VARIATION IN THE CHEMICAL COMPOSITION OF SOILS. 5 
The method used for determining phosphorus was tested on 
synthetic mixtures, and as a result it is estimated that the figures 
given for phosphoric acid are within 0.02 per cent of the actual 
amount present. 
Blank determinations were made in all cases, and the silica and 
magnesia corrected for impurities. The quantity of silica in the 
iron and alumina group precipitate had been found constantly so 
small in earlier work that no correction was made for it here. 
RESULTS OF ANALYSES. 
The results of these analyses are given in the following table. 
The results are stated in percentage of the soil dried at 105° C. 
Table 1. — Chemical analyses of certain American soils. 
[Analyses by W. O. Robinson and L. A. Steinkoenig; nitrogen determinations by Wm. H. Fry.] 
Constituent. 
Si0 2 
Ti0 2 
A1 2 3 
Fe 2 3 
MnO 
CaO 
MgO 
K 2 
Na 2 
P 2 5 
S0 3 
N 
Loss on ignition 
Great Plains Province. 
Colorado sand. 
(1) 
0-14 
inches. 
P. ct. 
78.85 
0.32 
9.68 
2.72 
0.031 
0.94 
0.72 
2.31 
2.02 
0.11 
0.07 
0.10 
2.28 
(2) 
14-36 
inches. 
P. ct. 
76.84 
0.36 
11.09 
3.21 
0.036 
1.08 
0.62 
2.57 
2.06 
0.09 
0.20 
0.07 
2.35 
Oswego silt 
loam. 
(3) 
0-14 
inches. 
P. ct. 
71.38 
0.68 
12.29 
3.63 
0.056 
1.09 
0.36 
2.28 
1.14 
0.10 
0.12 
0.20 
7.11 
(4) 
14-36 
inches. 
P. ct. 
68.74 
0.70 
14.45 
5.00 
0.057 
0.88 
1.12 
2.20 
1.12 
0.08 
0.18 
0.13 
5.49 
Glacial and Loessial Province. 
Knox silt loam. 
(5) 
0-14 
inches. 
P. ct. 
76.81 
0.70 
9.73 
3.26 
0.068 
0.92 
0.60 
2.10 
1.74 
0.12 
0.11 
0.14 
4.09 
(6) 
14-36 
inches. 
P.ct. 
75.95 
0.70 
11.16 
3.99 
0.067 
0.92 
0.74 
1.60 
1.74 
0.10 
0.02 
0.06 
2.77 
Memphis silt 
loam. 
(7) 
0-6 
inches. 
P.ct. 
81.13 
0.78 
8.52 
2.92 
0.027 
0.31 
0.39 
1.78 
0.52 
0.08 
0.03 
0.11 
3.40 
(8) 
6-36 
inches. 
P.ct. 
73.58 
0.80 
12.25 
5.02 
0.067 
0.36 
0.78 
2.14 
0.71 
0.14 
0.02 
0.07 
4.01 
Memphis silt 
loam, smooth 
phase. 
(9) 
0-6 
inches. 
P.ct. 
80.78 
0.86 
8.48 
3.05 
0.036 
0.27 
0.45 
1.84 
0.72 
0.10 
0.03 
0.06 
3.20 
(10) 
6-36 
inches. 
P. ct. 
72.67 
0.79 
12.80 
5.58 
0.052 
0.26 
0.84 
2.08 
0.56 
0.13 
0.04 
0.05 
3.96 
Constituent. 
Si0 2 . 
Ti0 2 . 
ALOo 
F 4°3 
MnO. 
CaO.. 
MgO. 
KoO . 
Na 2 0. 
N.. 
Loss on igni- 
tion 
River Flood Plains Province. 
Cahaba fine 
sandy loam. 
(11) 
0-12 
inches. 
P.ct. 
91.39 
0.52 
3.72 
0.97 
0.065 
0.21 
0.09 
0.90 
0.12 
0.06 
0.06 
0.05 
1.53 
(12) 
12-36 
inches. 
P.ct. 
73.25 
0.69 
13.79 
4.88 
0.024 
0.15 
0.34 
1.08 
0-10 
0.05 
0.05 
0.10 
5.18 
Cahaba very 
fine sandy 
loam. 
(13) 
0-12 
inches. 
P.ct. 
93.29 
0.42 
2.45 
0.78 
0.066 
0.15 
0.01 
0.45 
0.03 
0.06 
0.10 
0.05 
(14) 
12-36 
inches. 
P.ct. 
91.83 
0.46 
3.83 
1.19 
0.079 
0.12 
0.09 
0.58 
0.05 
0.05 
0.13 
0.03 
2.12 1.61 2.33 0.79 
Coastal Plain Province. 
Norfolk sand. 
(15) 
0-8 
inches 
P.ct. 
94.81 
0.51 
1.42 
0.60 
0.028 
0.19 
0.01 
0.08 
0.12! 
0.10 
0.08 
0.05 
(16) 
8-36 
inches 
P.ct. 
97.01 
0.53 
1.31 
0.52 
0.005 
0.03 
0.01 
0.08 
0.08 
0.03 
0.06 
0.02 
Orangeburg 
sand. 
(17) 
0-10 
(18) 
10-36 
inches, 'inches. 
P.ct. 
96.18 
0.35 
1.70 
0.59 
0.016 
0.08 
Trace. 
0.0S 
Trace. 
0.04 
0.07 
0.06 
1.03 
P.ct. 
91.86 
0.41 
4.11 
1.32 
0.011 
0.05 
Trace. 
0.10 
Trace. 
0.04 
0.10 
0.02 
1.75 
Orangeburg 
sandy loam. 
(19) 
0-12 
inches. 
P.ct. 
94.32 
0.40 
2.13 
0.85 
0. 054 
0.05 
Trace. 
0.10 
0.29 
0.05 
0.07 
0.03 
1.69 
(20) 
12-36 
inches, 
P.ct. 
77.20 
0.66 
12.75 
3.18 
0.027 
0.09 
0.08 
0.14 
0.20 
0.08 
0.11 
0.08 
5. 19 2. 00 
Greenville 
sandy loam. 
(21) 
0-10 
inches, 
P.ct. 
92.42 
0.41 
2.78 
1.55 
0.030 
0.01 
Trace. 
0.13 
0.26 
0.05 
0.02 
0.02 
(22) 
10-36 
inches. 
P.ct. 
73.03 
0.70 
16.11 
5.11 
0.016 
0.10 
0.23 
0.14 
0.26 
0.06 
0.05 
0.03 
