66 o 
Journal of Agricultural Research 
Vol. XI, No. 12 
in these regions are invariably acid in reaction. Frequently areas of 
dark-colored acid soils are found having an exceptionally high content 
of iron or aluminium, or both. Recently an opportunity was given to 
study the problem from a chemical standpoint, and the results obtained 
from the investigation are presented in this paper as a contribution to 
our knowledge of the soil acidity question. 
EXPERIMENTAL WORK 
Experiment i. —Twenty-nine samples of miscellaneous soils col¬ 
lected from the several glacial formations of Ingham County, Mich., 
were analyzed for calcium, iron, aluminium, and silicon by the solubil¬ 
ity method, using iV/5 hydrochloric acid. Averages of duplicate deter¬ 
minations are reported. The reaction of the soils was determined by 
means of litmus paper in contact with moist soil and also the Veitch 
qualitative test. The two methods gave similar results on these soils. 
A summary of the analytical results is given in Table I. 
Table I.— Soil classes and quantities of calcium , iron, and aluminium soluble in Nj$ 
hydrochloric acid 
ACID SOILS 
[Estimated as oxids. Results expressed as pounds per 2,000,000 pounds of soil] 
6 
7 
9 
10 
13 
14 
16, 
17 
20 
21 
22. 
23 
24. 
27 
28 
Laboratory No. 
Soil class. 
Sandy loam.. 
Loam. 
Sandy loam.. 
Medium sand 
_do. 
Sander loam.. 
Medium sand 
Clay loam.... 
Medium sand 
_do. 
Silt loam. 
Medium sand 
Sander loam.. 
_do. 
Calcium 
oxid. 
Iron oxid. 
Alumin¬ 
ium oxid. 
4,270 
3,010 
5,330 
2,390 
3,698 
3,894 
3,100 
3 , 
2,776 
i j 39 ° 
I, 462 
2, 288 
660 
1,892 
3 ,132 
2,270 
3,956 
2,144 
2,650 
3,612 
3,432 
960 
1,720 
2,450 
9,410 
4,000 
9 > 35<5 
1,300 
2,666 
3*076 
1,780 
2,332 
2,750 
4,170 
3,010 
3,100 
1,760 
2,708 
2,944 
4,140 
2,880 
2,952 
2, 040 
2, 706 
1,916 
3 , 7 io 
2,408 
3,294 
alkaline soils 
1. 
- 
Sandy loam. 
3 . 
.do. 
0 
A . 
Loam. 
*T . 
cr. . 
.do. 
D 
8. 
Silt loam. 
11. 
.do. 
12. 
Sandy loam. 
ic.. 
.... do. 
j . 
18. 
.do. 
.do... 
Silt loam. 
26. 
.do. 
29. 
Loam. 
10, 780 
2,966 
5,886 
8,840 
2,666 
3,220 
4,060 
3,182 
452 
4,750 
3,096 
530 
5 ,860 
3,440 
3,614 
8,140 
3,526 
4,298 
7,140 
3, *68 
4,062 
6, 210 
6,380 
2,966 
3, n8 
3,036 
2,838 
10,000 
36,000 
3,182 
2,988 
4,042 
9,406 
11,520 
2,924 
2,838 
5,041 
7,410 
4 , 3 10 
