and pheasant and mourning dove. Many nongame species can
overuse by livestock. They should not be drained. Capa- be attracted by establishing areas for nesting and escape
bility subclass VIw; Aquolls in Salt Meadow range site, cover. For pheasants, undisturbed nesting cover is essen-
Aquepts in Wet Meadow range site. tial and should be included in plans for habitat develop-
5—Ascalon sandy loam, 1 to 3 percent slopes. This is ment. Rangeland wildlife, for example, the pronghorn an-
a deep, well drained soil on uplands at elevations of 4,600 telope, can be attracted by developing livestock watering
to 5,200 feet. It formed in alluvium. Included in mapping facilities, managing livestock grazing, and reseeding
are small areas of rock outcrop. where needed.
Typically the surface layer is brown sandy loam about Few areas of this Ascalon soil are in major growth and
10 inches thick. The subsoil is pale brown and yellowish urbanized centers. The shrink-swell potential of the sub-
brown sandy clay loam about 15 inches thick. The sub- soil as it wets and dries is the most limiting soil feature
stratum to a depth of 60 inches is calcareous fine sandy that must be considered in planning homesites and con-
loam. structing roads. Capability subclass IIIe nonirrigated;
Permeability is moderate. Available water capacity is Sandy Plains range site.
high. The effective rooting depth is 60 inches or more. 6—Ascalon sandy loam, 3 to 5 percent slopes. This is
Surface runoff is slow, and the erosion hazard is low. a deep, well drained soil on uplands at elevations of 4,600
WELD COUNTY, COLORADO, SOUTHERN PART 15
rigating close grown crops and pasture. Furrows, contour of 4,850 to 5,050 feet. It formed in calcareous eolian
rnirrows, and cross slope furrows are suitable for row deposits. Included in mapping are small areas of soils that
-rops. Sprinkler irrigation is also desirable. Keeping til- have fine sandy loam or loam underlying material and
lage to a minimum and utilizing crop residue help to con- small areas of soils that are shallow to moderately deep
trol erosion. Maintaining fertility is important. Crops over shale and sandstone.
respond to applications of phosphorus and nitrogen. Typically the surface layer of this Colby soil is pale
In nonirrigated areas this soil is suited to winter wheat. brown loam about 7 inches thick. The underlying material
The predicted average yield is 28 bushels per acre. The is very pale brown silt loam to a depth of 60 inches.
soil is summer fallowed in alternate years to allow Permeability is moderate. Available water capacity is
moisture accumulation. Generally precipitation is too low high. The effective rooting depth is 60 inches or more.
for beneficial use of fertilizer. Surface runoff is rapid, and the erosion hazard is high.
Stubble mulch farming, striperopping, and minimum til- This soil is suited to limited cropping. Intensive
lage are needed to control soil blowing and water erosion. cropping is hazardous because of erosion. The cropping
Terracing also may be needed to control water erosion. system should be limited to close grown crops, such as al-
The potential native vegetation is dominated by blue falfa, wheat, and barley. This soil also is suited to ir-
grama. Several mid grasses, such as western wheatgrass rigated pasture. A suitable cropping system is 3 to 4
and needleandthread, are also present. Potential produc- years of alfalfa followed by 2 years of corn and small
tion ranges from 1,600 pounds per acre in favorable years grain and alfalfa seeded with a nurse crop.
to 1,000 pounds in unfavorable years. As range condition Close grown crops can be irrigated from closely spaced
deteriorates, the mid grasses decrease; blue grama, buf- contour ditches or sprinklers. Contour furrows or sprin-
falograss, snakeweed, yucca, and fringed sage increase; klers should be used for new crops. Applications of
and forage production drops. Undesirable weeds and an- nitrogen and phosphorus help in maintaining good produc-
nuals invade the site as range condition becomes poorer. tion.
Management of vegetation on this soil should be based The potential native vegetation is dominated by blue
on taking half and leaving half of the total annual produc- grama. Sideoats grama, little bluestem, western wheat-
tion. Seeding is desirable if the range is in poor condition. grass, and sedge are also prominent. Potential production
Sideoats grama, little bluestem, western wheatgrass, blue ranges from 1,800 pounds per acre in favorable years to
grama, pubescent wheatgrass, and crested wheatgrass are 1,500 pounds in unfavorable years. As range condition
suitable for seeding. The grass selected should meet the deteriorates, the sideoats grama and little bluestem
seasonal requirements of livestock. It can be seeded into decrease, forage production drops, and blue grama, butt clean, firm sorghum stubble, or it can be drilled into a falograss, and several perennial forbs and shrubs in-
firm prepared seedbed. Seeding early in spring has crease. Undesirable weeds and annuals invade the site as
proven most successful. range condition becomes poorer.
