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y well
Ground water: Deep
Salt or alkali: None
Stoniness: None
Described and sampled by: R.W. Fenwick and R.B. Grossman, November 7, 1988.
Soil Number: S88NE-109-020.
Remarks: The upper part of the soil is assumed to be developed in Wisconsin loess and the lower part in Illinoian loess. Part of the delineation lacked sufficient depth of a moist color value of 3 or less for a Mollisol probably because of postcultural erosion. A site was selected in a lower backslope position within a few tens of meters of alluvial fill where postcultural erosion had been relatively less. The position in the landscape is not typical for the naming soil of the map unit.
Ap1 - 0 to 8 cm; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; slightly hard, friable; many fine and very fine roots; common fine vesicular pores; strongly acid; clear smooth boundary.
Ap2 - 8 to 18 cm; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure; slightly hard, friable; many fine and very fine roots; common fine vesicular pores; strongly acid; abrupt smooth boundary.
FIGURE A-1
Interrow on harvested soybeans, 35 to 40 percent covered by crop residue. Not compacted by traffic during harvest. Yellow object in photo is 5x2 cm in size.
A - 18 to 28 cm; dark grayish brown (10YR 3/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak medium subangular blocky structure; hard, friable; common fine roots; numerous worm casts; common fine tubular pores; moderately acid; clear smooth boundary.
BAt - 28 to 38 cm; dark grayish brown (10YR 3/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure parting to moderate very fine subangular blocky; hard, friable; many fine roots; many fine tubular pores; few dark fillings in root channels; faint clay films on faces of peds; moderately acid; clear smooth boundary.
Bt1 - 38 to 51 cm; dark brown (10YR 3/3) silty clay loam, brown (10YR 5/3) dry; weak medium subangular blocky structure parting to moderate fine subangular blocky; hard, friable; common fine roots; few fine tubular pores; faint dark clay films on faces of peds; slightly acid; gradual smooth boundary.
Bt2 - 51 to 76 cm; brown (10YR 4/3) silty clay loam, brown (10YR 5/3) dry; weak medium prismatic structure parting to moderate fine subangular blocky; hard, firm; common fine roots; faint clay films on faces of peds; slightly acid; gradual smooth boundary.
BC1 - 76 to 94 cm; brown (10YR 4/3) and pale brown (10YR 6/3) silty clay loam, brown (10YR 5/3) and very pale brown (10YR 7/3) dry; few fine faint yellowish brown (10YR 5/6) iron concretions; moderate fine prismatic structure; hard, firm; few dark brown (10YR 3/3) coatings on faces of peds; few fine roots; slightly acid; gradual smooth boundary.
BC2 - 94 to 112 cm; brown (10YR 4/3) silty clay loam, brown (10YR 5/3) dry; few fine faint yellowish brown (10YR 5/4 and 5/6) iron concretions; weak medium prismatic structure; hard, firm; streaks of pale brown (10YR 6/3) and very dark grayish brown (10YR 3/2) along surfaces of peds; neutral; gradual smooth boundary.
BCb - 112 to 142 cm; brown (7.5YR 5/4) silty clay loam, light brown (7.5YR 6/4) dry; common fine faint yellowish brown (10YR 5/6 iron concretions; moderate medium prismatic structure; hard, friable; common coatings of dark brown (7.5YR 3/2) on surfaces of peds; neutral; gradual smooth boundary.
C - 142 to 178 cm; brown (7.5YR 4/4) and dark reddish brown (5YR 3/3) silty clay loam, light brown (7.5YR 6/4) and reddish brown (5YR 4/3 dry; few fine faint strong brown (7.5YR 5/6) iron concretions; massive; hard friable, neutral.
FIGURE A-2
Raindrop impact crust specimens from interrow which was compacted during harvest. Object in photo is 1 cm in length.
Surface, near surface: The sampling trench extended across four interrows. Figure A-1 shows an interrow that did not undergo traffic and related compaction during harvest. The adjacent interrow to the right underwent traffic during harvest and related compaction. The other two interrows did not undergo traffic in harvest. Two of the interrows, including the one shown in figure A-1, are 35 to 40 percent covered by crop residue. The other two are 75 to 100 percent covered by crop residue. Linear roughness was measured based on 31 points, 5 cm apart. The standard deviation for the axis of the nontraffic interrow shown in figure 1 was 0.26 cm. For the adjacent interrow that underwent traffic during harvest, the standard deviation was 1.3 cm. Raindrop impact crust was present in convex locations.
Figure A-2 shows the crust specimen. Median rupture resistance of the crust was 5 N with a range of 5 to 7 N for eleven specimens. The crust was in the moderate class. The strongly reconstituted part of the crust was 1 to 2 mm thick. The crust in the concave interrow axis was somewhat weaker. The median was 4 N with a range of 2 to 5 N (weak to moderate) for 11 specimens. Thickness was 2 to 3 mm.
