LOCATION PRESTO ID
Established Series
Rev. RAS/JOH/BAG
03/2023
PRESTO SERIES
The Presto series consists of very deep, somewhat excessively drained soils formed in alluvium. These soils are on stream terraces. Slopes are 0 to 4 percent. Mean annual precipitation is about 250 mm, and the mean annual temperature is about 8 degrees C.
TAXONOMIC CLASS: Sandy over loamy, mixed, superactive, mesic Xeric Haplocalcids
TYPICAL PEDON: Presto loamy sand, in rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 8 cm; grayish brown (10YR 5/2) loamy sand, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine interstitial pores; very slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary.
A2--8 to 20 cm; grayish brown (10YR 5/2) loamy sand, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine tubular pores; very slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.
Bk1 --20 to 43 cm; brown (10YR 5/3) loamy sand, dark grayish brown (10YR 4/2) moist; single grain; soft, very friable, nonsticky, nonplastic; common very fine and fine roots; common very fine and fine tubular pores; slightly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary.
Bk2--43 to 71 cm; light brownish gray (10YR 6/2) loamy sand, dark grayish brown (10YR 4/2) moist; single grain; soft, very friable, nonsticky and nonplastic; common very fine roots; many very fine and fine tubular pores; slightly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary.
2Bk3--71 to 86 cm; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine tubular pores; 20 percent threadlike calcium carbonate masses and 2 percent irregular calcium carbonate masses; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary.
2Bk4--86 to 127 cm; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; weak thick platy structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine and fine tubular pores; 25 percent threadlike calcium carbonate masses and irregular masses; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary.
2Bk5--127 to 150 cm; light brownish gray (10YR 6/2) silt loam, grayish brown (10YR 5/2) moist; weak very coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine tubular pores; 10 percent threadlike calcium carbonate masses and 2 percent irregular calcium carbonate masses; violently effervescent; moderately alkaline (pH 8.4)
TYPE LOCATION: Bingham County, Idaho; USGS topographic quadrangle Firth; latitude 43.253394 degrees north, longitude 112.200571 degrees west, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--9 to 10 degrees C
Depth to calcic horizon--42 to 90 cm
Depth to lithologic discontinuity--42 to 90 cm
Particle-size control section (weighted averages)
Clay content-- 1 to 6 percent in the upper part and 12 to 18 percent in the lower part
Rock fragments--0 to 15 percent gravel
A horizons
Value--4 to 6 dry, 2 to 4 moist
Chroma--2 or 3 dry or moist
Rock fragments--0 to 15 percent gravel
Reaction--pH 7.8 to 8.4
Thickness--12 to 30 cm
Bk horizons
Hue--10YR or 2.5Y
Value--4 or 6 dry; 3 or 4 moist
Chroma--2 or 3 dry or moist
Texture (less than 2 mm fraction)--loamy sand, sand
Rock fragments--0 to 15 percent gravel
Calcium carbonate equivalent-- 3 to 5 percent
Reaction--pH 7.8 to 8.5
Thickness--30 to 60 cm
2Bk horizons
Hue--10YR or 2.5Y
Value--6 or 7 dry; 4 to 6 moist
Chroma--2 to 4 dry or moist
Texture (less than 2 mm fraction)--loam, silt loam
Calcium carbonate equivalent--5 to 25 percent
Reaction--pH 8.3 to 8.8
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform--stream terraces
Elevation-1,280 to 1,675 meters
Slope--0 to 4 percent
Parent material--alluvium dominantly from quartzite and sedimentary rock
Mean annual precipitation--200 to 300 mm
Mean annual air temperature--7 to 8 degrees C
Frost-free period--100 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; 50 to 150 um/sec in the upper part and 5 to 15 um/sec in the lower part.
USE AND VEGETATION: Presto soils are primarily used for irrigated cropland. The potential native vegetation is streambank wheatgrass, Indian ricegrass, basin wildrye, needle and thread grass, lupine, big sagebrush, small rabbitbrush, and bitterbrush.
DISTRIBUTION AND EXTENT: Southeast Idaho. The series is not extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bingham County, Idaho
REMARKS: Diagnostic horizons and other features:
Ochric epipedon--0 to 20 cm (A horizons)
Calcic horizon--71 to 150 cm (2Bk3, 2Bk4, and 2Bk5 horizons)
Particle-size control section--25 to 100 cm
Presto soils have a mesic temperature regime and an aridic moisture regime bordering on xeric.
Previously classified as a Calcisol. Temperature regime changed from frigid to mesic .
National Cooperative Soil Survey
U.S.A.