Table 1. Selected characteristics of the dominant soils in MLRA 116A that relate to water and solute transport.
Great Group/ Series
 Family
Approximate Area
Drainage
Class
Permeability
Class
Slope Range
Hydrologic Group
   
acres
    
 %
  
Hapludalfs            
Arkana Very-fine, mixed, mesic Mollic
311,378
well
very slow
3 - 20
C
Bardley Very-fine, mixed, mesic Typic
265,699
well
moderate
2 - 100
C
Gatewood Very-fine, mixed, mesic Oxyaquic
205,864
moderately well
slow
2 - 35
C
Ocie Loamy-skeletal over clayey, mixed, mesic Oxyaquic 
140,842
moderately well
slow
2 - 35
C
Paleudalfs            
Gepp Very-fine, mixed, mesic Typic
453,129
well
moderate
1 - 40
B
Goss Clayey-skeletal, mixed, mesic Typic
250,301
well
moderate
2 - 70
B
Portia Fine-loamy, siliceous, mesic Typic
172,062
well
moderate
1 - 30
C
Hapludults            
Agnos Clayey, mixed, mesic Typic
150,160
well
very slow
2 - 35
D
Boden Clayey, mixed, mesic Typic
147,557
well
moderately slow
1 - 20
C
Gassville  Clayey, mixed, mesic Typic
146,740
well
very slow
1 - 40
C
Paleudults            
Brockwell  Coarse-loamy, siliceous, mesic Typic 
192,392
well
moderate
3 - 20
B
Noark Clayey-skeletal, mixed, mesic Typic
465,897
well
moderate
1 - 45
B
Clarksville Loamy-skeletal, siliceous, mesic Typic 
1,920,997
somewhat excessive
moderate
1 - 60
B
Coulstone Loamy-skeletal, siliceous, mesic Typic 
127,677
somewhat excessive
moderately rapid
5 - 60
B
Doniphan Clayey, mixed, mesic Typic
476,308
well
moderate
2 - 60
B
Poynor Loamy-skeletal over clayey, siliceous, mesic Typic 
197,758
well
moderate
2 - 60
B
Fragiudalfs            
Lebanon Fine, mixed, mesic Typic
113,650
moderately well
moderately slow/slow
2 - 14
C
Fragiudults            
Captina Fine-silty, siliceous, mesic Typic
459,616
moderately well
slow
1 - 12
C
Nixa Loamy-skeletal, siliceous, mesic Glossic 
629,095
well
very slow
1 - 20
C
Hapludolls            
Moko Loamy-skeletal, mixed, mesic Lithic
332,077
well/somewhat excessive
moderate
3 - 80
D
Udifluvents            
Midco Loamy-skeletal, siliceous, nonacid, mesic Typic 
146,755
somewhat excessive
moderately rapid
1 - 4
A
Rock outcrop   
150,371
        

Table 2. Morphological characteristics of a typical Nixa soil.
Horizon
Depth
Interval (in)
 Description
Ap
0 - 2
 Very dark grayish brown (10YR 3/2) very gravelly silt loam; weak fine granular structure; friable; common fine roots; very fine pores; about 40% by volume chert fragments, 1/4 inches in diameter; strong acid; clear smooth boundary.
E
2-11
 Brown (10YR 5/3) very gravelly silt loam; moderate fine and medium roots; common fine pores; about 40%by volume chert fragments 1/4 to 4 inches in diameter; strongly acid; gradual smooth boundary.
Bw
11- 22
 Light yellowish brown (10YR 6/4) extremely gravelly silt loam; weak to moderate fine subangular blocky structure; friable; common fine and medium roots; few fine pores; about 60% by volume chert fragments 1/4 to 4 inches in diameter; very strongly acid; gradual wavy boundary.
Btx
22-44
 Yellowish brown (10YR 5/4) extremely gravelly silt loam; weak fine subangular blocky structure; firm and brittle; few fine roots mainly in gray; few fine pores; common faint clay films on faces of some peds and on some chert fragments; about 70% by volume chert fragments 1/4 to 6 inches in diameter; common medium distinct strong brown (7.5YR 5/6) and few fine prominent yellowish red (5YR 5/6) masses of iron accumulation in matrix; common medium distinct light brownish gray (10YR 6/2) clay depletions in matrix; few fine Fe/Mn concretions; few medium black masses of Mn accumulation on faces of some chert fragments; very strongly acid gradual wavy boundary.
Bt
44-80
 Variegated yellowish red (5YR 4/6) strong brown (7.5 YR 5/6) and light brownish gray (10YR 6/2) extremely gravelly silty clay loam; weak medium angular blocky structure to massive; firm; some peds slightly brittle; few fine pores; may faint clay films on faces of peds and chert fragments; about 80% by volume chert fragments up to 6 inches in diameter; very strongly acid
Location: Marion County, Arkansas, 4.1 miles north on Arkansas Highway 14 from junction with US Highway 62, right side of highway, NW1/4SE1/4SW1/4, sec. 21, T. 19 N., R. 16W.
Vegetation: Upland hardwood forest; black oaks, blackjack oaks, post oaks, and hickory.
Parent Material: Residuum from cherty limestone
Physiography: Nearly level to moderately sloping ridgetops. Slopes range from 1 to 20% with dominant range from 3 to 12 %.
Sampled and described by: L. B. Ward
Date: May 15, 1974