Windbreaks and environmental plantings of trees and Management should be based on taking half and leaving
shrubs commonly grown in the area are generally well half of the total annual production. Seeding is desirable if
suited to this soil. Cultivation to control competing the range is in poor condition. Sideoats grama, little
vegetation should be continued for as many years as bluestem, western wheatgrass, and pubescent wheatgrass
possible following planting. Trees that are best suited and are suitable for seeding. The grass selected should meet
have good survival are Rocky Mountain juniper, eastern the seasonal needs of livestock. It can be seeded into a
redcedar, ponderosa pine, Siberian elm, Russian-olive, and clean, firm sorghum stubble, or it can be drilled into a
hackberry. The shrubs best suited are skunkbush sumac, firm prepared seedbed. Plowing and drilling should be on
lilac, Siberian peashrub, and American plum. the contour to minimize runoff and soil losses. Seeding
Openland wildlife, such as pheasant, mourning dove, early in spring has proven most successful.
and cottontail, and rangeland wildlife, such as antelope, Windbreaks and environmental plantings of trees and
cottontail, and coyote, are best suited to this soil. Under shrubs commonly grown in the area are generally well
irrigation, good wildlife habitat can be established, suited to this soil. Cultivation to control competing
benefiting many kinds of openland wildlife. Forage vegetation should be continued for as many years as
production is typically low on rangeland, and grazing possible following planting. Trees that are best suited and
management is needed if livestock and wildlife share the have good survival are Rocky Mountain juniper, eastern
range. Livestock watering facilities also are utilized by redcedar, ponderosa pine, Siberian elm, Russian-olive, and
various wildlife species. hackberry. The shrubs best suited are skunkbush sumac,
This soil has good potential for urban and recreational lilac, Siberian peashrub, and American plum.
developments. Road design can be modified to compen- Openland wildlife, such as pheasant, mourning dove,
sate for the limited capacity of this soil to support a load. and cottontail, and rangeland wildlife, such as antelope,
Capability subclass IIIe irrigated, IVe nonirrigated; cottontail, and coyote, are best suited to this soil. Under
Loamy Plains range site. irrigation, good wildlife habitat can be established,
17—Colby loam, 5 to 9 percent slopes. This is a deep, benefiting many kinds of openland wildlife. Forage
well drained soil on upland hills and ridges at elevations production is typically low on rangeland, and grazing
16 SOIL SURVEY
management is needed if livestock and wildlife share the ments of livestock. It can be seeded into a clean, firm
range. Livestock watering facilities also are utilized by sorghum stubble, or it can be drilled into a firm prepared
^uious wildlife species. seedbed. Plowing and drilling should be on the contour to
This soil has good potential for urban and recreational minimize runoff and soil losses. Seeding early in spring
developments. Road design can be modified to compen- has proven most successsful. Capability subclass IVe
sate for the limited capacity of this soil to support a load. nonirrigated; Colby soil in Loamy Slopes range site,
Capability subclass IVe irrigated, VIe nonirrigated; Adena soil in Loamy Plains range site.
Loamy Slopes range site. 19—Colombo clay loam, 0 to 1
18—Colby-Adena loams, 3 to 9 percent percent slopes. This is
slopes. These a deep, well drained soil on flood plains and terraces at
gently sloping to moderately sloping soils are on plains, elevations of 4,600 to 4,780 feet. It formed in stratified
hills, and ridges at elevations of 4,750 to 4,900 feet. The calcareous alluvium. Included in mapping are small areas
Colby soil, which makes up about 55 percent of the map of soils that have a loam surface layer and some small
unit, occupies the steeper, convex parts of the landscape. leveled areas.
The Adena soil, about 30 percent of the unit, occupies the Typically the surface layer of this Colombo soil is dark
less steep, slightly concave parts. About 15 percent is grayish brown clay loam about 14 inches thick. The upper
Kim loam and Weld loam. 7 inches of the underlying material is pale brown
The Colby soil is deep and well drained. It formed in stratified clay loam and loam. The lower part to a depth
calcareous eolian deposits. Typically the surface layer is of 60 inches is very pale brown loam stratified with thin
pale brown loam about 7 inches thick. The underlying lenses of fine sand, medium sand, and clay loam.
material to a depth of 60 inches is very pale brown silt Permeability is moderate. Available water capacity is
loam. high. The effective rooting depth is 60 inches or more.
