DIFFERENT KINDS OF MANURE.
COW-MANURE, AND HOW TO USE IT.
“It will do more good if fermented,” said a German farmer in the
neighborhood, who is noted for raising good crops of cabbage, “but I
like hog-manure better than cow-dung. The right way is to mix the
hog-manure, cow-dung, and horse-manure together.”
“No doubt about that,” said I, “but when you have a good many cows, and
few other animals, how would you manage the manure?”
“I would gather leaves and swamp-muck, and use them for bedding the cows
and pigs. Leaves make splendid bedding, and they make rich manure, and
the cow-dung and leaves, when made into a pile, will ferment readily,
and make grand manure for--anything. I only wish I had all I could use.”
There is no question but what cow-manure is better if fermented, but it
is not always convenient to pile it during the winter in such a way that
it will not freeze. And in this case it may be the better plan to draw
it out on to the land, as opportunity offers.
“I have heard,” said Charley, “that pig-manure was not good for cabbage,
it produces ‘fingers and toes,’ or club-foot.”
Possibly such is the case when there is a predisposition to the disease,
but our German friend says he has never found any ill-effects from its
use.
“Cows,” said the Doctor, “when giving a large quantity of milk, make
rather poor manure. The manure loses what the milk takes from the food.”
“We have shown what that loss is,” said I. “It amounts to less than I
think is generally supposed. And in the winter, when the cows are dry,
the manure would be as rich as from oxen, provided both were fed alike.
See Appendix, page 342. It will there be seen that oxen take out only
4.1 lbs. of nitrogen from 100 lbs. of nitrogen consumed in the food. In
other words, provided there is no loss, we should get in the liquid and
solid excrements of the ox and dry cow 95.9 per cent of the nitrogen
furnished in the food, and a still higher per cent of the mineral
matter.”
SHEEP-MANURE.
According to Prof. Wolff’s table of analyses, sheep-manure, both solid
and liquid, contain less water than the manure from horses, cows, or
swine. With the exception of swine, the solid dung is also the richest
in nitrogen, while the urine of sheep is pre-eminently rich in nitrogen
and potash.
These facts are in accordance with the general opinions of farmers.
Sheep-manure is considered, next to hen-manure, the most valuable manure
made on the farm.
I do not think we have any satisfactory evidence to prove that 3 tons of
clover-hay and a ton of corn fed to a lot of fattening-sheep will afford
a quantity of manure containing any more plant-food than the same kind
and amount of food fed to a lot of fattening-cattle. The experiments of
Lawes & Gilbert indicate that if there is any difference it is in favor
of the ox. See Appendix, page 343. But it may well be that it is much
easier to save the manure from the sheep than from the cattle. And so,
practically, sheep may be better manure-makers than cattle--for the
simple reason that less of the urine is lost.
“As a rule,” said the Doctor, “the dung of sheep contains far less water
than the dung of cattle, though when you slop your breeding ewes to make
them give more milk, the dung differs but little in appearance from that
of cows. Ordinarily, however, sheep-dung is light and dry, and, like
horse-dung, will ferment much more rapidly than cow or pig-dung. In
piling manure in the winter or spring, special pains should be used to
mix the sheep and horse-manure with the cow and pig-manure. And it may
be remarked that for any crop or for any purpose where stable-manure is
deemed desirable, sheep-manure would be a better substitute than cow or
pig-manure.”
MANURE FROM SWINE.
The dry matter of hog-manure, especially the urine, is rich in nitrogen,
but it is mixed with such a large quantity of water that a ton of
hog-manure, as it is usually found in the pen, is less valuable than a
ton of horse or sheep-manure, and only a little more valuable than a ton
of cow-manure.
As I have before said, my own plan is to let the store-hogs sleep in a
basement-cellar, and bed them with horse and sheep-manure. I have this
winter over 50 sows under the horse-stable, and the manure from 8 horses
keeps them dry and comfortable, and we are not specially lavish with
straw in bedding the horses.
