COMPARATIVE EXPERIMENTS ON THE EFFECT OF 
2o 
B. Percentage of Phosphoric Acid Consumed by 
the Consecutive Crops. 
Length of action of the phosphates, 
months. 
7 
10 
20 
23 
Number of crops. 
First 
First 
First 
First 
crop. 
2 crops. 
3 crops. 
4 crops. 
Double superphosphate . 
21.5 
32.3 
395 
4°'3 
Steamed bone dust . 
16.6 
239 
3 I -5 
31.6 
Precipitated calcium phosphate 
13.8 
22.1 
O-i 
O 
bo 
31-3 
Crude bone dust. 
12.4 
23.1 
45-5 
48.4 
Raw crushed bones . 
12.6 
22.4 
38-9 
55-2 
Thomas phosphate . 
131 
16.2 
21.3 
21.5 
Bone ash . 
5 -° 
8.0 
16.2 
17.2 
C. Percentage of Phosphoric Acid Consumed per Months.* 
Length of action of the phosphates, 
months. 
7 
3 
IO 
3 
Kind of crops. 
ist crop. 
2nd crop. 
3rd crop. 
4th crop. 
Buck- 
Barley. 
Millet. 
Wheat. 
Wheat. 
Double superphosphate . 
31 
3-6 
0.7 
0-3 
Steamed bone dust . 
2.4 
2.4 
0.8 
003 
Precipitated calcium phosphate 
2.0 
2.8 
0.9 
0.1 
Crude bone dust. 
1.8 
3-6 
2.2 
1.0 
Raw crushed bones .. 
1.8 
3-2 
2.7 
2.1 
Thomas phosphate . 
1.9 
1.0 
0.5 
0.1 
Hone ash . 
0.7 
II 
0.8 
0.3 
* 1 lie figures in this table do not convey an entirely correct idea of the rapidity of 
action of the various phosphates, because the various crops did not grow with the same 
intensity. While the two winter crops (barley and wheat) are retarded in their growth 
during nearly 4 months, the summer crops (millet and buckwheat) attain their full develop¬ 
ment within 3 months. 
