684 
Journal of Agricultural Research 
Vol. XI, No. 13 
of young clover hay contains 34.2 pounds of calcium. If all of this were 
converted to calcium carbonate, it would give 85.5 pounds. The excess 
lime in the clover- and lime-treated soils over the soil receiving no treat¬ 
ment except lime is 460 pounds. Oat straw, according to the same 
authority, contains 6 pounds of calcium per ton; or in terms carbonate, 
15 pounds. This accounts for only a small part of the excess carbonate 
in the oat-treated soils. 
In a consideration of this question all the potential bases and acids in 
the manures should be considered, for after fairly complete decomposi¬ 
tion the potassium, for instance, however originally combined with the 
organic material, would tend to combine either with an acid in the soil 
or with an acid from the organic material itself. This would relieve an 
equivalent amount of calcium carbonate from the necessity of having to 
neutralize acid. 
Bearing directly upon this are the data found in Table IV, which 
is adapted directly from Hopkins (3, p . 603). 
Table IV .—Quantity (in pounds) of the elements in 1 ton of the clover hay and oat straw 
(dry material) 
Material. 
Phos¬ 
phorus. 
Potas¬ 
sium. 
Magne¬ 
sium. 
Cal¬ 
cium. 
Sul¬ 
phur. 
Sodi¬ 
um. 
Chlo- 
rin. 
Oats. 
2.4 
7-7 
9.0 
29. 0 
27. 0 
34 - 6 
5 °. 6 
64.8 
2.8 
11. 7 
9-4 
39 - 1 
6 . O 
I 5 - 0 
34-2 
85.5 
I. 2 
3 - 7 
1.4 
4.4 
3 -o 
6- 5 
2.8 
6. 1 
5-4 
7.6 
6.6 
9-3 
Calcium carbonate equivalent. 
Clover. 
Calcium carbonate equivalent. 
In Table IV are given the pounds of the elements in clover hay and oat 
straw found in 1 ton. It should be noted that the values are for oat 
straw and not the immature oat plant which was used in this experiment. 
No data could be found for such material. In the table the calcium 
carbonate equivalent of the various elements appear. These were cal¬ 
culated on the supposition that the elements would be completely hydro¬ 
lyzed or oxidized to their respective bases or acids and would then 
neutralize an equivalent of acid, in the case of the base, or an equivalent 
of base, probably lime, in the case of the acids. For the oats the excess 
lime equivalent of the bases over the acids is 48.1 pounds, and for the 
clover 152.8 pounds. It should be noted that these numbers include in 
them the calcium carbonate equivalent of the calcium as mentioned 
above. This, then, does not account for all of the excess lime remaining 
in the green-manured soils, but it does, at least with the clover, account 
for an appreciable percentage of it. Therefore this excess lime must 
come from the calcium silicates, but this does not explain why there is 
a greater amount left in the manured than in the unmanured soils. 
Next to be considered are the values found in columns 7 and 8 of Table 
III. It is seen that in every case the lime causes an increased decom- 
