VARIOUS rilOSPHATIC MANURES ON UPI.AND SOIL, 
7 
In harmony with the action of the phosphatic fertilizers on the 
produce of dry matter, we find from the above table that from the 
larger doses of phosphates invariably more phosphoric acid was 
consumed than from the smaller ones, wherefore the results 
obtained with the latter will yield reliable information also on the 
relative assimilability of the various forms of phosphoric acid. 
Assuming also here the quantity consumed from the superphos¬ 
phate (21.5) to be 100 and calculating on this basis the relative 
assimilability of other forms of phosphoric acid, we obtain the 
following results, to which we add for comparison the relative 
effect on the increase of dry matter. 
Relative Relative 
Relative effect on the manurial value, 
milability. increase of dry concerning the 
Double superphosphate. 
... 100 
matter. 
IOO 
first crop 
IOO 
Steamed bone dust . 
... 77-2 
80.1 
79 
Precipitated calcium phosphate 
... 64.2 
60.2 
62 
Crude bone dust . 
- 57-7 
54 5 
50 
Raw crushed bones. 
... 586 
53-7 
56 
Thomas phosphate. 
... 60.9 
48.5 
55 
Bone ash. 
••• 23.3 
19.6 
21 
The two series of figures on the assimilability and effect on the 
produce coincide tolerably well, with the one exception of these 
obtained by the Thomas phosphate. In the case of this, as well 
as the other somewhat slowly acting manures, the phosphoric 
acid rendered available by the gradual decomposition in the soil, 
entered the plants too late to influence to its full capacity the 
production of dry matter, wherefore the plants supplied with these 
phosphates became richer in phosphoric acid than those manured 
with the more easily assimilable superphosphate. The analysis 
show, indeed, that the crop produced with Thomas phosphate was 
the richest in phosphoric acid, it contained in the dry matter 
0.188 % ; next comes the content of 0.180 % in the crop with 
bone ash, 0.177 °° i' 1 that without any phosphate, 0.172 % in 
the crop with raw crushed bones, 0.168 % in that with pre¬ 
cipitated phosphate, 0.166 % with superphosphate, 0.165 % with 
Average calculated from the two preceding columns. 
