|
<br />
<br />'r
<br />i
<br />
<br />i
<br />1
<br />~~
<br />
<br />
<br />r
<br />
<br />
<br />
<br />
<br />
<br />
<br />ARAPAHOE COUNTY, COLORADO
<br />In some places small slips or steps occur on the Thedahmd
<br />soil.
<br />1'crry sandy loam makes up 40 to 'b0 percent of this
<br />complex; Olney salxly loam, 20 to 30 percent; and
<br />'Phed;tlund sandy loam, 2l1 to 30 percent. Outcrops of
<br />sandstone make up alwut 10 percent of tho area mapped.
<br />Llclnded ttith these soils in mapping were small areas
<br />of Bast loam and of 'Passel sandy loam.
<br />Dlost of this complex is ramreland. Because the soils are
<br />steep and stn sc;terely susreptlble to erosion, they are not
<br />suited to cultivated crops. The few areas that wcl•e culti-
<br />cnted pace been severely eroded and, in plares,tLe subsoil
<br />has bclal exposed. \umerous gullies, G to 12 inches deep
<br />autl 2U to lU0 feet npart7 Lure formed. In most places, how-
<br />ever, the formmly cultnated accts have beml reseeded to
<br />grass. Uood range IniIll:LgC111P.11t, including remdation of
<br />gracing, is essential in contmllin4 erosion. (Capability
<br />unit Vle-3; Sandy Ylams range site; tree planting stlit-
<br />;tlrility group 4)
<br />Thedalund Series
<br />'1'hc. '1•hcdahunl series c•onsist~ of moderately deep,
<br />strongly sloping to stacp soils on uplands thrmlghmlt. the
<br />anmt.t. '1'hcse soils detclnped in material wcntLorcd from
<br />interlmddrd s;uulstrote and shale.
<br />In a t_}•picnl 1n•olile the surface layer is light olive-brown,
<br />nmlcalrnrrous light clay loam about 5 inches think. Belmv
<br />this is a layer of light olive-brown, stl•ongly c;drn l•eons
<br />li;.,•Lt clay lo;uu shoat 4 inches thick. The mu~et•lying m:l-
<br />terinl is cer}' strmtgly calc:unous and consists of light yel-
<br />lowisb-brotvnsilty clay loam to a depth of 13 inches alai of
<br />light yellowish-brmcu dI5111tegr:LtCd shale and s:unlstmle
<br />bcloa•. Consolidated shale that contains crystals and scams
<br />of gypsum nud strata of s:mdstone and siltstone are at a
<br />deptL of nbnnt.:-0 innc~s.
<br />'I'hn 'Thedalund wtils Lace moderate to rapid water in-
<br />t.uka :uRl IIIn11C1'i1tC :Ltad:LblO R'atOl' hOldlllg capacity, They
<br />are droughty, malerafo G+ low in natural fertility, and
<br />snsccptible fn sutcre tcnh~r erosion and soil blotting.
<br />'These soils are axed mainly for native pasture Because
<br />ul• drongldiness, law fertility, and the severe hazards of
<br />water erosion nud soil blowing, they are not suited to cul-
<br />tivated crops.
<br />'Pypical profilo of Thedalund clay loam, 9 to 20 percent
<br />slopes, S00 feet. east of the southwest corner of section 12,
<br />T. 5 S., It. 5S ~V.:
<br />Ally to 1 inch, light olive-brown (^_.5Y 5/3) light clay loam,
<br />olive brown (?.GY 4/4) when moist; weal:, medium,
<br />crumb structure [hat breaks to weak, medium, plntp
<br />stnlctnre; soft when dry, friable when waist; non-
<br />calcareous: abrupt, smooth boundary.
<br />Al?-1 to 5 inches, light olive-brown (2.5Y 5/4) light clay
<br />loam, olive brmvn (2.5Y 9/•9) when moist; weak,
<br />medium, prismatic stncture that breaks to w-eok,
<br />medium, subnngular blocky structure; slightly hard
<br />when dry, very friable when moist; novcalcareous;
<br />small, flat fragments of sandstone common; clear,
<br />smooth boundary.
