LOCATION HARMON OK+TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, thermic, shallow Typic Ustorthents
TYPICAL PEDON: Harmon gravelly silt loam--5 percent slope, cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; light reddish brown (5YR 6/3) gravelly silt loam, reddish brown (5YR 5/3) moist; moderate fine and medium granular structure; few very fine and fine roots; common very fine and fine pores; common fine carbonate concretions; 60 percent calcium carbonate equivalent; 30 percent angular dolomite gravel; violently effervescent; moderately alkaline; abrupt smooth boundary. (Thickness ranges from 4 to 9 inches)
ACk--7 to 16 inches; light brown (7.5YR 6/4) very gravelly silt loam, brown (7.5YR 5/4) moist; massive; very few very fine and fine roots; common very fine and fine and few medium pores; common fine carbonate concretions; 80 percent calcium carbonate equivalent; 56 percent angular dolomite gravel; violently effervescent; moderately alkaline; abrupt smooth boundary. (Thickness ranges from 0 to 11 inches)
Cr1--16 to 21 inches; light gray (10YR 7/1) partially weathered, fractured dolomite bedrock; violently effervescent; moderately alkaline; abrupt smooth boundary. (Thickness ranges from 0 to 16 inches)
Cr2--21 to 30 inches; 28 percent pale yellow (5Y 7/4) and 28 percent light greenish gray (5GY 7/1) and 28 percent light red (2.5YR 7/8) and 16 percent brown (10YR 5/3) interbedded claystone and siltstone bedrock; strongly effervescent; moderately alkaline.
TYPE LOCATION: Jackson County, Oklahoma; from the intersection of OK State Highway 34 and U. S. Highway 62 in Duke; about 2.5 miles south on Highway 34; 2.75 miles west on county road; 550 feet north in cultivated field. (1350 feet east and 550 feet north of the southwest corner of Sec. 22, T.2 N., R.23 W.); U.S.G.S. Quad: Prairie Hill; Latitude: 34N, 37, 28; Longitude: 99W, 33, 34.
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock ranges from 6 to 18 inches. The solum averages 35 to 65 percent coarse fragments, consisting mainly of dolomite but also contains claystone, siltstone, and gypsum parafragments in some pedons. Calcium carbonate equivalent in the control section ranges from 40 to more than 80 percent in the less-than-20 mm soil fraction. Reaction is moderately alkaline throughout.
The A horizon has hue of 5YR or 7.5YR, value of 4 to 6, and chroma of 3 or 4. Texture of the fine earth fraction is silt loam or loam. Effervescence ranges from slight to violent and visible carbonates range from few to many.
The ACk horizon, where present, has hue of 5YR to 10YR, value of 5 to 7, and chroma of 3 or 4. Texture of the fine earth fraction is silt loam or loam. Effervescence is typically violent and visible carbonates range from common to many.
The Cr1 horizon, where present, consists of partially weathered, fractured gray dolomitic limestone. Space of fractures ranges from 4 to 10 inches or more.
The Cr2 horizon consists of interbedded claystone and siltstone in shades of gray, brown, and red.
COMPETING SERIES: This is the Eddy series in the same family. Similar soils are the Cottonwood, Doss, Ector, Lueders, Pidcoke, and Talpa series. Eddy soils are in a slightly warmer and wetter climate and formed in Cretaceous age chalk. Cottonwood soils are very shallow over gypsum and contain less than 10 percent coarse fragments. Doss soils have a mollic epipedon. Ector, Lueders, Pidcoke, and Talpa soils have a mollic epipedon and a lithic contact.
GEOGRAPHIC SETTING: Harmon soils are found on summit and shoulder slopes in karst topography of the Blaine Formation of Permian age. These soils formed in dolomite limestone layers that are interbedded with claystone, siltstone, and gypsum. Slope ranges from 1 to 8 percent. Mean annual precipitation ranges from 20 to 26 inches. Mean annual air temperature ranges from 60 to 64 degrees F. Frost free days range from 200 to 230 days. Elevation ranges from 1400 to 2100 feet. The Thornthwaite annual P-E index ranges from 32 to 40.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aspermont, Cottonwood, La Casa, Nipsum, and Talpa series. Aspermont, La Casa, and Nipsum soils are deep or very deep to Permian age redbed sediments and are on lower landscape positions. Cottonwood soils are very shallow to gypsum and are on similar landscape positions. Talpa soils are on similar landscape positions, have a mollic epipedon and a lithic contact. Sinkholes are also a common feature of the karst topography.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate in the solum and very slow to slow in the bedrock. Runoff is high on 0 to 1 percent slopes and very high on 1 to 8 percent slopes.
USE AND VEGETATION: Used mainly for cropland. Many areas are idle and have been seeded to Old World bluestem or other native grasses. Native range vegetation consists mainly of sideoats grama, little bluestem, silver bluestem, buffalograss, slim tridens, threeawn, fall witchgrass, with various prennial forbs. Mesquite and cactus invade these areas if not controlled.
DISTRIBUTION AND EXTENT: The western part of the Central Rolling Red Plains of Oklahoma and Texas LRR H (MLRA 78B). These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Harmon County, Oklahoma; 1940.
REMARKS: The Harmon series was placed on the inactive list in 1963 and is being reestablished in the 2000 Jackson County, Oklahoma update survey. The reactivated series concept is the same as the original series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 7 inches (Ap horizon).
Paralithic contact--at 16 inches.
Range Site: Very Shallow - 078BY091TX.
ADDITIONAL DATA: NSSL data from Jackson County, OK (S97OK-065-009)
TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999.