LOCATION MARIOSA MOEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Chromic Vertic Albaqualfs
TYPICAL PEDON: Mariosa silt loam - on a south-facing slope of 1 percent in a pasture, at 1,080 feet elevation. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak fine granular structure; friable; many very fine and fine roots and few medium roots throughout; common very fine and fine pores with moderate continuity; neutral; abrupt smooth boundary. (4 to 8 inches thick)
E--7 to 11 inches; grayish brown (10YR 5/2) silt loam; weak very fine subangular blocky structure; friable; common fine roots and many very fine roots throughout; common very fine and fine pores with moderate continuity; common fine prominent yellowish brown (10YR 5/6) irregular masses of iron accumulation and common fine faint brown (10YR 5/3) irregular masses of iron accumulations throughout; neutral; abrupt wavy boundary. (0 to 6 inches thick)
Btg1--11 to 20 inches; grayish brown (10YR 5/2) silty clay; moderate fine subangular blocky structure; very firm; common very fine and fine roots throughout; few very fine pores with low continuity; common distinct continuous clay films on faces of peds; common medium prominent reddish brown (2.5YR 4/4) irregular masses of iron accumulations throughout; very strongly acid; clear wavy boundary.
Btg2--20 to 28 inches; grayish brown (10YR 5/2) silty clay; moderate fine subangular blocky structure; very firm; common very fine roots and few fine roots throughout; few very fine pores with low continuity; common distinct continuous clay films on faces of peds; many medium prominent strong brown (7.5YR 4/6) irregular masses of iron accumulation throughout; very strongly acid; clear smooth boundary.
Btg3--28 to 38 inches; grayish brown (10YR 5/2) silty clay loam; moderate medium subangular blocky structure; firm; common very fine roots throughout; few very fine pores with low continuity; few distinct discontinuous clay films on faces of peds; common medium prominent strong brown (7.5YR 4/6) irregular masses of iron accumulation throughout; strongly acid; clear smooth boundary. (the combined thickness of the Btg horizon is 25 to 30 inches)
2Btgx1--38 to 50 inches; light brownish gray (10YR 6/2) silt loam; moderate medium prismatic structure parting to moderate fine subangular blocky structure; very firm; common very fine roots between peds; many very fine pores with low continuity; few faint discontinuous clay films on faces of peds; 60 percent moderate brittleness; few chert pebbles; common medium prominent yellowish brown (10YR 5/6) irregular masses of iron accumulation throughout; moderately acid; gradual smooth boundary.
2Btgx2--50 to 63 inches; light brownish gray (10YR 6/2) silt loam; weak medium prismatic structure parting to weak fine subangular blocky structure; very firm; few very fine roots between peds; many very fine pores with moderate continuity; few faint discontinuous clay films on faces of peds; 60 percent moderate brittleness; 5 percent subrounded chert gravel; many medium prominent yellowish brown (10YR 5/6) irregular masses of iron accumulation throughout; slightly acid; gradual smooth boundary.
2Btgx3--63 to 80 inches; grayish brown (10YR 5/2) silt loam; weak medium prismatic structure; very firm; few very fine roots between peds; many very fine pores with low continuity; few faint discontinuous clay films on faces of peds; 55 percent moderate brittleness; 5 percent subrounded chert gravel; common medium prominent yellowish brown (10YR 5/6) irregular masses of iron accumulation throughout; slightly acid. (The combined thickness of the 2Btgx horizon is 35 inches or more)
TYPE LOCATION: Maries County, Missouri; about 1.5 miles northwest of High Gate; 2400'S., 1500'E. of the NW corner of Sec. 27, T. 40 N., R. 7 W.. White Gate USGS quadrange, 91 degrees, 41 minutes, 41 seconds west Longitude, 38 degrees, 10 minutes, 38 seconds north Latitude.
RANGE IN CHARACTERISTICS: The depth to the top of the Btx horizon is 20 to 40 inches.
The A or Ap horizon has color value of 4 or 5 moist, and 6 or 7 dry. It is very strongly acid to neutral, and may be higher where limed.
The E horizon has color value of 5 or 6. It is very strongly acid to neutral. This horizon may be absent in eroded pedons.
The Btg horizon has hue of 7.5YR to 2.5Y, chroma of 1 or 2, with value of 5 or 6 in the upper part, and as low as 3 in the lower part. Textures are silty clay, clay, or silty clay loam. Reaction is very strongly acid to moderately acid.
The 2Btgx horizon has value of 5 or 6 and chroma of 1 or 2. It is silt loam or silty clay loam. Brittleness ranges from 30 to 60 percent of the matrix. Reaction is very strongly acid to slightly acid.
The 2Btx horizon, where present, has hue of 10YR, value of 5 or 6, and chroma of 4 to 6. It is silt loam. Reaction is very strongly acid to slightly acid. Content of subrounded chert gravel ranges from 0 to 10 percent in the 2Btgx and 2Btx horizons.
COMPETING SERIES: These are the Beckwith, Floraville, and Okaw series. None of these soils have brittleness in the lower part of the solum (Btgx horizon).
GEOGRAPHIC SETTING: Mariosa soils are on level to gently sloping summits or sideslopes of remnant plateaus. Slope gradients typically are less than 2 percent on summit areas, and range up to 3 percent on long sideslopes which are usually eroded. These soils formed in loess overlying an erosional lag concentrate from Pennsylvanian material. Mean annual temperature ranges from 53 to 57 degrees F., and mean annual precipitation ranges from 39 to 44 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the somewhat poorly drained Plato and the moderately well drained Union soils. Both of these soils have a fragipan, and are at lower, more sloping, positions on the landscape.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff potential is high. Permeability is very slow.
USE AND VEGETATION: Most areas are used for pasture. Some areas are used for cultivated crops such as corn, soybeans, and small grain. Native vegetation was hardwood forest.
DISTRIBUTION AND EXTENT: South-central Missouri (MLRA 116B). Mariosa soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Maries County, Missouri, 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of approximately 11 inches (Ap and E horizons); albic horizon - the zone from approximately 7 to 11 inches (E horizon); abrupt textural change - the transition from the E horizon to the Btg1 horizon); argillic horizon - the zone from approximately 11 to 80 inches (Btg horizons and 2Btgx horizons); aquic moisture regime.
Missouri Soil Characterization Lab sample number 94MO125040