March i, 1898,] 
THE TROPICAL AGRICULTURIST. 
59S 
SCIENTIFIC MANURING, 
One does not expect to find agricultural infor- 
mation, especially on that branch of agriculture 
which deals with the latest advances in the scien- 
tific treatment of the soil, in an ecclesiastical 
journal ; but the Guardian, one of the best edi 
ted and most influential organs of the Anglican 
Church, claims to be a religious paper in other than 
the ordinarily accepted sense. It is not entirtdy 
devoted to the discussion of religious questions. Its 
editorial notes, discussing the principal political 
topics of the week, are singularly well-written 
and judicial; and Mr. Gladstone has been quoted as 
having declared them to be among the best-written 
and fairest in current literature, though they are of 
late years decidedly Unionist in their tendency. 
The column articles are somewhat heavier, but are 
also well worth reading; and among these, at 
frequent intervals, is a paper of interest to the 
farmer, and ])resumably also to the country- 
clergyman, whose income still to a greac extent 
depends on the soil and its treatment. 'We have 
been interested by recent articles, which pre.sent 
the details of experiments with manure, 
after the most approved scientilic fashion, by 
comparing the yiehl of unmaniu'ed plots with 
manured ; experiments in poultry-keeping with 
details of cost ; in fattening cattle and pigs for 
the market all worked out with business-like 
accuracy, and generally tending to show how a 
limited income may be helped by small indus- 
tries which are at once interesting and con- 
ducive to health. In one of these issues, 
we have noted a very instructive article, 
dealing with recent discussions on manur- 
ing which has a bearing on much that is 
going on among ourselves, in view of the 
growing interest in fertilizing substances, and 
their projected application to the soil on scientilic 
principles. Proba'dy, the enterpri.se of Messrs. 
Ereiulenberg & Co. and Messrs. Raur d: Co. is not 
wholly unconnected with the movement in 
Germany to which the article refers. For, two 
topics to which sjiecial attention is drawn, witli 
a preliminary lament at the paucity of agri- 
culturists who reail what is intended for their 
banelit, are Hrst the inquiry by two eminent 
German Professors into the problem of combin- 
ing ordinary farmyard manure with certain arti- 
hcial manures — “notably timse contaitiing nitro- 
gen in the form of nitrate of soda ;” and 
second the success attending the use of basic 
slag to bott wheat and clover in some of the 
farms of the Midlands. The topics are not 
wholly new ; but we are not sure that we have 
ever seen the German conclu.sions so explicitly 
set forth, as going counter to accepted theories 
and practice. Not only is it claimed that the 
mixture of artificial and farmyard manures, as 
above described, leads to no improvement in 
the constituents but it is distinctly asserted that 
the combination detracts from the value of the 
separate manure.s ! The tlieory is that the 
“ denitrifying organisms ” in the farmyard 
manure reduce the nitric acid to its elements 
of free nitrogen and oxygen, and so render it 
incapable of serving as plant food. Superphosphate 
and kainic are said to inciease thi.s delet.-rious 
action, by giving vitality and ))ower to the 
denitrifying organisms. Professor Somerville 
of the Durham College of Science has 
found support for these conclusions in the ex- 
periments he had directed in the Nortli of 
England, where, in certain instances, th.e crop of 
turnips 'was actually diminishevl in Helds which 
73 
had a dressing of farm manure and super- 
phosphates ! We may note in this connection 
that in papers on scientific manuring recently cir- 
culated locally, there is a strong recommenda- 
tion that kainit, which is condemned above for 
mixing purposes, should be added to cattle or 
stable manure or daily sprinkled over heaps, as 
it “ has been proved to have the property, in a 
certain degree, of preventing loss of nitrogen from 
cattle manure” ! We know that on one estate 
at least on which Messr.s. Freudenberg’s manures 
are having a trial, kainit has been sprinkled 
over the usual combination of cattle manure 
and bones dug into the soil at the root of coco- 
nut trees ; and we hope to receive informa- 
tion , in due course, of any difterence that may 
be observed, in the appearance of tlie trees and 
in crop, between the fields thus treated, and 
those to which kainit has not been so applied. 
The German experiments go counter to more 
than the mixture of artificial and natural 
manures. Tliey are saiil to establish 
— the experiments were limited to pots, 
—that horse and cow dung added to 
the soil give a smaller crop than the unaided 
soil, and a mucli smaller crop than the 
soil assisted only with a dose of nitrate of 
soda containing the same amount of nitrogen 
as the dung. The writer in the Guardian, as 
we think rightly, refuses to accept this result 
as justifying distrust in the universal experi- 
ence and belief of farmers in favour of the use 
of the drojipings of animals to enrich the soil. 
The material used may have been too fresh, 
it may have been used in too large a quantity, 
or in its decomposition it may have had an 
untoward effect on the mechanical condition of 
the soil ; but it is important to note that various 
practical English fanners insist that dung does 
act injuriously, when it is used upon' grass 
ploughed up for an oat crop. In this instance, 
the article under notice suggests that the injury is 
probably due, not to “denitrification,” but to 
the ground “ being mechanically kept too open 
to allow the proper development of the roots, 
and retention of moisture oats requiring a 
good supply of moisture at every stage. 'What 
is of importance is, the knorvledge which these 
experiments supply, tl'at the best of manures, 
artilicial and natural, may not only do no good, 
but be positively hurtful, under certain con- 
ditions of soil or climate. It is only corelative 
to the experience in human beings, that what 
is food to one may be poison to another, and what 
is nourishing at one time may be fatally iju 
jurious at another. The conditions must be 
ascertained by experience, supplemented by 
science. 
In regard to the use of basic slag — which i.s, 
we believe, also known as Thomas’s Phosphate 
Powder, and which is obtained from iron ores 
rich in phosphorus, by the extraction of phos- 
jdtorie acid and the simultaneous addition of 
lime— its success uith wheat and clover has 
given it an immense reputation, and it is 
claimed that 50 bushels of wheat per acre and 
two tons of clover arc the certain result of the 
application of b c\i r. of basic slag, costinv^ 
about 12s. in .all. The Ouardiau writer states 
that inquiry has shown that these re-sults have 
been obt.ained where t e wheat itself, or the 
preceding crop, had received full dressings of 
common manure ; while the clover was grown on 
certain speci.al soil.s. Without in any way question- 
ing the value of basic slag, who.se richness in 
phos)ihorio acid, combined with free lime auti 