Permeability is moderate. Available water capacity is Surface runoff is slow, and the erosion hazard is low.
high. The effective rooting depth is 60 inches or more. In irrigated areas this soil is suited to crops commonly
Surface runoff is rapid, and the erosion hazard is high. grown in the area, such as corn, sugar beets, beans, alfal-
The Adena soil also is deep and well drained and fa, onions, and potatoes.
formed in calcareous eolian deposits. Typically the surface All methods of irrigation that are common to the area
layer is brown loam about 6 inches thick. The subsoil is are used. Borders are suitable for small grain, alfalfa, and
brown and very pale brown clay loam about 3 inches pasture. Furrow irrigation is used for row crops. Crops
thick. The substratum to a depth of 60 inches is very pale respond to application of nitrogen and phosphorus.
,3(own silt loam. Windbreaks and environmental plantings of trees and
'ermeability is slow. Available water capacity is high. shrubs commonly grown in the area are generally well
mile effective rooting depth is 60 inches or more. Surface suited to this soil. Cultivation to control competing
runoff is medium, and the erosion hazard is moderate. vegetation should be continued for as many years as
This unit is used for nonirrigated cropland and range- possible following planting. Trees that are best suited and
land. It is suited to winter wheat, barley, and sorghum. have good survival are Rocky Mountain juniper, eastern
Most of the acreage is planted to winter wheat and is redcedar, ponderosa pine, Siberian elm, Russian-olive, and
summer fallowed in alternate years to allow moisture ac- hackberry. The shrubs best suited are skunkbush sumac,
cumulation. Generally precipitation is too low for benefi- lilac, Siberian peashrub, and American plum.
cial use of fertilizer. Wildlife is an important secondary use of this soil.
Stubble mulch fanning, striperopping, and minimum til- Ring-necked pheasant, mourning dove, and many non-
lage are needed to control soil blowing and water erosion. game species can be attracted by establishing areas for
Terracing also may be needed to control water erosion. nesting and escape cover. For pheasants, undisturbed
The potential native vegetation on this unit is nesting cover is essential and should be included in plans
dominated by blue grama. Sideoats grama, little bluestem, for habitat development, especially in areas of intensive
and western wheatgrass are also prominent. Potential agriculture.
production ranges from 1,800 pounds per acre in favora- Where this soil is on flood plains and is susceptible to
ble years to 1,100 pounds in unfavorable years. As range flooding it has poor potential for urban and recreational
condition deteriorates, the sideoats grama and little development. On the higher terraces the potential is fair.
bluestem decrease, forage production drops, and blue Dwelling and road designs need to be modified to in-
grama, buffalograss, and several perennial forbs and crease the capacity of the soil to support a load and to
shrubs increase. Undesirable weeds and annuals invade protect it against frost action. Capability subclass IIw ir-
the site as range condition becomes poorer. rigated.
Management should be based on taking half and leaving 20—Colombo clay loam, 1 to 3 percent slopes. This is
half of the total annual production. Seeding is desirable if a deep, well drained soil on flood plains and terraces at
the range is in poor condition. Sideoats grama, little elevations of 4,600 and 4,780 feet. It formed in stratified
bluestem, western wheatgrass, bluegrama, pubescent calcareous alluvium. Included in mapping are small areas
wheatgrass, and crested wheatgrass are suitable for seed- of soils that have a loam surface layer. Some small
The grass selected should meet the seasonal require- leveled areas are also included.
52 SOIL SURVEY
the limited capacity of this soil to support a load. Capa- Management of vegetation on this soil should be based
., bility class I irrigated. on taking half and leaving half of the total annual produc-
82—Wiley-Colby complex, 1 to 3 percent slopes. This tion. Seeding is desirable if the range is in poor condition.
nearly level map unit is on smooth plains in the western Sideoats grama, little bluestem, western wheatgrass, blue
part of the survey area at elevations of 4,850 to 5,000 grama, pubescent wheatgrass, and crested wheatgrass are
feet. The Wiley soil makes up about 60 percent of the suitable for seeding. The grass selected should meet the
unit, and the Colby soil about 30 percent. About 10 per- seasonal requirements of livestock. It can be seeded into
cent is Heldt silty clay and Weld loam. a clean, firm sorghum stubble or it can be drilled into a
The Wiley soil is deep and well drained. It formed in firm prepared seedbed. Seeding early in spring has
calcareous eolian deposits. Typically the surface layer is proven most successful.
pale brown silt loam about 11 inches thick. The subsoil is Windbreaks and environmental plantings are generally
pale brown silty clay loam about 23 inches thick. The sub- well suited to these soils. Cultivation to control competing
stratum to a depth of 60 inches is very pale brown silty vegetation should be continued for as many years as
clay loam. possible following planting. Trees that are best suited and
Permeability is moderately slow. Available water have good survival are Rocky Mountain juniper, eastern
capacity is high. The effective rooting depth is 60 inches redcedar, ponderosa pine, Siberian elm, Russian-olive, and
or more. Surface runoff is medium, and the erosion hackberry. The shrubs best suited are skunkbush sumac,
hazard is moderate. lilac, Siberian peashrub, and American plum.