During the summer we aim to keep the hogs out in the pastures and
orchards as much as possible. This is not only good for the health of
the pigs, but saves labor and straw in the management of the manure. It
goes directly to the land. The pigs are good grazers and distribute the
manure as evenly over the land as sheep--in fact, during hot weather,
sheep are even more inclined to huddle together under the trees, and by
the side of the fence, than pigs. This is particularly the case with the
larger breeds of sheep.
In the winter it is not a difficult matter to save all the liquid and
solid excrements from pigs, provided the pens are dry and no water comes
in from the rain and snow. As pigs are often managed, this is the real
difficulty. Pigs void an enormous quantity of water, especially when fed
on slops from the house, whey, etc. If they are kept in a pen with a
separate feeding and sleeping apartment, both should be under cover, and
the feeding apartment may be kept covered a foot or so thick with the
soiled bedding from the sleeping apartment. When the pigs get up in a
morning, they will go into the feeding apartment, and the liquid will be
discharged on the mass of manure, straw, etc.
“Dried muck,” said the Deacon, “comes in very handy about a pig-pen, for
absorbing the liquid.”
“Yes,” said I, “and even dry earth can be used to great advantage, not
merely to absorb the liquid, but to keep the pens sweet and healthy. The
three chief points in saving manure from pigs are: 1, To have the pens
under cover; 2, to keep the feeding apartment or yard covered with a
thick mass of strawy manure and refuse of any kind, and 3, to scatter
plenty of dry earth or dry muck on the floor of the sleeping apartment,
and on top of the manure in the feeding apartment.”
“You feed most of your pigs,” said the Deacon, “out of doors in the
yard, and they sleep in the pens or basement cellars, and it seems to me
to be a good plan, as they get more fresh air and exercise than if
confined.”
“We do not lose much manure,” said I, “by feeding in the yards. You let
a dozen pigs sleep in a pen all night, and as soon as they hear you
putting the food in the troughs outside, they come to the door of the
pen, and there discharge the liquid and solid excrements on the mass of
manure left there on purpose to receive and absorb them. I am well aware
that as pigs are often managed, we lose at least half the value of their
manure, but there is no necessity for this. A little care and thought
will save nearly the whole of it.”
BUYING MANURE BY MEASURE OR WEIGHT.
The Deacon and I have just been weighing a bushel of different kinds of
manure made on the farm. We made two weighings of each kind, one thrown
in loose, and the other pressed down firm. The following is the result:
Weight of Manure per Bushel, and per Load of 50 Bushels.
Wt/Bu Weight per Bushel in lbs.
Wt/Load Weight per Load of 50 bushels.
---+--------------------------------------------+-------+---------
No.| Kind And Condition Of Manures. | Wt/Bu | Wt/Load
---+--------------------------------------------+-------+---------
| | lbs. | lbs.
1.|Fresh horse-manure free from straw | 37½ | 1875
2.| ” ” ” ” ” ” pressed | 55 | 2750
3.|Fresh horse-manure, | |
| as used for bedding pigs | 28 | 1400
4.| ” ” ” | |
| ” ” ” ” ” pressed | 46 | 2300
5.|Horse-manure from pig cellar | 50 | 2500
6.| ” ” ” ” ” pressed | 72 | 3600
7.|Pig-manure | 57 | 2850
8.| ” ” pressed | 75 | 3750
9.|Pig-manure and dry earth | 98 | 4900
10.|Sheep-manure from open shed | 42 | 2100
11.| ” ” ” ” ” pressed | 65 | 3250
12.|Sheep-manure from closed shed | 28 | 1400
13.| ” ” ” ” ” pressed | 38 | 1900
14.|Fresh cow-dung, free from straw | 87 | 4350
15.|Hen-manure | 34 | 1700
16.| ” ” pressed | 48 | 2400
---+--------------------------------------------+-------+---------
“In buying manure,” said the Deacon, “it makes quite a difference
whether the load is trod down solid or thrown loosely into the box.
A load of fresh horse-manure, when trod down, weighs half as much again
as when thrown in loose.”
“A load of horse-manure,” said Charley, “after it has been used for
bedding pigs, weighs 3,600 lbs., and only 2,300 lbs. when it is thrown
into the pens, and I suppose a ton of the ‘double-worked’ manure is
fully as valuable as a ton of the fresh horse-manure. If so, 15 ‘loads’
of the pig-pen manure is equal to 24 ‘loads’ of the stable-manure.”
