VARIOUS PHOSI'HATIC MANURES ON UPLAND SOIL 
13 
crushed bones, and precipitated calcium phosphate have a value of 
about Yi, that of Thomas phosphate J-j, an d °f bone ash Y of that 
of superphosphate. Such a method, however, would not lead to 
quite a right idea as already mentioned, because the consumption 
may take place too late to enable the plant to make full use of the 
manure during its growth for the production of dry matter. Hence, 
it is more correct to take into account also the increase of the 
crop, and to deduce from the two series of results the relative value 
of the fertilizer. We get thus the following figures for the manuri- 
al values : 
Relative effect 
on the production 
of dry matter. 
Relative 
assimilability. 
Relative 
manorial value, 
ist & 2nd crop. 
Double superphosphate . 
100 
100 
100 
Steamed bone dust . 
81.0 
740 
77.5 
Precipitated calcium phosphate... 
66.6 
68.4 
«7.5 
Crude bone dust. 
67.0 
71-5 
69 
Raw crushed bones . 
<_rt 
CO 
Ln. 
69.4 
64 
Thomas phosphate . 
41.9 
50.2 
46 
Bone ash . 
23-3 
24.8 
24 
After the millet had been harvested, the soil of the cylinders was 
digged up, well mixed with the stubble and roots, and left in a 
loose condition until the 19th of the October, when per plot 1.413 
grams of nitrogen (50 kilograms, per hectare) were applied in the 
form of ammonium sulphate. Two days later wheat was sown 
with the help of the same perforated zinc plates which had already 
been used for the barley and millet. Where the seeds failed to 
germinate, new ones were sown a fortnight afterwards. During 
the winter the cylinders were again covered with mats every day 
from about sunset till the morning, but in spite of all care, . ome 
of the plots with the single dose of phosphoric acid in the form of 
Thomas phosphate and steamed bone dust were injured by frost.— 
On January 29th, 1892, 0.7065 grams of nitrogen as ammonium 
sulphate per plot (25 kilograms per hectare) was applied as a top 
manure, and this was repeated on the 23rd of March. The wheat 
was cut when nearly ripe on the 28th of June, and had the follow¬ 
ing weight (dry matter) per plot : 
