LOCATION MADERA CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Abruptic Durixeralfs
TYPICAL PEDON: Madera loam - on a slope of less than 1 percent in a field of corn at an elevation of about 210 feet. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 9 inches; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; massive; very hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial and tubular pores; low in organic matter; moderately acid (pH 5.8); clear smooth boundary. (8 to 12 inches thick)
Bt1--9 to 18 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure; extremely hard, firm, slightly sticky and plastic; few very fine roots; few very fine interstitial and tubular pores; few thin clay films on ped faces, common thin clay films as bridges between sand grains; neutral (pH 6.9); abrupt smooth boundary. (8 to 15 inches thick)
2Bt2--18 to 25 inches; yellowish brown (10YR 5/4) sandy clay, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; extremely hard, very firm, very sticky and plastic; few very fine roots; few very fine tubular and many very fine interstitial pores; continuous moderately thick clay films on ped faces and lining pores and as bridges between sand grains; neutral (pH 7.1); abrupt smooth boundary. (3 to 15 inches thick)
Bqkm--25 to 28 inches; yellowish brown (10YR 5/4) indurated iron- silica cemented duripan; dark yellowish brown (10YR 4/4) moist; lime segregated in fine seams; cementation strongest in upper few inches becoming less with increasing depth; dark colored manganese stainings occur throughout the duripan, presumably along old structural planes; gradual smooth boundary. (4 to 18 inches thick)
3C--28 to 60 inches; pale brown (10YR 6/3) sandy loam, dark brown and brown (10YR 4/3, 5/3) moist; massive; hard, firm, nonsticky and nonplastic; many very fine interstitial pores; slightly stratified and weakly cemented in places; mildly alkaline (pH 7.5).
TYPE LOCATION: Madera County, California; about 5 miles south of Chowchilla and about 12 miles northwest of Madera, 600 feet north, 100 feet east of W1/4 corner, sec. 20, T. 10 S., R. 16 E., Chowchilla Quadrangle.
RANGE IN CHARACTERISTICS: Depth to the duripan ranges from 20 to 40 inches. The mean annual soil temperature ranges from 60 degrees to 65 degrees F and the soil temperature is not below 47 degrees F at any time. The soil, at depths of about 7 to 24 inches or immediately above the duripan, is dry in all parts from June to November and is moist in some or all parts the rest of the year.
The A horizon is 10YR 6/4, 6/3, 6/2, 5/4, 5/3, 5/2; or 7.5YR 5/2. Moist colors are 10YR 4/4, 4/3, 4/2, 3/4, 3/3 or 7.5YR 4/2. Moist value or chroma is 4 in some part. It is sandy loam, fine sandy loam or loam. Reaction is moderately acid to neutral. Has distinct or prominent mottles in some pedons that have been basin irrigated for rice production.
The Bt horizon is 10YR 5/4, 5/3 6/3; 7.5YR 6/4, 5/4, 5/2 4/4; or 5YR 6/3. Moist colors are 10YR 5/4, 4/4, 4/3 or 3/3; or 7.5YR 5/4, 4/4, 4/2; 5YR 4/4, 4/3, or 3/4. Reaction is slightly acid or neutral. Clay content ranges from 20 to 30 percent.
2Bt horizon is 10YR 5/4, 5/3 6/3; 7.5YR 6/4, 5/4, 5/2 4/4; or 5YR 6/3. Moist colors are 10YR 5/4, 4/4, 4/3 or 3/3; or 7.5YR 5/4, 4/4, 4/2; 5YR 4/4, 4/3, or 3/4. It is clay, sandy clay, or clay loam. Reaction is neutral to moderately alkaline. Clay content ranges from 35 to 55 percent. It has abrupt upper boundary with at least 15 percent clay increase.
The duripan has colors similar to those in the Bt horizon and is strongly cemented to indurated with silica, iron and lime. Silica is the predominant cementing agent with lime segregated in seams. The duripan grades with depth into less strongly cemented substrata.
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING: Madera soils are on hummocky, gently sloping to undulating terraces at elevations of 10 to 250 feet. Meandering drainageways and closed depressions fill with water to form vernal pools in the winter months. Slopes range from 0 to 9 percent. The soils formed in alluvium mainly from granitic rock sources but may be mixed. The climate is subhumid with dry hot summers and cool moist winters. Mean annual precipitation varies from 9 to 18 inches. Mean January temperature is 45 degrees F; mean July temperature is 80 degrees F; mean annual temperature is 60 to 63 F. Frost-free period is over 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alamo, Cometa, Whitney, Exeter and Rocklin soils. Alamo soils are clayey throughout. Cometa and Whitney soils lack a duripan. Exeter and Rocklin soils lack an abrupt boundary with an absolute increase of at least 15 percent clay within the argillic horizon.
DRAINAGE AND PERMEABILITY: Well or moderately well drained; medium to very slow runoff; very slow permeability.
USE AND VEGETATION: Used mainly for irrigated cropland such as alfalfa, almonds, grapes, oranges, rice and tomatoes. They are also used as irrigated pasture, dry farmed grain and annual range. Vegetation is annual grasses and forbs.
DISTRIBUTION AND EXTENT: Eastern side of the Sacramento and San Joaquin Valleys. The soils are extensive in MLRA-17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Madera County, California, 1910.
REMARKS: The Madera series was formerly classified as fine, montmorillonitic, thermic Typic Durixeralfs but was reclassified because it has an abrupt boundary with an absolute increase of at least 15 percent clay at the upper boundary or within the argillic horizon. In addition, the range of characteristics was narrowed to avoid overlapping the similar San Joaquin series.
Diagnostic horizons and features recognized in this pedon are:
Argillic horizon - the zone from 9 to 25 inches (Bt1, 2Bt2)
Indurated iron-silica cemented duripan- the zone from 25 to 28 inches (Bqkm)