“A ton of fresh horse-manure,” said the Doctor, “contains about 9 lbs.
of nitrogen; a ton of fresh cow-dung about 6 lbs.; a ton of fresh
sheep-dung, 11 lbs., and a ton of fresh pig-manure, 12 lbs. But if the
Deacon and you weighed correctly, a ‘load’ or cord of cow-manure would
contain more nitrogen than a load of pressed horse-manure. The figures
are as follows:
A load of 50 bushels of fresh horse-dung,
pressed and free from straw contains 12.37 lbs. nitrogen.
A load of fresh cow-dung 13.05 ” ”
” ” sheep ” 10.45 ” ”
” ” pig ” 22.50 ” ”
“These figures,” said I, “show how necessary it is to look at this
subject in all its aspects. If I was buying manures _by weight,_ I would
much prefer a ton of sheep-manure, if it had been made under cover, to
any other manure except hen-dung, especially if it contained all the
urine from the sheep. But if buying manure by the load or cord, that
from a covered pig-pen would be preferable to any other.”
LIQUID MANURE ON THE FARM.
I have never had any personal experience in the use of liquid manure to
any crop except grass. At Rothamsted, Mr. Lawes used to draw out the
liquid manure in a water-cart, and distribute it on grass land.
“What we want to know,” said the Deacon, “is whether the liquid from our
barn-yards will pay to draw out. If it will, the proper method of using
it can be left to our ingenuity.”
According to Prof. Wolff, a ton of urine from horses, cows, sheep, and
swine, contains the following amounts of nitrogen, phosphoric acid, and
potash, and, for the sake of comparison, I give the composition of
drainage from the barn-yard, and also of fresh dung of the different
animals:
Table Showing the Amount of Nitrogen, Phosphoric Acid, and Potash,
in One Ton of the Fresh Dung and Fresh Urine of Different Animals,
and Also of the Drainage of the Barn-Yard.
Nitro(gen).
Phos(phoric) Acid.
Pot(ash).
---------------+----------------------+-----------------------
| 1 Ton Fresh Dung. | 1 Ton Fresh Urine.
---------------+-------+-------+------+-------+-------+-------
|Nitro. |Phos. | Pot. |Nitro. |Phos. | Pot.
| |acid. | | |acid. |
---------------+-------+-------+------+-------+-------+-------
| lbs. | lbs. | lbs. | lbs. | lbs. | lbs.
Horse | 8.8 | 7.0 | 7.0 | 31.0 | | 30.0
Cow | 5.8 | 3.4 | 2.0 | 11.6 | | 9.8
Sheep | 11.0 | 6.2 | 3.0 | 39.0 | 0.2 | 45.2
Swine | 12.0 | 8.2 | 5.2 | 8.6 | 1.4 | 16.6
Mean | 9.4 | 6.2 | 4.3 | 22.5 | 0.4 | 25.4
Drainage of | | | | | |
barn-yard | | | | 3.0 | 0.2 | 9.8
---------------+-------+-------+------+-------+-------+-------
The drainage from a barn-yard, it will be seen, contains a little more
than half as much nitrogen as cow-dung; and it is probable that the
nitrogen in the liquid is in a much more available condition than that
in the dung. It contains, also, nearly five times as much potash as the
dung. It would seem, therefore, that with proper arrangements for
pumping and distributing, this liquid could be drawn a short distance
with profit.
But whether it will or will not pay to cart away the drainage, it is
obviously to our interest to prevent, as far as possible, any of the
liquid from running to waste.
It is of still greater importance to guard against any loss of urine. It
will be seen that, on the average, a ton of the urine of our domestic
animals contains more than twice as much nitrogen as a ton of the dung.
Where straw, leaves, swamp-muck, or other absorbent materials are not
sufficiently abundant to prevent any loss of urine, means should be used
to drain it into a tank so located that the liquid can either be pumped
back on to the manure when needed, or drawn away to the land.
“I do not see,” said the Deacon, “why horse and sheep-urine should
contain so much more nitrogen and potash than that from the cow and
pig.”
