LOCATION ILDEFONSO               NM

Established Series
Rev. RJA/LWH/WJG
09/2018

ILDEFONSO SERIES

The Ildefonso series consists of very deep, well drained, moderately rapidly permeable soils that formed in alluvium, colluvium and eolian sediments derived from quartzite, monzonite, granite, basalt, gneiss, schist and limestone. Ildefonso soils are on mesas, fan terraces, eroded fan remnants, escarpments, and hills. Slopes are 0 to 75 percent. The mean annual precipitation is 11 inches and the mean annual temperature is 50 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ustic Haplocalcids

TYPICAL PEDON: Ildefonso fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 3 inches; light yellowish brown (10YR 6/4) fine sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; 10 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 6 inches thick)

Bw--3 to 9 inches; brown (7.5YR 5/3) fine sandy loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; 10 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (6 to 10 inches thick)

Bk1--9 to 13 inches; light brown (7.5YR 6/4) gravelly fine sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; many fine roots; 20 percent gravel; strongly effervescent with visible calcium carbonate occurring as concretions, as thin seams and streaks, and as coatings on gravel; moderately alkaline (pH 8.4); clear smooth boundary. (4 to 20 inches thick)

Bk2--13 to 70 inches; pink (7.5YR 7/3) very gravelly fine sandy loam, light brown (7.5YR 6/3) moist; massive; hard, friable, nonsticky and slightly plastic; common fine and medium roots; weakly cemented in some parts; 40 percent gravel and cobbles; violently effervescent with visible calcium carbonate occurring in finely divided forms, as concretions and as coatings; moderately alkaline (pH 8.4).

TYPE LOCATION: Torrance County, New Mexico; about 5 miles SW of Estancia; NE1/4NE1/4 Sec. 33, T.6N., R.8E.; 106 degrees, 05 minutes, 54 seconds west longitude; 34 degrees, 42 minutes, 32 seconds north latitude

RANGE IN CHARACTERISTICS:

Soil Temperature: 47 to 59 degrees F.

Soil Moisture: SMCS is moist in some part at least 25 percent of the time the soil temperature exceeds 41 degrees F. The driest month is November.

Rock fragments: Average 35 to 75 percent in the particle-size control section cobbles and/or stones may comprise up to 40 percent of the total. Surface layer contains from 10 to 55 percent coarse fragment.

A and Bw horizons
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 6, dry or moist
Texture: fine sandy loam, sandy loam, very fine sandy loam, loam

Bk horizon
Hue: 5YR, 7.5YR, 10YR
Value: 5 to 8 dry, 4 to 7 moist
Chroma: 1 to 4, dry or moist
Calcium carbonate equivalent: 15 to 40 percent; in some pedons this horizon is weakly cemented.
Texture: sandy loam, loam

COMPETING SERIES: These are the Buffcreek(WY), Clapper(UT), Claprych (WY), Placitas(NM), Raydawn (NM), Seis(NM), and Strych(UT) soils. Buffcreek and Clapper soils have more than 18 percent clay in the particle-size control section. Claprych soils have hue of 10YR throughout the solum. Placitas, and Seis soils are 20 to 40 inches deep to lithic or paralithic contacts. Raydawn soils have a lithologic discontinuity withing 80 inches. Strych soils are dry for longer periods of time (April through June).

GEOGRAPHIC SETTING: These soils formed mostly on mesas, eroded fan remnants, escarpments, fan terraces, and hills. The soils formed from alluvium, colluvium and eolian materials derived from quartzite, monzonite, granite, basalt, gneiss, schist and limestone. Elevation ranges from 5,000 to 7,000 feet. Slope ranges from 0 to 75 percent. The average mean annual temperature is 48 to 55 degrees F. The mean annual precipitation is 9 to 13 inches. Frost-free period is 120 to 175 days. Some area outside of New Mexico have been correlated with elevations as low as 4500 feet, precipitation as high as 15 inches, temperatures as low as 42 degrees, and frost free period as long as 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Harvey, Scholle, Tesajo, Willard, and Witt soils. Harvey and Scholle soils have 18 to 35 percent clay in the control section and Scholle soils have an argillic horizon. Tesajo soils have a thick mollic epipedon. Willard soils have more than 40 percent carbonates in the control section. Witt soils have less than 15 percent fine sand or coarser.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately rapid. Runoff is negligible on slopes less than 1 percent, very low on 1 to 5 percent slopes, low on 5 to 20 percent slopes, and medium on slopes greater than 20 percent.

USE AND VEGETATION: These soils are used as rangeland. The vegetation is dominantly blue grama and muhly together with black grama, hairy grama, sideoats grama, juniper, and sacahuista.

DISTRIBUTION AND EXTENT: Northcentral New Mexico and western Colorado. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Lower Colorado Area, Colorado, 1970

REMARKS: The distinction between Ildefonso and Strych is not well defined.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 3 inches (A horizon)
Calcic horizon - 13 to 70 inches (Bk horizons)

Classified according to Keys to Soil Taxonomy Twelfth Edition, 2014.

Update and revisions for the correlation of Kane County, UT642, July 2017, CEM

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National Cooperative Soil Survey
U.S.A.