May si, 1917 Solubility of Certain Inorganic Soil Constituents 263 
Table IX .—Amounts of soil minerals removed from soils by solutions of artificial humus 
or hydrolyzed organic substances 
[Results expressed as parts per million of dry soil. Amounts removed by distilled water have been de¬ 
ducted] 
Source of humus. 
Or¬ 
ganic 
mat¬ 
ter 
in 
sol¬ 
vent. 
Clay-loam soil. 
Sandy-loam soil. 
Iron. 
Cal¬ 
cium. 
Magne¬ 
sium. 
Phos¬ 
phoric 
add. 
Iron. 
Cal- 
tium. 
Magne¬ 
sium. 
Phos¬ 
phoric 
add. 
Per ct. 
0.005 
. 02 
.04 
. to 
.ot 
.03 
.005 
.02 
.04 
. 01 
.03 
. 10 
.01 
.03 
.005 
. 02 
.04 
• 10 
0.05 
.19 
. 22 
XI. 64 
— . 22 
. 14 
— .09 
— .08 
— . 11 
. 16 
.09 
•39 
. 22 
.80 
.09 
• 23 
.48 
8.64 
0 
20 
38 
98 
9 
26 
2 
12 
22 
1 
18 
66 
160 
242 
10 
45 
S 3 
48 
Barley hay. 
Sweet-clover hay. 
—o* 08 
.06 
.06 
.02 
. 21 
.28 
•25 
.87 
— .08 
. 20 
.29 
108 
8 
as 
12 
35 
65 
— 4 
34 
94 
56 
IS® 
33 
9 
20 
21 
— 8 
2 
2 
0 
S 
22 
3 
2 
Alfalfa hay. 
Q11 era t* 
2 
6 
S 
12 
8 
9 
33 
16 
49 
5 
0 
— 2 
pUgdl.... 
■* 
Horse manure. 
I. 72 
Ii 5 
19 
S 3 
3 
81 
Like the organic extracts of the freshly decomposing green manures, 
these hydrolyzed humus solutions were neutral to phenolphthalein and 
methyl orange. They required, however, about the same amount of 
hydrochloric acid as did the above-mentioned organic extracts, in order 
to show an acid reaction witfi methyl orange. 
SOLVENT ACTION IN SOILS OF DECOMPOSING GREEN MANURES 
In the study of the humification of organic substances in soils in pots, 
several kinds of green-manure substances were used, and to some of 
these pots certain inorganic salts were also added. These soils were kept 
moist and stirred occasionally. Samples were extracted with distilled 
water and the extracts analyzed for the mineral elements discussed in 
the preceding work. Table X shows the results obtained in one of these 
experiments after the organic matter had been in contact with the soil 
for six months. The alfalfa was slightly more effective in bringing the 
soil minerals into solution than the manure. 
Table XI shows the results from a similar experiment with lighter 
soils, in which the organic matter had been in contact with the soil for 
three months. In this case the sweet clover did not exert as pronounced 
a solvent action as the manure. An increasing solvent action is shown 
with an increasing amount of organic matter. 