The Colby soil also is deep and well drained and formed Openland wildlife, such as pheasant, mourning dove,
in calcareous eolian deposits. Typically the surface layer and cottontail are best suited to these soils. Wildlife
is pale brown loam about 7 inches thick. The underlying habitat development, including tree and shrub plantings
material is very pale brown silt loam to a depth of 60 and grass plantings to serve as nesting areas, should be
inches. successful without irrigation during most years. Under ir-
Permeability is moderate. Available water capacity is rigation, good wildlife habitat can be established, benefit-
high. The effective rooting depth is 60 inches or more. ing many kinds of openland wildlife.
Surface runoff is medium, and the erosion hazard is The Wiley soil has only fair potential for urban and
moderate. recreational development. Slow permeability, moderate
This map unit is used for irrigated and nonirrigated shrink-swell potential, and limited bearing capacity cause
cropland and for rangeland, wildlife habitat, and urban problems in dwelling and road construction. The Colby
r development. soil has good potential for urban and recreational develop-
In irrigated areas these soils are suited to all crops ment. Road design can be modified to compensate for the
commonly grown in the area, including corn, sugar beets, limited capacity of this soil to support a load. Capability
beans, alfalfa, small grain, and onions. An example of a subclass Ile irrigated, IVe nonirrigated; Loamy Plains
suitable cropping system is 3 to 4 years of alfalfa fol- range site.
lowed by corn, corn for silage, sugar beets, small grain, or 83—Wiley-Colby complex, 3 to 5 percent slopes. This
beans. Land leveling, ditch lining, and installing pipelines gently sloping map unit is on plains at elevations of 4,850
may be needed for proper water applications. to 5,000 feet. The Wiley soil makes up about 60 percent of
All methods of irrigation are suitable, but furrow ir- the unit, and the Colby soil about 30 percent. About 10
rigation is the most common. Barnyard manure and com- percent is Heldt silty clay and Weld loam.
mercial fertilizer are needed for top yields. The Wiley soil is deep and well drained. It formed in
In nonirrigated areas these soils are suited to winter calcareous eolian deposits. Typically the surface layer is
wheat, barley, and sorghum. Most of the acreage is pale brown silt loam about 11 inches thick. The subsoil is
planted to winter wheat. The predicted average yield is pale brown silty clay loam about 23 inches thick. The sub-
28 bushels per acre. The soil is summer fallowed in al- stratum to a depth of 60 inches is very pale brown silty
ternate years to allow moisture accumulation. Generally clay loam.
precipitation is too low for beneficial use of fertilizer. Permeability is moderately slow. Available water
Stubble mulch farming, striperopping, and minimum til- capacity is high. The effective rooting depth is 60 inches
lage are needed to control soil blowing and water erosion. or more. Surface runoff is medium to rapid, and the ero-
Terracing also may be needed to control water erosion. sion hazard is moderate.
The potential native vegetation is dominated by blue The Colby soil also is deep and well drained and formed
grama. Several mid grasses such as western wheatgrass in calcareous eolian deposits. Typically the surface layer
and needleandthread are also present. Potential produc- is pale brown loam about 7 inches thick. The underlying
tion ranges from 1,600 pounds per acre in favorable years material is very pale brown silt loam to a depth of 60
to 1,000 pounds in unfavorable years. As range condition inches.
deteriorates, the mid grasses decrease; blue grama, buf- Permeability is moderate. Available water capacity is
falograss, snakeweed, yucca and fringed sage increase; high. The effective rooting depth is 60 inches or more.
r.,,and forage production drops. Undesirable weeds and an- Surface runoff is medium to rapid, and the erosion hazard
nuals invade the site as range condition becomes poorer. is moderate.
i
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WELD COUNTY, COLORADO, SOUTHERN PART 53
This unit is used for irrigated and nonirrigated The Wiley soil has only fair potential for urban and
vland and for rangeland, wildlife habitat, and urban recreational development. Slow permeability, moderate
svelopment. shrink-swell potential, and limited bearing capacity cause
In irrigated areas these soils are suited to the crops problems in dwelling and road construction. The Colby
commonly grown in the area. Perennial grasses and alfal- soil has good potential for urban and recreational develop-
fa or close grown crops should be grown at least 50 per- ments. Road design can be modified to compensate for
cent of the time. Contour ditches and corrugations can be the limited capacity of this soil to support a load. Capa-
used in irrigating close grown crops and pasture. Fur- bility subclass IIIe irrigated, IVe nonirrigated; Loamy
rows, contour furrows, and cross slope furrows are suita- Plains range site.
ble for row crops. Sprinkler irrigation is also desirable.