The Ap horizon consists of two subhorizons (fig. A-3). The Ap1 had been subject recently to mechanical bulking and the Ap2 to mechanical compaction. The Ap2 averages 15 cm thick in the second interrow, which was subject to mechanical compaction during harvest. The other three interrows range narrowly in average thickness from 7 to 8 cm. Penetration resistance was measured at 17 points 5 to 10 cm apart where the Ap2 horizon was relatively strongly expressed. The median was 2.2 MPa with a range of 1.7 to 2.6 MPa. The water content was 22.1 percent. The suction should be between 1/3 and 2 bar (Baumer, 1986).
FIGURE A-3
Two subhorizons of the Ap horizon of Sharpsburg silty clay loam. The Ap1 (0-8 cm) has been mechanically bulked and the Ap2 (8-16 cm) has been mechanically compacted
Bakeoven - Condon
Two pedons were sampled for laboratory characterization in the vicinity of the typifying sites of the map unit for the soil survey area. The pedons occur on a convex ridge about 150 m wide that trends northeast to southwest. The area has moderately deep soils on mounds (Condon) and soils that are shallow to bedrock between the mounds (Bakeoven). Mounds occupy about 30 percent of the area shown in figure A-4. Figure A-5, an area of 0.36 ha within which the pedons were sampled, is a photograph that shows the pattern of mounds. The mounds are 15 to 20 m in diameter and 1 to 2 m high. In all probability, the origin is related to periglacial processes combined with movement by wind of finer materials (Green, 1982). The area generally slopes to the west, except for the southeast corner which slopes to the east, and is 40 m from the break to very steep side slopes of the Deschutes River Canyon. Figure A-6 shows the pedon of Bakeoven.
Bakeoven Pedon Description
Location: Wasco County, Oregon, 550 m south and 315 m east of the northwest corner of sec. 15; NE 1/4, SW 1/4, sec. 15, T3S. R14E. Latitude 45° 18' 59" N. Longitude 121° 03' 57" W.
Classification: loamy-skeletal, mixed, superactive, mesic Lithic Haploxerolls
Vegetation: Range
Sandberg bluegrass (Poa secunda J. Presl.) - 45 percent
Stiff sagebrush (Artemisia rigida (Nutt.) Gray) - 20 percent
Phlox (Phlox L.) - 5 percent
Buckwheat (Eriogonum Michx.) - 5 percent
Blue-eyed Mary (Collinsia parviflora Lindlo)
Parent material: Mixed water and wind-transported soil material from the underlying basalt
Physiography: Intermound, part of ridgetop plateau
Relief: 0.5 to 1.5 meters
Elevation: 1,000 meters
Slope: 4 percent
Aspect: 220° (SW)
Erosion: Moderate
Drainage: Well-drained
Ground Water: Very deep
Salt or alkali: None
Stoniness: 2 percent
Described and sampled by: R. Fenwick, R. W. Langridge, and R.B. Grossman, April 4, 1989.
Soil number: S89OR-065-001.
Remarks: Soil Thickness is approximately 5 to 10 cm greater under the sagebrush canopy than outside the canopy.
FIGURE A-4
Sketch map of the area where the Condon and Bakeoven pedons were described and sampled. Cells are 10m on edge.
FIGURE A-5
Landscape of the Bakeoven-Condon complex mapping unit showing pattern of mounds (Condon) and intermounds (Bakeoven).
FIGURE A-6
Profile of Bakeoven very cobbly sandy loam.
A - 0 to 5 cm; dark brown (7.5YR 3/3) very cobbly sandy loam, brown (7.5YR 4/4) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 35 percent pebbles, 20 percent cobbles, and 5 percent stones; neutral; clear smooth boundary.
AB - 5 to 13 cm; dark reddish brown (5YR 3/3) very cobbly sandy loam, dark reddish brown (5YR 3/4) dry; weak fine subangular blocky structure, breaking to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine and few medium roots; many very fine irregular pores; 20 percent pebbles, 35 percent cobbles, and 3 percent stones; neutral; clear smooth boundary.
Bw - 13 to 20 cm; dark reddish brown (5YR 3/3) extremely cobbly sandy loam, dark reddish brown (5YR 3/4) dry; weak fine subangular blocky structure; hard, friable, sticky and plastic; common fine and very fine and few medium roots concentrated along faces of rock fragments; common very fine tubular pores; 20 percent pebbles, 50 percent cobbles, and 2 percent stones; neutral; abrupt wavy boundary.
2R - 20 cm; basalt.
Surface, near surface: The ground surface consists of 10-20 percent sagebrush and 80-90 percent intershrub. Figure A-7 shows the intershrub. Small mounds of soil material, low in rock fragments, are associated with the sage brush. Soil thickness is approximately 5 to 10 cm greater under the sagebrush canopy than outside the canopy. Bare areas 20 to 40 cm across occur. Most are recessed 5 to 10 cm below the vegetated parts. A minority of the bare areas are higher than the surrounding vegetated area and may be recently affected by frost action. The following is a numerical description of the cover for the shrub and intershrub components separately based on point counts.
FIGURE A-7
Close-up photo of ground surface near sample pit for Bakeoven very cobbly sandy loam component of Bakeoven-Condon complex. Yellow marker object is 5x5x2 cm in size.
Component KindMulchCanopyaRock FragmentsAreaArea pct>2mm pctTotal pctEffectiveness pctHeight m>250mm pct75-250mm pct5-75mm pct2-5mm pctShrub1702070