<br />AC-5 to 9 inches, light olive-brown (2.5Y 5/4) ]fgbt clay loam,
<br />olive brown (2.5Y 4/9) when moist; weak, medium,
<br />prismatic structure that brd+ke to weak, medium, sub-
<br />angular blocky structure: slightly hard when dry,
<br />friable when moist; strongly calcareous; small, Bat
<br />fragments of sandstone common; clear, smooth
<br />boundary.
<br />29
<br />Clca-0 l0 13 inches, light yellotvish-broa•n (2.5Y 0/3) silty
<br />clay loam, light olive brown (2.SY 5!•1) when moist;
<br />x•eak, medium, prismatic structure; slightly Lard when
<br />dry, friable when moist; concretions of lime and
<br />mottles of iron; very strongly calcareous; more frag-
<br />ments oP sandstone tha^ i^ the AC horizon; clear,
<br />smooth boundary.
<br />- C2-13 to 30 inches, light yellowish-brown (2.5Y 6/4) disin-
<br />tegn[ed shale and sandsWne ;some concretions of imn
<br />and lime; very strongly calctreous.
<br />I;-30 inches }, cronsolida[ed shale containing crystals and
<br />seams of gypsum and straw oP sandstone and silt-
<br />stoue; strongly calcareous.
<br />The A horizon ranges from 2 to 5 inches iv thickness and
<br />from light clay loam to heavy sandy loam in texture. The C
<br />horizon is 15 to 35 inches thick. The texture or We strata wi this
<br />the C horizon ranges from clay loam to scud, but is generally
<br />loo m,
<br />The Thedalund soils contain more clay than the Terry soils,
<br />which have a B horizon. They are coarser textured, genernllp
<br />are deeper, and support more vegetatiml than Samsil soils.
<br />Thedalund clay loam, 9 to 20 percent slopes (ThEI.-
<br />This soil is on uplands, mainly in the c1.Gtern p:u t of the
<br />county along Badger Creek. Areas generally are less Lhan
<br />1G0 awes in sire. Hunofl' is rapid, water intake is moderate,
<br />and available roster holding capacity is moderate- This
<br />soil has the profile described ns typical for the series
<br />Included with this soil in mapping were a fete shall
<br />mess of Baca loam and of S:uusil clay, gypsum. Outcrops
<br />of barren, bard sandstone, less than 50 feet across, make up
<br />a mall percenGtgo of any :twat mapped.
<br />All of this soil is naWvc range. Some of the grasses at•e
<br />blue gralnn, western wLcatgruss, and needlegrw. Culki-
<br />vatetl clops are not suited, but a few fields have been
<br />cultivated vul then abandoned. These areas can he st~26t-
<br />lined by seeding grasses and controlling grazing. (Capa-
<br />bility amt VIo-] ;Loamy Slopes tangs stte; tree planting
<br />suitability group 5)
<br />Thedalund clay loam, 9 to 20 percent slopes, eroded
<br />IThE21•-This soil is mainly aloltg drainageways and in
<br />old ab:uuloned fields in the eastern part of the county. It
<br />occurs w•ithiu :uul adjacent. to areas of Thedalund clay
<br />loam, 0 to 20 percent slopes.
<br />In the abandoned fields, erosion has removed all of the
<br />ori~ina] surface soil, and in many places the underlying
<br />shale and sandstone are exposed. Along drainaoeways the
<br />soil has slipped and gullies have fornted, an~ in many
<br />places the underlying material has been exposed. This soil
<br />Las a Inodern[c rate of water intake and low available water
<br />holding capacity, and it erodes Basil}' and tends to slip
<br />during periods of heavy rains.
<br />Included with this soil in mapping were a few areas of
<br />Baca loam and of Samsil clay, gypsmn. Also included, in
<br />areas generally less than 50 feet in diameter, were barren
<br />knobs of hard sandstone, but these make up only a small
<br />percentage of the area mapped. ._
<br />Most of this Thedalund soil is in grass. Much more grass
<br />grows on the deep loamy alhtvium m the drainngeways
<br />than grows on the side slopes. (Capability twit VIo-2;
<br />Clayey Plains range site; tree planting suitability group 5)
<br />Truckton Series
<br />The Truckton series consists of deep, rolling to hilly
<br />soils that occur on uplands in fire western three-fourths
<br />of the county. These soils developed in sandy material
<br />deposited by wind.
<br />
<br />
|