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Soil Survey Manual - Appendix 3Three appendices are included. The first gives examples of descriptions of soil series. The second describes three map units that are quite different in their systematics. The third appendix contains point information for soils of the three map units.
Pedon DataTable of Contents
Pedons were sampled in each of the map units that are described in Appendix 2. Site data, a detailed soil profile description, and laboratory characterization data are given. Recorded field observations show several of the recently introduced measurements. Most measurements and classifications are discussed in Chapter 3. The observations are not inclusive of what should or could be done. For each pedon, selected laboratory data are given. Sharpsburg Pedon Description
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 acid1 ; 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. 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. 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).
Click links to see Sharpsburg Series Primary
Characterization Data Bakeoven - CondonTwo 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
Remarks: Soil Thickness is approximately 5 to 10 cm greater under the sagebrush canopy than outside the canopy. Click links to see Bakeoven Series Primary
Characterization Data
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.
The soil-loss ratio (Wischmeier and Smith, 1978) of the shrub was 0.04 and the intershrub 0.16. The weighted average overall soil-loss ratio is 0.14. Roughness of the intershrub area was measured based on 31 points 10 cm apart with a correction for slope. The standard deviation was 1.3 cm. The overall color value of the dry ground surface, inclusive of the rock fragments, was 4. Condon Pedon Description
A - 0 to 8 cm; dark brown (7.5 YR 3/2) loam, brown (7.5 YR 4/3) dry; weak fine subangular blocky structure parting to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 5 percent pebbles; neutral; clear smooth boundary. AB - 8 to 18 cm; dark brown (7.5 YR 3/2) loam, brown (7.5 YR 4/3) dry; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine irregular pores; 5 percent pebbles; neutral; clear smooth boundary. Bw1 - 18 to 38 cm; dark brown (7.5 YR 3/3) loam, brown (7.5 YR 4/3) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; 5 percent pebbles; neutral; clear smooth boundary. Bw2 - 38 to 58 cm; dark brown (7.5 YR 3/3) loam, brown (7.5 YR 4/3) dry; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; 5 percent pebbles; neutral; clear wavy boundary. BC - 58 to 66 cm; dark brown (7.5 YR 3/3) loam, brown (7.5 YR 4/3) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; 5 percent pebbles; neutral; abrupt wavy boundary. 2R - 66 cm; fractured basalt. Surface, near surface: The outermost 1 to 3 m of the mounds (about half of the mound area) was subject to more traffic by grazing animals than the central portion. The outer portion has 30 to 40 percent bare soil compared to 10 percent or less in the central portion. The soil-loss ratio (Wischmeier and Smith, 1978) is 0.18 for the periphery and 0.07 for the central part. Click links to see Condon Series Primary Characterization
Data Lithic Haplargids
A - 0 to 4 cm; yellowish red (5YR 4/6) sandy loam, reddish brown (5YR 4/4) moist; weak fine granular structure; soft, friable, nonsticky, nonplastic; few very fine and fine roots; 5 percent fine pebbles; very slightly effervescent; moderately alkaline; abrupt smooth boundary. Bt - 4 to 13 cm; yellowish red (5YR 4/8) sandy clay loam, yellowish red (5YR 4/6) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, slightly sticky, plastic; common faint clay films in pores and clay bridging sand grains; few fine, irregular soft masses of carbonates; few very fine and fine roots; few fine tubular pores; 5 percent fine pebbles; strongly effervescent, strongly alkaline; clear smooth boundary. Btk - 13 to 23 cm; yellowish red (5YR 4/8) clay loam, yellowish red (5 YR 4/6) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky, plastic; common faint clay films on faces of peds and clay bridging sand grains; common fine platelike soft filaments and masses of carbonates; few fine and very fine roots; few fine tubular pores; 5 percent fine pebbles; violently effervescent; moderately alkaline; clear wavy boundary. BCk - 23 to 35 cm; grayish brown (10YR 5/2) and reddish brown (5YR 5/3) gravelly clay loam; massive; hard, firm; common medium and coarse irregular soft masses of carbonates; 20 percent pebbles; very few fine roots; violently effervescent; moderately alkaline; abrupt wavy boundary. 2R1 - 35 to 43 cm; hard olive gray (5Y 5/2) fractured sandstone; fracture surfaces coated with reddish brown (5YR 5/3) coatings; carbonate as few small pendents on underside of fragments. 2R2 - 43 cm; moderately hard, olive gray (5Y 5/2) thinly bedded sandstone. A numerical description follows of the cover for the shrub and intershrub components separately. Areal percentages were obtained by point counting.
Based on the cover information, the soil-loss ratio (Wischmeier and Smith, 1978) was 0.27 for the shrub component and 0.52 for the intershrub. The overall soil-loss ratio was 0.48. The soil-loss ratio may be slightly lower during July and August, the period of maximum water erosion, because of more vegetation. Roughness was determined for 31 points, 5 cm apart in a bare area that was relatively smooth along the assumed direction of overland flow. The standard deviation corrected for slope was 0.34 cm. The dry rupture resistance of the crust was 3N based on the average of nine determinations from each of two places a few meters apart. The thickness of the reconstituted part of the crust was 1 to 2 mm. Click links to see a lithic haplargid Primary
Characterization Data Figure A-8 is a map of the area where the pedon was sampled and figure A-9 shows the landscape. The sample pedon is shown in figure A-10 and a close up of the ground surface near the pedon is shown in figure A-11.
Footnote
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