July i, 1893.] THE TROPICAL AGRICULTURIST. 
PHOSPHORIC ACID TABLE. ■ • 
This table gives the weights of various manures per acre which will return to the soil 
phosphoric acid equal to that removed by two years' plucking, viz., 6 08 lbs., also to that removed 
by two years' plucking and pruning, viz., 13-63 lbs , together with the respective weights of nitrogen 
and poiash wliich accompany the i)hosphoiic acid in the manure. 
Description of Manuke. 
(1) 
(2) 
(3) 
W 
(5) 
(6) 
(7) 
(8) 
(9) 
10) 
(11) 
(12) 
(13) 
(14) 
(15) 
(16) 
(17) 
(18) 
(19) 
(20) 
Cattle 
1 
Manure No. 
No. 2 
Degelatinized Bone Meal 
Bone Dust or Meal ... 
,, Steamed 
Dissolved Bones 
Guano, Peruvian 
,, Equalised Peruvian 
Ichaboe 
,, Fish (superior) 
,, ,, (as sold in Ceylon).. 
,, ' Meat Meal Scrap 
Nuba Phosphate 
Precipitated,, 
Spanish Phosphorite 
Superphosphate (best) 
„ (good) 
,, (ordinary) 
Basic Slag (Thomas) 
Castor Cake (best) ... 
FoK Two Yeaes' Crops 
ONLY = 800 LBS. 
2,403 
6,609 
20-5 
26- 5 
27 
36-2 
38 'o 
43-5 
63 '4 
767 
118-2 
100-7 
14-8 
17-7 
20-3 
27- 2 
35-8 
43-4 
40-5 
209-7 
10-7 
42-6 
-4 
-9 
•7 
•8 
3-9 
3-2 
6- 9 
7- 3 
5-1 
5-1 
.14-7 
22-9 
70-6 
' ' -3 
' -3 
•9 
P'OR Two Years Crops and 
Prunings. 
2-62 
Weights of 
manures in lbs. 
which contain 
13-63 lbs. phos- 
phoric acid. 
lit of nit- 
1 in lbs, in 
lanure. 
ht of potash 
in manure. 
Weigl 
in lbs. 
5,452 
OA 'Q 
51-9 
14,812 
yo 4 
158-2 
46-2 
-8 
59-2 
2-1 
-6 
60-6 
1-6 
81-3 
1-9 
'"' -6 
86 2 
8-6 
2-9 
97-4 
7-1 
1-9 
142- 
15-3 
1-7 
171-9 
162 
264-7 
11-8 
226' 
11-4 
33-2 
39-7 
43-5 
el- 
se -2 
97- 
90-9 
470- 
'32-9 
"5 -.9 
Analyses (1) and ^2) see previous table. (3) Nl-8, P.,0=,.29-o. (4) N3-5, P^O^ 23. (5) N2-56 P,0 
22-5. (6) N2-H, P^Ojie-S. (7) to (12) .see previous table. (13) P2O541. (14) P, 05.34-3. (15) P,0, 30. 
(16) Sol P, 0,21-31. Total P,0,22'36. (17) Sol P,OJ5-5. Total P.O^n." (18) Sol P,0, 12-5. 
Total P2O5I4. (19) P.O3I5. 
Experience in manuring experiments generally, 
has not proved that the best results are obtained 
by returning plant food to the soil in exactly 
the proportions in which it is carried oil" in the 
crop, especially when manuring operations are 
delayed till the falling otf in crops demonstrates 
the "necessity for manure. It might possibly be 
otherwise if manuring were begun while estates 
were still in good heart before one or more of 
the constituents of plant food had been abnor- 
mally reduced. Not only do differences in the 
resources of the soil affect tlie question of manur- 
ing, but also different decrees of solubility, and 
therefore of availability of difierent kinds of plant 
food and even of different combinations of the 
same kind of plant food. 
The tal)les given will, therefore, not supersede 
the necessity for field experiments ; l)ut they 
will nevertheless afford useful data to the planter, 
as they will enable him to see more precisely 
• what he is doing in the way of manuring, and 
how he may compound equivalent mixtures of 
various manures so as (with the help of the 
valuation table vide Chapter on Manures) to take 
advantage of the cheapest and most suitable 
manures .available in the market. 
Although all the manures mentioned will be 
more fully treated of in <a subsequent Chapter, 
it may be well to explain here with reference 
to (Jeylon Cattle ^Manures No. 1 and No. 2 
mentioned in the tallies, that No. 1 was cattle 
nianure frcmi cattle led upon coconut poonac and 
guinea {jiass, the beddiuy being luana grass, 
while No. 2 was cattle manure from cattle fed 
upon guinea grass only, the bedding being luana 
grass. The former proved to be much the richer 
in phosphoric acid, while the latter had the 
advantage in respect of nitrogen and (being drier) 
had also rather more potash. The ])hosplioric 
acid in this manure, however, was so deficient 
compared witli No. 1 as to .suggest the advisability 
of supplementing cattle manure made from cattle 
fed upon grass only with phospliatic manure. 
In both samples of cattle nianure the propor- 
tion of potash was about double as gre<at.as is 
represented by certain well-known analyses of 
farmyard manure. 
I have said that experience of agricultural 
experiments has not proved that a nianure con- 
sisting of one theoretical dose of nitrogen, phos- 
phoric acid and potash respectively gives the best 
results, so that instead of starting a series of ex- 
periments in manuring tea with the strictly theo- 
retical dose, it would be preferable relying upon 
the known efficacy of good cattle manure, to 
begin by expressing the composition of good 
cattle manure in terms of theoretical doses of 
nitrogen, phosphoric acid and potash, and to .start 
with such as a standard ot comparison for a 
series of experiments. Doubtless careful planters 
are already acqii.ainted with the amount per acre 
of good cattle manure which j'ields satisfactory 
results, so in conducting experiments with com- 
mercial fertilisers it miglit be advisable to start 
with a mixture which contains the important 
elements of ^ilaut food in the same relative pro. 