“The figures given by Prof. Wolff,” said I, “are general averages. The
composition of the urine varies greatly. The richer the food in
digestible nitrogenous matter, the more nitrogen will there be in the
dry matter of the urine. And, other things being equal, the less water
the animal drinks, the richer will the urine be in nitrogen. The urine
from a sheep fed solely on turnips would contain little or no more
nitrogen than the urine of a cow fed on turnips. An ox or a dry cow fed
on grass would probably void no more nor no poorer urine than a horse
fed on grass. The urine that Mr. Lawes drew out in a cart on to his
grass-land was made by sheep that had one lb. each of oil-cake per day,
and one lb. of chaffed clover-hay, and all the turnips they would eat.
They voided a large quantity of urine, but as the food was rich in
nitrogen, the urine was doubtless nearly or quite as rich as that
analyzed by Prof. Wolff, though that probably contained less water.”
If I was going to draw out liquid manure, I should be very careful to
spout all the buildings, and keep the animals and manure as much under
cover as possible, and also feed food rich in nitrogen. In such
circumstances, it would doubtless pay to draw the urine full as well as
to draw the solid manure.
NIGHTSOIL AND SEWAGE.
The composition of human excrements, as compared with the mean
composition of the excrements from horses, cows, sheep, and swine, so
far as the nitrogen, phosphoric acid, and potash are concerned, is as
follows:
Table Showing the Amount of Nitrogen, Phosphoric Acid, and Potash,
in One Ton of Fresh Human Excrements, and in One Ton of Fresh
Excrements From Horses, Cows, Sheep, and Swine.
Phos(phoric) Acid.
-----------+----------------------------+----------------------------
| Solids | Urine
One ton +---------+---------+--------+---------+--------+---------
(2000 lbs).| | Phos. | | | Phos. |
|Nitrogen.| acid. |Potash. |Nitrogen.| acid. |Potash.
-----------+---------+---------+--------+---------+--------+---------
Human |20.0 lbs.|21.8 lbs.|5.0 lbs.|12.0 lbs.|3.7 lbs.| 4.0 lbs.
-----------+---------+---------+--------+---------+--------+---------
Mean of | | | | | |
horse, cow,| | | | | |
sheep, and | | | | | |
swine | 9.4 ” | 6.2 ” |4.3 ” |22.5 ” |0.4 ” |25.4 ”
-----------+---------+---------+--------+---------+--------+---------
One ton of fresh fæces contains more than twice as much nitrogen, and
more than three times as much phosphoric acid, as a ton of fresh mixed
animal-dung. The nitrogen, too, is probably in a more available
condition than that in common barnyard-dung; and we should not be far
wrong in estimating 1 ton of fæces equal to 2½ tons of ordinary dung, or
about equal in value to carefully preserved manure from liberally-fed
sheep, swine, and fattening cattle.
“It is an unpleasant job,” said the Deacon, “but it pays well to empty
the vaults at least twice a year.”
“If farmers,” said the Doctor, “would only throw into the vaults from
time to time some dry earth or coal ashes, the contents of the vaults
could be removed without any disagreeable smell.”
“That is so,” said I, “and even where a vault has been shamefully
neglected, and is full of offensive matter, it can be cleaned out
without difficulty and without smell. I have cleaned out a large vault
in an hour. We were drawing manure from the yards with three teams and
piling it in the field. We brought back a load of sand and threw half of
it into the vault, and put the other half on one side, to be used as
required. The sand and fæces were then, with a long-handled shovel,
thrown into the wagon, and drawn to the pile of manure in the field, and
thrown on to the pile, not more than two or three inches thick. The team
brought back a load of sand, and so we continued until the work was
done. Sand or dry earth is cheap, and we used all that was necessary to
prevent the escape of any unpleasant gases, and to keep the material
from adhering to the shovels or the wagon.”
“Human urine,” said the Doctor, “is richer in phosphoric acid, but much
poorer in nitrogen and potash than the urine from horses, cows, sheep,
and swine.”
“Some years ago,” said the Deacon, “Mr. H. E. Hooker, of Rochester, used
to draw considerable quantities of urine from the city to his farm. It
would pay better to draw out the urine from farm animals.”