Table 3. Morphological characteristics of a representative Captina soil.
Horizon
Depth
Interval (in)
 Description
Ap1 
0 -8
 Dark brown (10YR 4/3) silt loam; weak medium granular structure; friable ; many fine roots; few fine pores; about 5% by volume chert fragments, 1/4 to 2 inches in diameter; medium acid; clear smooth boundary
BA 
8 - 13
 Yellowish brown (10YR 5/4) silt loam; weak, medium subangular blocky structure; friable; common fine roots; many fine and medium pores; about 5% by volume chert fragments 1/4 to 2 inches in diameter; strongly acid; clear smooth boundary.
Bt
13 - 24
 Strong brown (7.5 YR5/6) silty clay loam; moderate medium subangular blocky structure; friable few faint clay films on faces of some peds and lining some pores; common fine roots; many fine and medium tubular pores; about 5% by volume chert fragments 1/4 to 3 inches in diameters; strongly acid; clear wavy.
Btx1
24-32
 Strong brown (7.5 YR 5/6) gravelly silty clay loam; moderate medium angular blocky structure; firm and brittle; many faint clay films on faces of peds and lining pores; few fine roots; many fine vesicular pores; about 15% by volume chert fragments 1/4 to 4 inches in diameter; common medium distinct light brownish gray (10YR 6/2) iron depletions in matrix; few fine Fe/Mn concretions; very strongly acid; gradual smooth boundary.
Btx2
32-44
 Variegated, light gray (10YR 6/1), strong brown (7.5 YR 5/8), yellowish red (5YR 5/6) and yellowish brown (10YR 5/4) extremely gravelly silty clay loam; thick medium platy structure parting to moderate medium angular blocky structure; firm and brittle; many faint clay films on faces of peds, chert fragments and lining pores; few fine roots; many fine vesicular pores; about 70% by volume chert fragments up to 6 inches in diameter; very strongly acid; diffuse irregular boundary.
Bt
44-80
 Red (2.5 YR 4/6) gravelly clay; moderate fine angular blocky structure; firm; many prominent clay films on faces of peds and lining pores; few fine roots; many fine vesicular pores; about 15% by volume chert fragments up to 4 inches in diameter and about 2% angular weathered limestone fragments; common medium prominent gray (10YR 6/1) iron depletions in matrix and common medium distinct strong brown (7.5YR 5/6) masses of iron accumulation in matrix; very strongly acid..
Location: Baxter County, Arkansas, NE1/4NW1/4, sec. 31, T.20N., R. 14W.Parent Materials: Residuum or cherty limestone
Vegetation: Meadow of native grasses and tall fescue
Physiography: nearly level to moderately sloping uplands. Slopes range from 1 to 12%, with dominant range from 1 to 8%.
Sampled and Described by: L. B. Ward and R. T. McCright
Date: September 13, 1973

