LOCATION KNIFEHILL NMEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Pachic Argiustolls
TYPICAL PEDON: Knifehill loam--in rangeland on a convex east facing valley side of 5 percent at an elevation of 7,190 feet. (Colors are for dry soils unless otherwise noted.)
A--0 to 2 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure; soft, very friable, slightly sticky and nonplastic; common fine and many very fine roots; many medium vesicular pores; slightly alkaline (pH 7.6) abrupt smooth boundary. (2 to 6 inches thick)
Bw--2 to 6 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common fine and many very fine roots; common fine irregular pores; neutral (pH 7.2); clear smooth boundary. (0 to 4 inches thick)
Bt1--6 to 11 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; strong medium subangular blocky structure; slightly hard, friable, sticky and plastic; few medium and common fine and very fine roots; common fine irregular pores; common distinct clay films on faces of peds and lining pores; neutral (pH 7.2); clear smooth boundary. (The combined thickness of the Bt horizons is 7 to 34 inches.)
Bt2--11 to 26 inches; very dark grayish brown (10YR 3/2) clay, very dark grayish brown (10YR 3/2) moist; strong medium prismatic structure; hard, firm, very sticky and very plastic; common fine and very fine roots; few fine tubular pores; many prominent clay films on faces of peds and lining pores; neutral (pH 7.2); abrupt smooth boundary. (The combined thickness of the Bt horizons is 7 to 34 inches.)
Btk--26 to 35 inches; brown (10YR 5/3) clay, dark brown (10YR 3/3) moist; weak medium angular blocky structure; hard, firm, very sticky and very plastic; few medium and very fine roots; few very fine irregular pores; few faint clay films on faces of peds; strongly effervescent; calcium carbonate occurs as few very fine irregular soft filaments and masses (1 percent calcium carbonate equivalent); slightly alkaline (pH7.4); clear smooth boundary. (0 to 9 inches thick)
Bk--35 to 65 inches; yellowish brown (10YR 5/4) clay, dark grayish brown (10YR 4/2) moist; massive; hard, firm, very sticky and very plastic; few very fine roots; few very fine irregular pores; strongly effervescent; calcium carbonate occurs as few very fine irregular soft filaments and masses (4 percent calcium carbonate equivalent); slightly alkaline (pH 7.8). (0 to 47 inches thick)
TYPE LOCATION: McKinley County, New Mexico; Pescado Quadrangle; about 1.7 miles northwest of Jacks Lake on the Zuni Indian Reservation; 108 degrees 37 minutes 6 seconds west longitude, 35 degrees 1 minutes 4 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: The SMCS is usually moist, in all parts, for less than 90 cumulative days from April through October. It is usually dry, in some part, for more than 120 cumulative days during the same period. It is continuously moist in some part November through April, but not moist in all parts for 45 consecutive days from January through April. The period of maximum precipitation is July through October. The soil is driest during May and June. Aridic ustic moisture regime.
Soil Temperature: 48 to 53 degrees F
Mollic epipedon: 20 to 40 inches thick
Particle-size control section: 35 to 50 percent clay
Depth to calcium carbonate: 20 to 45 inches
A horizon
Hue: 10YR or 7.5YR
Value: 4 or 5 dry
Chroma: 2 or 3
Reaction: Neutral or slightly alkaline
Bt horizon
Hue: 10YR or 7.5YR
Value: 3 to 5 dry
Chroma: 2 or 3
Texture: clay loam or clay
Reaction: Neutral or mildly alkaline
Bk horizon
Value: 3 or 4 moist
Chroma: 2 to 4 moist
Texture: clay loam or clay
Calcium carbonate equivalent: less than 15 percent
COMPETING SERIES: These are the Conchovar (NM), Irwin (KS), Lubbock (KS), Millpaw (NM), and Nutreeah (NM), Ruidoso (NM), and Tully (KS) series. Conchovar soils have a water table within 40 inches. Ruidoso soils have mean annual temperatures greater than 54 degrees F. Nutreeah soils have hue of 5YR. Millpaw soils have 18 to 35 percent clay in the lower part of the series control section (Bk). Irwin, Lubbock, and Tully soils are in LRR-G and are more moist during May and June.
GEOGRAPHIC SETTING: The Knifehill soils formed in alluvium and stream alluvium derived from sandstone and shale and are on stream terraces on valley floors and fan remnants on valley sides. Slopes are 1 to 5 percent. Elevations range from 6900 to 7500 feet. The mean annual temperature is 46 to 51 degrees F., and the mean annual precipitation is 13 to 16 inches. The frost free period is 100 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Concho and Hosta soils on stream and fan terraces; the Bryway and Galzuni soils on summits of mesas and dipslopes of cuestas; the Toldohn and Vessilla soils on escarpments of mesas and cuestas; and the Valnor and Techado soils on hillslopes of hills and ridges. Concho soils have mollic epipedons less than 20 inches deep. Hosta and Galzuni soils lack a mollic epipedon. Bryway, Toldohn, Vessilla, Valnor and Techado soils are moderately deep and shallow.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, and slow permeability.
USE AND VEGETATION: This series is used for rangeland. Present vegetation is big sagebrush, rubber rabbitbrush, pingue, broom snakeweed, mullein, yarrow, western wheatgrass, blue grama, Indian ricegrass, bottlebrush squirreltail, and mat muhly.
DISTRIBUTION AND EXTENT: West central New Mexico. MLRA 35, LRR-D. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: McKinley County Area, New Mexico; McKinley County and Parts of Cibola and San Juan Counties, 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 26 inches. (A, Bw, Bt1, and Bt2 horizons.)
Pachic feature: The mollic epipedon is greater than 20 inches deep.
Argillic horizon: The zone from 6 to 35 inches. (Bt1, Bt2, and Btk horizons.)
Classified according to Soil Taxonomy Second Edition, 1999.