x88 
Journal of Agricultural Research 
Vol. XXV, No. 4 
greater in nearly every case on the unlimed plots. The reverse was 
true, however, in the case of Swedish turnips. 
The effect of liming on the loss in efficiency of phosphates evidently 
varies very considerably according to the character of the soil involved. 
In some soils, such as that of the Rhode Island Experiment Station, the 
influence of lime may be so pronounced on certain soil conditions affect¬ 
ing growth of particular crops as to mask entirely the effect of the lime 
on the efficiencies of the phosphates. This possibly may have been 
true in the case of soil No. 1529 where the efficiency of acid phosphate 
was markedly increased by liming. 
RATE AT WHICH PHOSPHATES LOSE EFFICIENCY IN THE SOIL 
In order to learn whether the losses in efficiency of phosphates remain¬ 
ing six weeks in the soil were about the maximum to be expected, or 
whether greater losses would have taken place had the phosphates been 
incorporated with the soil for a period longer than six weeks, supple¬ 
mentary experiments were conducted with four of the soils to secure 
data on the rate of loss. The experiments were conducted in the same 
manner as those previously described, except that in some tests 2-gallon 
glazed pots were used instead of 5-gallon containers. The essential 
details of the tests are given in Table X. 
Table X.— Conditions of Experiments X to XIV , inclusive. 
Experiment 
No. 
Soil 
No. 
Quantity 
of 
moisture- 
free soil 
per pot. 
Optimum 
water- 
content 
of soiL 
Sodium 
nitrate 
per pot. 
Ammoni¬ 
um sul¬ 
phate per 
pot. 
Potas¬ 
sium sul¬ 
phate per 
pot. 
Number 
of plants 
grown 
per pot 
Number 
of days 
plants 
grew. 
X 1 . 
213 
Kgm 
42. 07 
Per cent. 
18 
Gm. 
12. 6 
Gm. 
9. O 
Gm. 
12 . 0 
6 
35 
XI. 
1578 
17-31 
30 
3-2 
2-3 
3 - 0 
20 
42 
XII. 
1578 
6. 21 
30 
5-6 
4. 0 
5-3 
12 
33 
XIII. 
1529 
19. 98 
13 
4.2 
3 -o 
4.0 
l6 
41 
XIV. 
IS 2 4 
7. 80 
25 
3-5 
2-5 
3-3 
IO 
39 
1 In this experiment corn was grown instead of millet. 
Table XI gives the results of the experiments. 
The results of Experiment X show that, in some soils at least, the loss 
in efficiency which the phosphates undergo depends to a considerable 
extent upon the size of the application, the larger application losing 
much less of its efficiency than the smaller. This was one reason why 
in the other experiments there were applied quantities near the maxi¬ 
mum to which the soil would respond. 
As in the previous experiments, the losses in efficiency varied consid¬ 
erably, according to the kind of soil involved. The results on the whole 
indicated that acid phosphate continued to lose in efficiency the longer 
it remained in the soil, although the loss was exceedingly small after the 
first 20 to 30 days. This is illustrated in figure 1, the curve of which is 
a composite of the curves plotted from the results given in the unlimed 
series of Table IV, Experiment III, and Table XVI, Experiments X, XI, 
XII, XIII, and XIV. It does not, therefore, show the rate of loss in any 
one soil. In this curve the efficiencies of the acid phosphate applied at 
various lengths of time before planting are plotted relative to 100 for the 
