82 
THE TROPICAL AGRICULTURIST. 
[Aug. 1, 1903, 
nomioal, becauss in additioa to supplying from 25 to 
27 per cent. - of phosphate of lime in a form sufii 
oiently Bolnbte to afford available pUnt food, it also 
snppliea an appreciable dressing dTcaustic lime. How 
beneficial small dressiug&.of alXaliuo ashes are may 
be inferred from the practice in India of burning the 
■tubbles after the remo-yal of the corn and previous to 
the usual rainfall. In this aountry the custom of 
collecting and burning the common cough grass 
(Triticum Eepens) ia to be highly commended _ as 
being riot only the most efiectual way of eradicating 
this troublesome weed, bnt as being a cheap means 
of supplying valuable alkaline ashes to the soil ; 
for these ashes materially assist that important 
bacterial action whereby the inert vegetable matter 
of the soil is converted into valuable fertilising com- 
pounds such as nitrates. 
A strong argument in favour of the utility of 
alkaline phosphatic manures is afforded by the fact 
that all the natural manures hitherto used in agri- 
culture are distinctly allialine . Thus farmyard manure 
in the efficacy of which farmers thoroughly believe, 
is alkaline, and its agricultural value depends , upon 
the' extent to which the nitrogen compounds are con- 
verted by proper fermentation into ammonia salts. 
Guano, especially the good old Chincha Peruvian 
quality, is strongly ammoniaoal. Bonedust, dried 
blood, 'woolen waste and shoddy, also soot, and 
lastly lime, are all more or less alkaline in their 
nature, and certainly not acid. Moreover, it is hardly 
necessary to repeat that basic slag is itself a striking 
instance of the utility of alkaline phosphate of lime 
as a manure for certain soils. Indeed it is not natural 
that manure should be acid, and the reason why 
ordinarv acid supeiphosphate has been beneficial 
to crop's grown on good arable land, is that the aci- 
dity of the manure has been absorbed or neutralised 
by the abundance of lime usually present in such 
soils. Obviously, where the soil is deficient in lime 
the acidity of superphosphate cannot be immediately 
absorbed, and harm may be done to the young 
rootlets of the plant. It would require a very heavy 
dressing of lime to saturate the soil so completely 
that every square inch of surface should always 
contain the necessary quantity of lime requisite to 
absorb the acid from every particle of manure that 
may be brought in contact with it- In other words 
it ia much more economical to add lime in small 
quantity to the manure for the purpose of imme- 
diate and complete neutralisation, than to add lime 
in large quantities and at long intervals to the soil 
in order to provide a wasteful excess of alkali for 
the absorption of a minute quaolily of acid. The 
necessity of relying upon a sufficiency of lime in 
the soil is entirely removed when using basic super- 
phosphate, as by the careful admixture of an excess 
of lime in its manufacture all acidity is removed 
and the manure may be applied, mixed directly with 
the seed without any danger of destroying the vitality 
of the same As a practical demonstration of the 
injurious effects produced by the continued annual 
application of acid salts, it is only necessary to refer 
to the report on the Woburn experiments by Dr 
Voelcker in the last number of the "Journal of 
the Eoyal Agricultural Society," in which a photo- 
graph is given of absolutely barren spots where the 
barley crop had entirely failed in consequence of 
the annual application of sulphate of ammonia to 
a ferruginous sandy soil. These barren spots were 
evidently due to the local accumulation of acid 
compounds and the absence of sufficient lime, for 
on the adjoining plot, which had received the same 
qusntity of ammonia salts annually, but had in 
addition received a dressing of lime, the barley was 
lookiugly thoroughly healthy, Ot^ such soils as that 
at Woburn, basic super, which in addition to phos- 
phates, supplies some caustic lime, will naturally 
be be more suitable than ordinaiy super, and when 
t is remembered that four-fifths of the former consists 
of ordinary superphosphate, the manufacturer will 
find it to his interest to supply the new manure. 
Indeed, on all light sandy ferruginous soils manu- 
facturers are at present in an awkward position, 
because acid manures being unsuitable it follows that 
alkaline manure, superior in its fertilising properties 
to basic slag, should bs supplied, as otherwise no 
practical opposition to the use of slag is available. 
Basi-e superphosphate has the advantage that it can 
be mixed with nitrate of soda without any fear 
that the valuable nitiic acid will be decomposed or 
driven oft' by an excess of acid, and the resulting con- 
compound is in an excellent dry powdery condition, 
admirably adapted to secure uniform distribn 
tion as a top dreseiag. During the season 1901 
the manure has been sold in 187 places iu England, 
72 in Scotland, and 13 in Ireland. Many of the 
deliveries so included were in quantities of 10 to 20 
tons, consigned to agents, so that the actual local 
trials have been still more numerous. The practical 
results obtained in the field have, notwithstanding 
the dry season, been most encouraging, and have 
fully realised the favourable opinion originally formed 
from the analytical results. 
CONCLUSION. 
In conclusion, it should be mentioned that basic 
superphosphate is not intended to supersede ordinary 
acid superphosphate upon soils containing plenty of 
lime, nor is it intended to take the place of well 
ground slag for application to damp sour land ; bnt 
it is rather intended to take an intermediate position 
between these two well known and most useful 
manures, and to be employed as a quick acting 
alkaline phosphate manure, specially useful as a 
spring dressing for crops grown upon soils that 
contain less than 1 per cent, of lime, the united 
acreage of which represent such a large area of the 
cultivated land in the United Kingdom. The utility 
of alkaline phosphate manures when applied to certain 
soils has already been practically demonstrated by 
the great success that has attended the use of basic, 
slag, notwithstanding its slow solubility, its frequently 
defective grinding, and recently, its reduced percen- 
tage of phosphate. If therefore a material of similar 
alkalinity, but of greately superior solubility, can be 
obtained in an unlimited quantity, and of uniform 
quality, it is reasonable to anticipate that basic 
superphosphate will prove to be a really useful aud 
most» valuable additional fertiliser. The time has 
come when manures should be adapted to the soil, 
rather than that the soil should adapt itself to the 
manure. Obviously, soils differing so much in their 
chemical composition and physical character, as 
chalk and clay, peat and sand, granite and gravel 
require different manures, in the same way as they 
require different cultivation and different kinds of 
crops. It is not scientific, it is not economical, and 
it cannot be to the advantage of the farmer, that 
one kind of manure should be sold for application 
to all kinds of soils. Acid manures may with ad- 
vantage be applied where there is plenty of lime, 
and alkaline manures may be more profitably ap- 
dlied where lime is deficient, 
DISCUSSION. 
The Chairman thought the Society was indebted to 
the reader of the paper for the way in which he had 
clearly placed before the audience the relative actions 
of various phosphatic manures when applied to 
different types of soil, and also for the fairness and 
candour with which he had stated the claims of the 
new substance of which he was the parent. Mr. 
Hughes had asked them to look upon the new manure 
as filling a gap which had been recognised to exist in 
the ordinary systems of manuring. It was well-known 
that on an ordinary chalky soil or on a loam of an 
alkaline nature superphosphates answered every pos- 
sible requirements of a manure to supply phosphates. 
It was also known that on a great number of soils 
