|
LOGAN COUNTY, COLORADO 131
<br /> Weld Series underlain by mottled sand and gravel and deposited by
<br /> The Weld series consists of deep, well drained soils that the South Platte River. Westplain soils are on bottom-
<br /> formed in calcareous, eolian Ioamy materials. Weld soils lands and concave parts of low terraces. Slopes are 0 to 3
<br /> are on upland tablelands and have slopes of 0 to 3 per- 9inches,percent. verand to annual
<br /> mean precipannuaitation
<br /> range fris om
<br /> 13 to
<br /> 47
<br /> cent. Average annual precipitation ranges from 13 to 17 degrees F.
<br /> inches and the mean annual temperature is about 47 Westplain soils are near the Alda and Hayford soils.
<br /> degrees F. The Alda soils have mottled sand and gravel at depths of
<br /> Weld soils are similar to the Platner and Miff soils. 20 to 40 inches. The Hayford soils have B2t horizons and
<br /> They are near the Rago and Platner soils. Platner soils mottled sand and gravel at depths of 20 to 40 inches.
<br /> have B2t horizons with more than 15 percent fine sand or Atypical pedon of Westplain silty clay loam is located
<br /> coarser. Rago soils have dark colored surface layers ex- 70 feet north and 1,495 feet east of the west quarter
<br /> tending below 20 inches and buried subsoils. Iliff soils corner of section 7,T195 et ea
<br /> have bedrock at depths of less than 40 inches.
<br /> W.
<br /> A typical pedon of Weld loam is located 60 feet west All-0 to 8 inches, dark gray 00YR 4/1) heavy silty clay loam, black
<br /> and 130 feet south of the east quarter corner of section 7, (10YR 211) moist; moderate medium granular structure, slightly
<br /> T.8Iv., R.53W. hard, friable, sticky, plastic; calcareous, moderately alkaline (pH
<br /> 8.0);gradual wavy boundary.((;to 10 inches thick)
<br /> All-0 to 4 inches, grayish brown (lOYR 5/2) loam, very dark grayish Al2-8 to 14 inches;dark gray(10YR 411)heavy clay loam,black 0OYR
<br /> brown (10YR 3/2) moist; weak fine granular structure; soft, very 2/1) moist; weak medium subangular blocky structure, hard, firm,
<br /> friable; neutral (pH 7.0); clear smooth boundary (3 to 6 inches sticky and plastic; calcareous; moderately alkaline (pil 8.0), clear
<br /> thick) wavy boundary.(6 to 10 inches thick)
<br /> Al2 -4 to 7 inches, grayish brown (10YR 512) loam, eery dark grayish AC -14 to 17 inches; brown (10YR 513) very gravelly clan' loam, dark
<br /> brown 00YR 3/2) moist; weak coarse subangular blocky structure- brown (10YR 3/3) moist, with common medium distinct strong
<br /> hard,friable;neutral(pli 7.0);clear smooth boundary.(2 to 3 inches brown (7.5YR 5/6) mottles, massive, hard, friable; 50 percent
<br /> thick) gravel; calcareous;moderately alkaline (pH 7.9); abrupt wavy boun-
<br /> 1321t-7 to 10 inches; grayish brown (10YR 52) heavy silty clay loam, dary (0 to 6 inches thick)
<br /> very dark grayish brown (10YR 312) moist; moderate medium I1Cg-17 to 60 inches, light gray (10YR 7/2) very gravelly sand, light
<br /> prismatic parting to moderate medium subangular blocky structure, brownish gray(10YR 6/2)moist,with many large prominent strong
<br /> hard, firm; common thin clay films on faces of peds, and in root brown (7.5YR 5/6) mottles; single grained; louse dry and moist, 50
<br /> channels and pores,mildly alkaline(pH 7.2);clear smooth boundary. percent gravel;mildly alkaline(pH 7.6).
<br /> (3 to S inches thick) The mollic epipedon ranges from 7 to 20 inches thick. Depth to the
<br /> 1332t-10 to 16 inches; brown (10YR 5!3? heavy silty clay loam, dark sand and gravel substratum ranges from 14 to 20 inches These soils are
<br /> brown (10YR 3/3) moist; strong medium and fine prismatic parting calcareous in the upper part, but the substratum materials are com-
<br /> to strong fine angular blocky structure; very hard, firm; continuous monly noncaleareous.
<br /> thin clay films on faces of pods, in root channels and pores; mildly The A horizon has a color value of 4 or 5 dry,2 or 3 moist and chroma
<br /> alkaline(pH 7.4);clear smooth boundary. (4 to 8 inches thick) of 1 or 2.Texture of the A horizon is commonly a clay loam ranging to
<br /> 133ca-16 to 18 inches; light brownish gray (10YR 6/2) silty clay loam, silty clay loam or clay.
<br /> dark grayish brown (IOYR 412) moist; moderate medium prismatic
<br /> parting to moderate medium subangular blocky structure; hard,fri-
<br /> able; thin patchy clay films on faces of peds, in root channels and
<br /> pores: calcareous; moderately alkaline (pil 8.0), clear smooth boun-
<br /> dary. The system Of soil classification currently used was
<br /> (2 to 6 inches thick) y y
<br /> Clca-18 to 32 inches; light gray (2.5Y 7i2) loam, light brownish gray adopted by the National Cooperative Soil Survey in 1965.
<br /> (2.5Y 6/2)moist;massive,slightly hard,very friable;calcareous visi Readers interested in further details about the system
<br /> ble secondary calcium carbonate occurring as concretions and in thin should refer to the latest literature available (5).
<br /> seams and streaks; moderately alkaline(pH 8.4);clear smooth boun- The system of classification has silt categories.
<br /> ' dart' (8 to 24 inches thick) Beginning with the broadest, these
<br /> Cs -3: to at inches; light gray- (2.5Y7/2) fine sandy loam, grayish $� g categories are the
<br /> brown(2.5Y 5/2)moist, massive;slightly hard,very friable; calcare- order, suborder, great group, subgroup, family, and series.
<br /> ous;moderately alkaline(pH 5.4);gradual smooth boundary (s to 20 In this system the classification is based on the different
<br /> inches) soil properties that can be observed in the field or those
<br /> 0-41 to 60 inches; very pale brown GOYR 8/3) sandy loam, pale that can be inferred either from other properties that are
<br /> brown (10YR 61:3) moist; massive; soft, very friable; calcareous;
<br /> moderately alkaline(pH 8.4), observable in the field or from the combined data of soil
<br /> science and other disciplines. The properties selected for
<br /> Contrasting I1C horizons consisting of gravelly coarse sand can occur the higher categories are the result of soil genesis or of
<br /> below depths 4o inches. factors that affect soil genesis. In table 16 the soils of the
<br /> The A horizon
<br /> n has a color value of 4 or 5 dry, ° or 3 moist, and +
<br /> chroma of 2 or 3. It is commonly loam or very fine sandy loam.Texture survey area are classified according to the system.
<br /> of the B2t horizon includes clay loam,silty clay loam or clay. Texture of Categories of the system are discussed in the following
<br /> the C horizon is silt loam,loam,fine sandy loam or sandy loam. paragraphs.
<br /> Westplain Series ORDER. Ten soil orders are recognized as classes in
<br /> the system. The properties used to differentiate among
<br /> The Westplain series consists of deep, somewhat poorly orders are those that reflect the kind and degree of domi-
<br /> drained soils that formed in calcareous, clayey alluvium nant soil-forming processes that have taken place. Each
<br />
|