“The figures given above,” said I, “showing the composition of human
excrements, are from Prof. Wolff, and probably are generally correct.
But, of course, the composition of the excrements would vary greatly,
according to the food.”
It has been ascertained by Lawes and Gilbert that the amount of matter
voided by an adult male in the course of a year is--fæces, 95 lbs.;
urine, 1,049 lbs.; total liquid and solid excrements in the pure state,
1,144 lbs. These contain:
Dry substance--fæces, 23¾ lbs.; urine, 34½; total, 58¼ lbs.
Mineral matter--fæces, 2½ lbs.; urine, 12; total, 14½ lbs.
Carbon--fæces, 10 lbs.; urine, 12; total 22 lbs.
Nitrogen--fæces, 1.2 lbs.; urine, 10.8; total, 12 lbs.
Phosphoric acid--fæces, 0.7 lbs.; urine, 1.93; total, 2.63 lbs.
Potash--fæces, 0.24 lbs.; urine, 2.01; total, 2.25 lbs.
The amount of potash is given by Prof. E. Wolff, not by Lawes and
Gilbert.
The mixed solid and liquid excrements, in the condition they leave the
body, contain about 95 per cent of water. It would require, therefore,
20 tons of fresh mixed excrements, to make one ton of _dry_ nightsoil,
or the entire amount voided by a mixed family of 43 persons in a year.
One hundred lbs. of fresh fæces contain 75 lbs. of water, and 25 lbs. of
dry substance.
One hundred lbs. of fresh urine contain 96½ lbs. of water, and 3½ lbs.
of dry substance.
One hundred lbs. of the dry substance of the fæces contain 5 lbs. of
nitrogen, and 5½ lbs. of phosphates.
One hundred lbs. of the dry substance of the urine contain 27 lbs. of
nitrogen, and 10¾ lbs. of phosphates.
These figures are from Lawes and Gilbert, and may be taken as
representing the composition of excrements from moderately well-fed
persons.
According to Wolff, a ton of fresh human urine contains 12 lbs. of
nitrogen. According to Lawes and Gilbert, 18 lbs.
The liquid carted from the city by Mr. Hooker was from well-fed adult
males, and would doubtless be fully equal to the figures given by Lawes
and Gilbert. If we call the nitrogen worth 20 cents a lb., and the
phosphoric acid (soluble) worth 12½ cents, a ton of such urine would be
worth, _on the land_, $1.06.
“A ton of the fresh fæces,” said the Deacon, “at the same estimate,
would be worth (20 lbs. nitrogen, at 20 cents, $4; 21¾ lbs. phosphoric
acid, at 12½ cents, $2.70), $6.70.”
“Not by a good deal,” said the Doctor. “The nitrogen and phosphoric acid
in the urine are both soluble, and would be immediately available. But
the nitrogen and phosphoric acid in the fæces would be mostly insoluble.
We cannot estimate the nitrogen in the fæces at over 15 cents a lb., and
the phosphoric acid at 5 cents. This would make the value of a ton of
fresh fæces, _on the land_, $4.09.”
“This makes the ton of fæces worth about the same as a ton of urine. But
I would like to know,” said the Deacon, “if you really believe we could
afford to pay $4 per ton for the stuff delivered on the farm?”
“If we could get the genuine article,” said the Doctor, “it would be
worth $4 a ton. But, as a rule, it is mixed with water, and dirt, and
stones, and bricks, and rubbish of all kinds. Still, it is
unquestionably a valuable fertilizer.”
“In the dry-earth closets,” said I, “such a large quantity of earth has
to be used to absorb the liquid, that the material, even if used several
times, is not worth carting any considerable distance. Dr. Gilbert found
that 5 tons of absolutely dry earth, before using, contained 16.7 lbs.
of nitrogen.
After being used _once_, 5 tons of the dry earth contained 24.0 lbs.
