July 28,19 23 
Efficiency of Phosphatic Fertilizer 
187 
Table IX .—Efficiencies of the phosphates as affected by remaining 6 weeks in the soil 1 
Soil No.— 
Unlimed soil. 
Unlimed soil. 
Add 
phos¬ 
phate. 
Floats. 
Bone 
meal. 
Basic 
slag. 
Double 
super¬ 
phos¬ 
phate. 
Add 
phos¬ 
phate. 
Floats. 
Bone 
meal. 
Basic 
slag. 
Double 
super¬ 
phos¬ 
phate. 
*534. 
77 
120 
77 
56 
85 
63 
100 
85 
57 
68 
1578 . 
58 
90 
83 
61 
56 
61 
100 
63 
63 
60 
M 57 . 
48 
109 
75 
73 
66 
74 
167 
103 
138 
no 
1810.. 
61 
94 
X02 
40 
53 
62 
250 
57 
35 
x8n. 
57 
87 
9 i 
80 
67 
56 
80 
66 
73 
80 
1716. 
79 
88 
83 
X12 
93 
88 
335 
119 
123 
96 
1539 . 
75 
20 
85 
83 
63 
59 
100 
85 
64 
39 
1796 . 
49 
54 
56 
54 
53 
54 
67 
70 
74 
74 
art... t __ 
54 
50 
77 
Average *. 
63 
83 
82 
70 
67 
65 
140 
81 
78 
75 
1 The efficiency of each phosphate, applied immediately before planting to the limed or ttnlimed soil, 
is taken as 100; and the efficiency of each phosphate applied 6 weeks before planting, is expressed 
comparatively. 
1 Soil No. 213 not included. 
Incorporation of the phosphates with the soil six weeks before planting 
diminished the efficiencies of the five phosphates very appreciably in 
practically all soils whether lime was used or not. 6 The mean values for 
the different phosphates show that on the whole acid phosphate possibly 
lost slightly more of its efficiency than did double superphosphate or 
basic slag in both the unlimed and the limed series. Although bone meal 
and floats lost still less than did double superphosphates or basic slag, all 
these materials had a well defined tendency to be less, rather than more, 
efficient when they were applied six weeks in advance of planting. This 
is not in accord with the commonly expressed idea that floats and bone 
meal may be applied before planting is done because their availabilities 
increase with time. 
On the whole, liming did not appreciably affect the losses in efficiency 
sustained by the various phosphates when the latter were incorporated 
with the soil. The average results obtained with all the soils indicate 
that possibly liming diminished the losses of basic slag and double super¬ 
phosphates very slightly. The differences between the losses in the 
limed and the unlimed series in the case of these two phosphates, how¬ 
ever, are probably no greater than the experimental error. 
From these data it would seem that, in judging whether lime should 
be applied for the sake of its effect on the phosphates, the effect of lime 
on the immediate efficiency of the phosphate should be considered 
chiefly. 
These results are not in accord with the statement, which has gained 
authority from constant repetition, that liming tends to maintain the 
availabilities of phosphatic fertilizers. The results obtained by Wheeler 
(52) on the after effects of certain phosphates on limed and unlimed soil 
are to some extent confirmatory of the results reported in this paper. 
In the field experiments of Wheeler it will be noted that while the total 
yields of millet and potatoes were far greater on the limed than on the 
unlimed plots, the increases attributable to the phosphates were much 
s The results for floats in the limed soils are hardly significant. Liming alone reduced the efficiency of 
thia material to such a low figure that the added effect of remaining in the soil could not be measured with 
accuracy. 