Table 4. Morphological characteristics of a representative Clarksville soil.
Horizon
Depth
Interval (in)
 Description
Oi
1-0
 Partly decomposed hardwood leaves, twigs and pine needles.
A
0-3
 Dark grayish brown (10YR 4/2) very cherty silt loam; moderate medium granular structure; friable; many roots; 50% chert fragments 1/4 to 5 inches in diameter; strongly acid; clear smooth boundary
E
3-12
 Pale brown (10YR 6/3) very gravelly silt loam; weak fine subangular blocky structure; friable; common medium and coarse roots; common fine pores; about 35% by volume chert fragments 1/4 to 4 inches in diameter; strongly acid; gradual smooth boundary.
BE
12-20
 Strong brown (7.5YR 5/6) extremely gravelly silt loam; weak fine subangular blocky structure; friable; few fine roots; few fine pores; about 70% by volume chert fragments 1/4 to 4 inches in diameter; few medium distinct light yellowish brown (10YR 6/4) iron depletions in matrix; very strongly acid; gradual smooth boundary.
Bt1
20-32
 Yellowish red (5YR 5/6)extremely gravelly silty clay loam; moderate fine subangular blocky structure; friable; some peds slightly brittle; few fine roots; few fine and very fine visicular pores; common faint clay films on faces of some peds and on some chert fragments; about 60% by volume chert fragments 1/4s to 6 inches in diameter; common fine distinct light yellowish brown (10YR 6/4) iron depletions in matrix; few medium black masses of Mn accumulation on faces of some chert fragments; very strongly acid; clear smooth boundary.
Bt2
32-51
 Red (2.5YR 4/6) extremely gravelly silty clay; moderate fine angular blocky structure; firm; many prominent clay films on faces of and on chert fragments; about 75% by volume chert fragments 1/4 to 6 inches in diameter; very strongly acid; gradual smooth boundary.
Bt3
51-80
 Red (2.5 YR 4/6) extremely gravelly silty clay; weak fine angular blocky structure; firm; many prominent clay films on faces of and on chert fragments; about 80% by volume chert fragments 1/4 to 6 inches in diameter; very strongly acid.
Location: Marion County, Arkansas NW 1/4SW1/4NW 1/4, Sec. 34, T 17N., R. 15W.
Vegetation: Upland hardwood forest; black oaks, white oaks, and pine
Parent Material: Residuum from cherty limestone
Physiography: Nearly level to very steep upland ridgetops and sideslopes. Slopes range from 1 to 60%
Described and sampled by: L. B. Ward
Date: March 12, 1974

Table 5 . Sorption constants of metribuzin by two Captina soil horizons. These data are from Paetzold (1976).
Soil Horizon
Linear
Freundlich
Langmuir
 
m (Kd)
b
k
n
Smax
K1
Ap
0.46
1.87
0.49
1.04
-899.82
-0.0006
B2t
0.18
0.74
0.37
0.85
28.95
0.0124
Linear Model: S = mCS + b
Freundlich Model: S = kCSn
Langmuir Model: S = SmaxK1CS/(1 + K1CS)

Table 6. Variability of the soil properties in Captina-Johnsburg association in three horizons. (These data are from Wood et al. 1987).
Soil Property
Horizon
Minimum
Maximum
Mean
%CV
Water retained at the designated pressure        
 
10 kPa, kg kg-1
Ap
0.177
0.320
0.251
11.9
 
Bt
0.190
0.337
0.268
12.7
 
Btx
0.109
0.334
0.270
13.0
1500 kPa, kg kg-1
Ap
0.032
0.165
0.072
34.9
 
Bt
0.046
0.216
0.108
28.1
 
Btx
0.066
0.172
0.114
20.7
pH
Ap
4.3
7.9
5.8
10.2
 
Bt
4.2
7.1
5.6
11.2
 
Btx
3.7
8.0
5.1
12.1
Sand %
Ap
9.17
53.13
30.62
28.7
 
Bt
8.00
35.37
23.13
26.3
 
Btx
6.23
36.43
22.31
26.0
Silt %
Ap
38.13
76.27
56.85
13.9
 
Bt
37.37
81.40
53.69
15.0
 
Btx
37.67
78.70
51.57
14.5
Clay %
Ap
4.47
31.53
12.55
31.9
 
Bt
8.20
32.73
23.18
18.4
 
Btx
7.60
33.73
26.13
13.9
Kd, m3 kg-1 x 10-3
Ap
0.72
4.63
1.75
45.4
 
Bt
0.31
1.81
0.76
37.3
 
Btx
0.33
1.30
0.76
25.1
Organic matter, g kg-1
Ap
5.3
34.5
14.0
37.5
 
Bt
1.7
14.2
4.4
44.6
 
Btx
1.3
9.8
3.3
49.6
Koc, m3 kg-1 x 10-3
Ap
103.65
344.90
211.10
17.0
 
Bt
66.32
724.20
319.87
33.8
 
Btx
66.58
1445.00
466.57
47.1