” ” ” twice, ” ” ” ” ” 36.3 ”
” ” ” three times, ” ” ” ” ” 44.6 ”
” ” ” four times, ” ” ” ” ” 54.0 ”
” ” ” five times, ” ” ” ” ” 61.4 ”
” ” ” six times, ” ” ” ” ” 71.6 ”
Dr. Vœlcker found that five tons of dry earth gained about 7 lbs. of
nitrogen, and 11 lbs. of phosphoric acid, each time it was used in the
closets. If we consider each lb. of nitrogen with the phosphoric acid
worth 20 cents a lb., 5 tons of the dry earth, after being used once,
would be worth $1.46, or less than 30 cents a ton, and after it had been
used six times, five tons of the material would be worth $11.98, or
about $2.40 per ton.
In this calculation I have not reckoned in the value of the nitrogen the
soil contained before using. Soil, on a farm, is cheap.
It is clear from these facts that any earth-closet manure a farmer would
be likely to purchase in the city has not a very high value. It is
absurd to talk of making “guano” or any concentrated fertilizer out of
the material from earth-closets.
“It is rather a reflection on our science and practical skill,” said the
Doctor, “but it looks at present as though the only plan to adopt in
large cities is to use enormous quantities of water and wash the stuff
into the rivers and oceans for the use of aquatic plants and fishes. The
nitrogen is not all lost. Some of it comes back to us in rains and dews.
Of course, there are places where the sewage of our cities and villages
can be used for irrigating purposes. But when water is used as freely as
it ought to be used for health, the sewage is so extremely poor in
fertilizing matter, that it must be used in enormous quantities, to
furnish a dressing equal to an application of 20 tons of stable-manure
per acre.”
“If,” continued the Doctor, “the sewage is used merely as _water_ for
irrigating purposes, that is another question. The water itself may
often be of great benefit. This aspect of the question has not received
the attention it merits.”
PERUVIAN GUANO.
Guano is the manure of birds that live principally on fish.
Fish contain a high percentage of nitrogen and phosphoric acid, and
consequently when fish are digested and the carbon is burnt out of them,
the manure that is left contains a still higher percentage of nitrogen
and phosphoric acid than the fish from which it was derived.
Guano is digested fish. If the guano, or the manure from the birds
living on fish, has been preserved without loss, it would contain not
only a far higher percentage of nitrogen, but the nitrogen would be in a
much more available condition, and consequently be more valuable than
the fish from which the guano is made.
The difference in the value of guano is largely due to a difference in
the climate and locality in which it is deposited by the birds. In a
rainless and hot climate, where the bird-droppings would dry rapidly,
little or no putrefaction or fermentation would take place, and there
would be no loss of nitrogen from the formation and escape of ammonia.
In a damper climate, or where there was more or less rain, the
bird-droppings would putrefy, and the ammonia would be liable to
evaporate, or to be leached out by the rain.
Thirty years ago I saw a quantity of Peruvian guano that contained more
than 18 per cent of nitrogen. It was remarkably light colored. You know
that the white part of hen-droppings consists principally of uric acid,
which contains about 33 per cent of nitrogen.
For many years it was not difficult to find guano containing 13 per cent
of nitrogen, and genuine Peruvian guano was the cheapest and best source
of available nitrogen. But latterly, not only has the price been
advanced, but the quality of the guano has deteriorated. It has
contained less nitrogen and more phosphoric acid. See the Chapter on
“Value of Fertilizers,” Page 324.
SALTS OF AMMONIA AND NITRATE OF SODA.
“I wish,” said the Deacon, “you would tell us something about the
‘ammonia-salts’ and nitrate of soda so long used in Lawes and Gilbert’s
experiments. I have never seen any of them.”
“You could not invest a little money to better advantage than to send
for a few bags of sulphate of ammonia and nitrate of soda. You would
then see what they are, and would learn more by using them, than I can
tell you in a month. You use them just as you would common salt. As a
rule, the better plan is to sow them broadcast, and it is important to
distribute them evenly. In sowing common salt, if you drop a handful in
a place, it will kill the plants. And so it is with nitrate of soda or
sulphate of ammonia. Two or three pounds on a square rod will do good,
but if you put half of it on a square yard, it will burn up the crop,
and the other half will be applied in such a small quantity that you
will see but little effect, and will conclude that it is a humbug.
Judging from over thirty years’ experience, I am safe in saying that not
one man in ten can be trusted to sow these manures. They should be sown
with as much care as you sow grass or clover-seed.”
