July a8,1923 
Efficiency of Phosphatic Fertilizer 
175 
EFFICIENCIES OF THE PHOSPHATES AS AFFECTED BY THE SOII, 
Experiments I to VIII, inclusive, were similar in plan, but in each 
instance a different type of soil was used. The soil in half the series of 
pots in each experiment received sufficient lime to satisfy its require¬ 
ment by the Veitch method, and that in the remaining pots was left 
unlimed. The various phosphates were applied to some of the pots in 
both the limed and unlimed series six weeks before planting was done, 
and to the remainder the day before planting. The essential details of 
each of the eight experiments are given in Table III. 
Table III .—Conditions of Experiments I to VIII , inclusive 
Experiment No. 
Soil No. 
Quantity 
of mois¬ 
ture-free 
soil per 
pot. 
Opti¬ 
mum 
water 
content 
of soil. 1 
Sodium 
nitrate 
added 
per pot. 
Ammo¬ 
nium 
sulphate 
added 
per pot. 
Potas¬ 
sium 
sulphate 
added 
per pot. 
Number 
of plants 
grown 
per pot 
Number 
of days 
plants 
grew. 
Pounds. 
Per cent. 
Gm. 
Gm. 
Gm. 
I. 
1810 
$1.2 
40. O 
5*6 
4. O 
5-3 
15 
46 
II. 
1811 
37-9 
$0.0 
5-6 
4. O 
5-3 
15 
48 
Ill. 
1716 
42. 5 
12.3 
5*6 
4.0 
5-3 i 
14 
40 
IV. 
I 5 2 9 
41. 6 
13.O 
5-6 
4. O 
5-3 
18 
43 
V. 
1257 
42. 6 
22. O 
6.3 
4.5 
6. 0 
15 
38 
VI. 
1578 
37-8 
30. O 
5 * 3 
3-8 
5 - 0 
18 
43 
VII. 
1796 
3 1 * 1 
33 -o 
5-6 
4.0 
5*3 
14 
40 
VIII. 
1524 
41. 6 
29. 0 
8.4 
6. 0 
8.0 
21 
36 
1 Expressed in percentage of dry soil. 
Table IV shows the relative efficiencies of the various phosphates in 
both the limed and unlimed soils when the phosphates were applied 
immediately before and six weeks before planting. 