Keeping tillage to a minimum and utilizing crop residue Use and management of the soils
help to control erosion. Maintaining fertility is important.
Crops respond to applications of phosphorus and nitrogen. The soil survey is a detailed inventory and evaluation
In nonirrigated areas these soils are suited to winter of the most basic resource of the survey area—the soil. It
wheat, barley, and sorghum. Most of the acreage is is useful in adjusting land use, including urbanization, to
planted to winter wheat. The predicted average yield is the limitations and potentials of natural resources and the
28 bushels per acre. The soil is summer fallowed in al- environment. Also, it can help avoid soil-related failures
ternate years to allow moisture accumulation. Generally in uses of the land.
precipitation is too low for beneficial use of fertilizer. While a soil survey is in progress, soil scientists, con-
Stubble mulch farming, striperopping, and minimum til- servationists, engineers, and others keep extensive notes
lage are needed to control soil blowing and water erosion. about the nature of the soils and about unique aspects of
Terracing also may be needed to control water erosion. behavior of the soils. These notes include data on erosion,
The potential native vegetation is dominated by blue drought damage to specific crops, yield estimates, flood-
grama. Several mid grasses, such as western wheatgrass ing, the functioning of septic tank disposal systems, and
and needleandthread, are also present. Potential produc- other factors affecting the productivity, potential, and
tion ranges from 1,600 pounds per acre in favorable years limitations of the soils under various uses and manage-
to 1,000 pounds in unfavorable years. As range condition ment. In this way, field experience and measured data on
deteriorates, the mid grasses decrease; blue grama, buf- soil properties and performance are used as a basis for
.^^lograss, snakeweed, yucca, and fringed sage increase; predicting soil behavior.
.d forage production drops. Undesirable weeds and an- Information in this section is useful in planning use and
nuals invade the site as range condition becomes poorer. management of soils for crops, pasture, and rangeland, as
Management of vegetation on these soils should be sites for buildings, highways and other transportation
based on taking half and leaving half of the total annual systems, sanitary facilities, and parks and other recrea-
production. Seeding is desirable if the range is in poor tion facilities, and for wildlife habitat. From the data
condition. Sideoats grama, little bluestem, western wheat- presented, the potential of each soil for specified land
grass, blue grama, pubescent wheatgrass, and crested uses can be determined, soil limitations to these land uses
wheatgrass are suitable for seeding. The grass selected can be identified, and costly failures in houses and other
should meet the seasonal requirements of livestock. It can structures, caused by unfavorable soil properties, can be
be seeded into a clean, firm sorghum stubble, or it can be avoided. A site where soil properties are favorable can be
drilled into a firm prepared seedbed. Seeding early in selected, or practices that will overcome the soil limita-
spring has proven most successful. tions can be planned.
Windbreaks and environmental plantings of trees and Planners and others using the soil survey can evaluate
shrubs commonly grown in the area are generally well the impact of specific land uses on the overall productivi-
ty of the survey area or other broad planning area and on
suited to these soils. Cultivation to control competing
vegetation should be continued for as many years as the environment. Productivity and the environment are
closely related to the nature of the soil. Plans should
possible following plantings. Trees that are best suited maintain or create a land-use pattern in harmony with the
and have good survival are Rocky Mountain juniper, east- natural soil.
ern redcedar, ponderosa pine, Siberian elm, Russian-olive, Contractors can find information that is useful in locat-
and hackberry. The shrubs best suited are skunkbush ing sources of sand and gravel, roadfill, and topsoil. Other
sumac, lilac, Siberian peashrub, and American plum. information indicates the presence of bedrock, wetness, or
Openland wildlife, such as pheasant, mourning dove, very firm soil horizons that cause difficulty in excavation.
and cottontail, are best suited to these soils. Wildlife Health officials, highway officials, engineers, and many
habitat development, including tree and shrub plantings other specialists also can find useful information in this
and grass plantings to serve as nesting areas, should be soil survey. The safe disposal of wastes, for example, is
successful without irrigation during most years. Under ir- closely related to properties of the soil. Pavements, side-
'gation, good wildlife habitat can be established, benefit- walks, campsites, playgrounds, lawns, and trees and
.g many kinds of openland wildlife. shrubs are influenced by the nature of the soil.
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