“The best plan,” said the Doctor, “is to mix them with sifted
coal-ashes, or with gypsum, or sifted earth.”
“Perhaps so,” said I, “though there is nothing gained by mixing earth or
ashes with them, except in securing a more even distribution. And if I
was going to sow them myself, I would much prefer sowing them unmixed.
Any man who can sow wheat or barley can sow sulphate of ammonia or
nitrate of soda.”
“Lawes and Gilbert,” said the Deacon, “used sulphate and muriate of
ammonia, and in one or two instances the carbonate of ammonia. Which is
the best?”
“The one that will furnish ammonia or nitrogen at the cheapest rate,”
said the Doctor, “is the best to use. The muriate of ammonia contains
the most ammonia, but the sulphate, in proportion to the ammonia, is
cheaper than the muriate, and far cheaper than the carbonate.”
Carbonate of ammonia contains 21½ per cent of ammonia.
Sulphate of ammonia contains 25¾ per cent of ammonia = 21⅕ of nitrogen.
Muriate of ammonia contains 31 per cent of ammonia = 25½ of nitrogen.
Nitrate of soda contains 16⅖ per cent of nitrogen.
Nitrate of potash, 13¾ per cent of nitrogen.
From these figures you can ascertain, when you know the price of each,
which is the cheapest source of nitrogen.
“True,” said I, “but it must be understood that these figures represent
the composition of a pure article. The commercial sulphate of ammonia,
and nitrate of soda, would usually contain 10 per cent of impurities.
Lawes and Gilbert, who have certainly had much experience, and doubtless
get the best commercial articles, state that a mixture of equal parts
sulphate and muriate of ammonia contains about 25 per cent of ammonia.
According to the figures given by the Doctor, the mixture would contain,
if pure, over 28 per cent of ammonia. In other words, 90 lbs. of the
pure article contains as much as 100 lbs. of the commercial article.”
As to whether it is better, when you can buy nitrogen at the same price
in nitrate of soda as you can in sulphate of ammonia, to use the one or
the other will depend on circumstances. The nitrogen exists as nitric
acid in the nitrate of soda, and as ammonia in the sulphate of ammonia.
But there are good reasons to believe that before ammonia is used by the
plants it is converted into nitric acid. If, therefore, we could apply
the nitrate just where it is wanted by the growing crop, and when there
is rain enough to thoroughly distribute it through the soil to the depth
of six or eight inches, there can be little doubt that the nitrate, in
proportion to the nitrogen, would have a quicker and better effect than
the sulphate of ammonia.
“There is another point to be considered,” said the Doctor. “Nitric acid
is much more easily washed out of the soil than ammonia. More or less of
the ammonia enters into chemical combination with portions of the soil,
and may be retained for months or years.”
When we use nitrate of soda, we run the risk of losing more or less of
it from leaching, while if we use ammonia, we lose, for the time being,
more or less of it from its becoming locked up in insoluble combinations
in the soil. For spring crops, such as barley or oats, or spring wheat,
or for a meadow or lawn, or for top-dressing winter-wheat in the spring,
the nitrate of soda, provided it is sown early enough, or at any time in
the spring, just previous to a heavy rain, is likely to produce a better
effect than the sulphate of ammonia. But for sowing in the autumn on
winter-wheat the ammonia is to be preferred.
“Saltpetre, or nitrate of potash,” said the Deacon, “does not contain as
much nitrogen as nitrate of soda.”
“And yet,” said the Doctor, “if it could be purchased at the same price,
it would be the cheaper manure. It contains 46½ per cent of potash, and
on soils, or for crops where potash is needed, we may sometimes be able
to purchase saltpetre to advantage.”
“If I could come across a lot of damaged saltpetre,” said I, “that could
be got for what it is worth as manure, I should like to try it on my
apple trees--one row with nitrate of soda, and one row with nitrate of
potash. When we apply manure to apple trees, the ammonia, phosphoric
acid, and potash, are largely retained in the first few inches of
surface soil, and the deeper roots get hold of only those portions which
leach through the upper layer of earth. Nitric acid, however, is easily
washed down into the subsoil, and would soon reach all the roots of the
trees.”