Oct. I, i8(/7.] 
THE TROPICAL AGRICULTURIST. 
263 
^’oiiraspcndenc^. 
?/■ llif T.ili'of 
SALT IN AGRICULTURE. 
Kanily, 25111 October 1855. 
To the Secretary of the Planters’ Association, Kandy. 
SiH, — My attention for sometime has been given 
to the subject of employing common salt as an 
element in preparing fertilizers for coffee lands— 
and this subject I learn, is at present under con- 
sideration of Government, with the view chiefly of 
ascertaining whether some modification of the exist- 
ing revenue regulations respecting salt might not 
be effected for the purpose of rendering this ele- 
ment more available for use on estates for manure, 
and for food for stock. And as the value of common 
salt as a fertilizer either by itself, or when brought 
largely into use in combination with other materials, 
has by some scientific men in the island, been 
questioned in its applicability to coffee in particular 
and generally to intertropical culture, I have been 
led to bring the subject, through you and the press, 
to the notice of the planting community in the hope 
that this course may elicit opinions and lead to 
experiments which may throw valuable light upon a 
question of some interest to us all. 
Professor James F. W. Johnston, whose eminence 
as an Agricultural Chemist none will question, whose 
writings upon Agricultural Chemistry have been 
translated into every language of Europe, and some 
of whose works on the modern subject have been 
adopted as class-books, in many of the public schools, 
abroad and at home, is much in favor of the use 
of salt as a fertilizer. He has written a work on 
the use of salt in agriculture, which I regret not 
having, but upon referring to his other works I 
find much said upon the subject which I shall take 
the liberty of embodying in this communication 
making comments of my own as they occur, in relavion 
to considerations of a local character. 
Johnston says in his “ History of Fertilizers ” 
second edition: — “It would be difficult to name any 
other substance in the catalogue of fertilizers whose 
powers have been so often disputed as common 
salt.’’ But he adds, “ It has been generaliy employed 
with little scientific accuracy and in far too loose a 
manner for reliance to be placed upon reports upon 
its use. It is an agent which though employed in 
various agricultural operations from the earliest 
periods, has had to encounter many prejudices, 
obstacles and even prohibitions. Since the repeal of 
the duties in England the consumption by Farmers 
has rapidly increased. The examinations which 
have been carefully made of salt in the last ten 
years have demonstrated many important truths, 
dispelled much ignorant and absurd reasoning, and 
cleared the path for future investigators,” 
“ Common salt is composed, according to Dr. Marcet, 
ol Chlorine [a. gas of a greenish colour, and unpleasant 
taste, and a suffocating odour, which combining with 
other substances forms chlorides) 59J parts — and 
sodium, the metallic base of soda 40J parts. Its 
fertilizing properties when applied to land are — 
1st. — It promotes decomposition of animal and 
vegetable substances in all cultivated soils. 
2nd — It destroys vermin, kills weeds, &c., which 
are thus converted into manure. 
3rd. — It is a direct constituent or food of some 
lants. 
4th. — It acts on vegetable substances as a stimu- 
lant. — Dr. Priestly proved this by various interesting 
experiments shewing that while an overdose of salt- 
killed plants, a limited application in water kept 
them alive longer than those treated with water 
alone. A solution of chlorine in water will 
make certain seeds vegetate which would otherwise rot 
in the earth. 
S' 5th. — Salt preserves vegetables from injury by 
sudden transitions in the temperature of the at- 
mosphere. 
33 
i5th (and most important). — Salt renders earth 
move capable of absorbing the moisture of the 
atmosphere, a property of the first importance, since 
those soils which absorb the greatest proportion of 
moisture, are always the most valuable to the culti- 
vator. “ It affords” (said Davy, Agile. Chem. p. 
184) “ one method of judging of the productiveness 
of land.” The absorbent powers of common salt 
applied to land, are shewn by a table of experiments 
to be greater than those of six other well known 
manures. 
The coffee plant, like the gluten cereals, in its develop- 
ment and productive powers is barely affected by the 
nitrates, whether derived from the soil or from the 
atmosphere. Johnston says “ salt rarely causes the 
wheat (a gluten cereal) to grow larger or taller, but 
it fills the ear better, and brings the weak plants 
forward. On Mr. Sinclair’s anthoiily, salt appears 
to lessen the production of straw and increase the 
weight of grain. 
Soil without any manure for four years gavelS bushels 
weight per acre. 
Ditto with 5 bushels of salt per acre, and no other 
manure gave 20 bushels. 
Soil with 45 tons pit manure gave 49 bushels wheat 
per acre. 
Ditto with 44 bushels salt added gave 75 bushels 
per acre. 
Soil with 54 bushels salt and 5h bushels oil cake 
applied as manure gave Of bushels per acre. 
Soil without any manure produced 30 bushels of 
barley per acre. 
Ditto dressed with 10 bushels of salt per acre gave 
51 bushels of barley per acre. 
Sir Thomas Acland — August 1826 — considered salt 
a good manure for light soils, but not calculated for 
clay or heavy lands. 
Mr. Collyns Devonshire, whose farm is almost en- 
tirely a light black sand, writes, “ I have found 
salt answer my most sanguine expectations, both 
as to the increased quantity and improved quality 
of the crops. My barley and oats which used to 
yield only 15 to 20 bushels per acre, now yield 40 
to 45. In every field salted, I have found the grass 
very iiruch superior to any prodirced before the use 
of salt.” 
For potatoes (a starch plant) a great To- 
tham in Essex, with simple soil, the produce 
per acre was 120 bushels. Soil with 20 
bushels of salt 192 bushels — with 20 loads of 
ma ure, 219 bushels. Ditto with 20 bushels of salt 
added, 234 bushels. At Hollenden house, Kent — 
soil three-fourths sand, without any manure gave 
157 bushels, with salt 199 busle's With 8 bushels 
salt, and 30 bushels soot 240 bushels. This Agricul- 
turist adds “ of ten different manures, salt, a manure 
hitherto of an ambiguous character, is, (one only ex- 
cepted) superior to them all. The effect of the mixture 
of the salt and soot is remarkable.” 
Salt may be employed in gardens as a fertilizer 
with decided advantage, — in the case of some vegetables 
improving the crop by fifty per cent. A very 
small quantity of salt added to the water in 
which cauliflowers are placed adds considerably to 
their duration — it is a common custom with the 
importers of Exotic plants to dip cuttings into 
salt water. Before the adoption of this plan they 
almost Invariably perished on the passage. An 
eminent flin-ist Mr. Hogg of Paddington, says, “from 
the few experiments I have tried with salt as a 
Garden manure I am fully prepared to bear testimony 
to its usefulness.” 
Salt acts as a destroyer of grubs and like vermin. 
Mr. Burk in Hertfordshire used it on his land for 
the purpose of destroying worms and slugs, with 
which it was very much infested, and says in some 
fields this was the means of preventing the total 
destruction of the crop. There is other numerous 
testimony to the same effect. It is customary in 
most counties of England to apply salt and water as 
a steep to prevent the ravages of disease in wheat 
called smut. Recent experiments have suggested 
that it may even be of use when employed in large 
