i6 
COMPARATIVE EXPERIMENTS ON THE EFFECT OF 
After the wheat had been harvested we cultivated as the 4th crop 
buckwheat with a supply of 75 kilograms per hectare of nitrogen 
in the form of ammonium sulphate. Sowing took place on 
the 19th of July. The development of this plant, like that of 
the millet in the preceding season, was rather inferior, as all 
assimilable phosphoric acid had been consumed by the wheat, the 
buckwheat thus depending on the small quantities which gradually 
became available through decomposition in the soil. On the 29th 
of September when the seeds were still green, we cut the plants. 
The yield of dry matter is shown by the following table : 
Phospho¬ 
ric acid 
in the 
original 
manure. 
grms. 
Yield. 
Dry 
matter. 
grms. 
Increase over the 
j plots not supplied 
1 with phosphoric acid. 
; 
Increase 
caused by 
, 100 grms. 
1 phosphoric 
acid, 
ist, 2nd, 
3rd, and 
4th crops, 
grms. 
j Grms. 
By joo 
grms. 
phospho¬ 
ric acid, 
grms. 
O 
No phosphatic manure ... 
9.1 
— 
— 
— 
1-413 
Double superphosphate... 
11.8 
2.7 
191 
24841 
2 826 
M tt 
13-5 
4-4 
156 
19816 
1.696 
Steamed bone dust.,, 
93 
0.2 
— 
(20805) 
3-392 
tt tt tt . 
14-3 
5-2 
153 j 
16303 
2.120 
Precipitated calcium phos. 
U.5 
2.4 
”3 
17865 
4 240 
ft tt tt 
22.6 
13-5 
319 
13326 
1.696 
Crude bone dust . 
22.7 
13.6 
802 
25412 
3-392 
tt tt tt . 
41.4 
32.3 
952 
22506 
1.696 
Raw crushed bones 
38.5 
29.4 
1734 
26652 
3-392 
tt tt tt 
53-9 
44.8 
1321 
20698 
2.120 
Thomas phosphate. 
II.I 
2.0 
95 
10577 
4 240 
tt tt . 
u .7 
2 6 
6l 
9818 
2.826 
Bone ash. 
11.8 
2.7 
96 
8631 
5.652 
tt tt . . %. 
13-5 
4-4 
79 1 
8018 
According to these results the relative increase caused by equal 
quantities of the various forms of phosphoric acid, is as follows : 
