LOCATION CALVERT MDInactive Series
TAXONOMIC CLASS: Fine-silty, mixed, mesic Typic Fragiaqualfs
TYPICAL PEDON: Calvert silt loam - forested. (Colors are for moist soils.)
A1--0 to 3 inches; olive gray (5Y 5/2) silt loam; weak, very thin platy structure; friable, sticky and slightly plastic; roots common; extremely acid; gradual smooth boundary. (1 to 3 inches thick)
A2g--3 to 13 inches; gray (5Y 5/1) silt loam, with common fine and medium prominent mottles of brown or dark brown (10YR 4/3); very weak, thin platy structure; friable, sticky and plastic; few roots; extremely acid; abrupt smooth boundary. (6 to 10 inches thick)
B2tg--13 to 25 inches; gray (5Y 5/1) silty clay loam, with common medium prominent mottles of yellowish-red (5YR 4/6; strong, fine and medium blocky structure; hard, firm, sticky and plastic; few or no roots; thin, indistinct clay coatings; very strongly acid; clear, smooth to wavy boundary. (9 to 12 inches thick.)
Bx--25 to 36 inches; gray or light gray (5Y 6/1) silty clay loam, with abundant medium prominent mottles of strong brown (7.5YR 5/6) and yellowish-brown (10YR 5/8); coarse prismatic and weak, thin and medium platy structure; extremely hard, very firm and somewhat brittle, sticky and plastic; no roots; distinct olive (5Y 5/6) clay coats; traces of mica flakes; some rock fragments; medium acid; clear smooth boundary. (8 to 11 inches thick.)
IICg--36 to 43 inches; gray (N 5/0) clay, with common medium and coarse distinct mottles of olive and light olive brown (5Y 5/6 and 2.5Y 5/4); structureless, massive; extremely firm, very sticky and very plastic; some mica flakes and rock fragments; medium to slightly acid; abrupt irregular boundary. (4 to 20 inches thick.)
IIR--43 inches; hard greenish serpentine.
TYPE LOCATION: Howard County, Maryland; 500 feet northeast of G&E pole 13, on Kerger Road.
RANGE IN CHARACTERISTICS: Thickness of solum ranges from 24 to 36 inches. Depth to bedrock is 3 to 6 feet. Unlimed acidity decreases with depth, and base saturation in the C horizon is greater than 60 percent. Mean annual temperatures are less than 59 degrees F. Colors in A horizons are in hues 10YR to neutral, with values of 4 to 6 and chromas of 0 to 3. Matrix hues in B horizons are 10YR to 5Y, with values of 4 to 6 and chromas of 1 or sometimes 2. Mottles in B horizons are in hues 5Y to 5YR, with values of 4 or 5 and chromas of 3 to 8. B2 and Bx horizons may be silty clay loam or heavy silt loam. The IIC horizon has a matrix hue centered on neutral, but which ranges to include 5Y, 5G, and 5GY; values, chromas, and mottling are similar to those in B horizons. The IIC is finer in texture than the solum, but some profiles have a thin C horizon between the IIC and the solum which is somewhat coarser than the solum. There are few if any coarse fragments in the solum, but these are sometimes common in IIC horizons.
COMPETING SERIES: These include the Clermont, Croton, Doylestown, Sheffield, Thorndale, Frenchtown, and Loysville soils. The Clermont soils have solums 80 to 120 inches in thickness, and are 7 to 20 feet to bedrock. The Croton soils have subsoil aggregates in which interior hues are 7.5YR to 5YR, inherited from the natural colors of the regolith. The Sheffield soils have thicker solums than the Calvert and have calcareous C horizons. The Doylestown soils have limestone bedrock closely under the fragipan. The Thorndale soils have finer-textured fragipans than the Calvert soils and conforming C horizons that range to clay in texture. Frenchtown and Loysville soils have more than 15 percent sand and coarse fragments in the control section, and are classes as fine-loamy.
GEOGRAPHIC SETTING: The Calvert soils have developed in a thin mantle of silty material, probably local alluvium from areas of basic rocks, over residuum from serpentine or related rocks. They occupy flats and depressions, frequently around the heads of drains. Slopes are usually less than 5 percent. The climate is temperate and humid, with a mean annual temperature of 45 to 55 degrees F. and mean annual precipitation of about 40 inches.
OSED scanned by SSQA. Last revised by state on 12/69.