FARMYARD MANURE
Farmyard manure is the oldest, and is still undoubtedly the most
popular, of all manures. It has stood the test of long experience, and
has proved its position as one of the most important of all our
fertilisers. It is highly desirable, therefore, to make a somewhat
detailed examination of its composition, and to see on what the
variation in this depends; and, finally, to examine into the mode of its
action as a manure.
That it should prove a valuable manure is scarcely to be wondered at, as
it is originally formed from vegetable substance, and as it therefore
contains all the elements present in the plant itself.
Its composition is very variable, and probably no two samples would
yield exactly similar analyses. In this fact lies one of the chief
difficulties of the treatment of the subject, and all statements made
in the following pages as to its chemical composition must be taken as
only _approximate_.
We may divide its constituents into three classes.
1. That portion due to _solid excreta_.
2. The liquid portion, largely made up of dilute _urine_.
3. The _straw_, or other material, which is used as litter.
The composition of the manure will vary according to the proportion in
which these three substances are present, as well as according to the
composition of the substances themselves. It will consequently tend to a
clearer apprehension of the subject if we first examine briefly the
chemical composition of the solid excreta and urine of the farm animals.
1. _Solid Excreta._
The manurial value of the solid excreta of animals--_i.e._, the
proportion they contain of _nitrogen_, _phosphoric acid_, and
_potash_--depends on a variety of conditions.
The solid excreta of horses, sheep, cows, and pigs, are well known to
possess different properties, as well as to vary in their composition.
What, however, has a still greater influence is the nature of the food.
This is owing to the fact that the solid excreta are made up of
undigested food. We can scarcely expect the same quality of solid
excreta from an animal fed on poor diet as from an animal fed on very
much richer diet. Again, the percentage of the food voided in the solid
excreta varies in the case of different animals.[131]
Another consideration which enters into the question is the age, as well
as the treatment, of the animal. A young animal, during the period of
its growth, absorbs from its food into its system a larger quantity of
the three fertilising substances, nitrogen, phosphoric acid, and potash,
than is the case with an adult animal whose weight is neither increasing
nor diminishing. A working horse, similarly, will return more of the
nitrogen, phosphates, and potash in its dung than one not at work and
which is permitted to gain in weight. The nature of the composition of
the solid excreta, therefore, will depend on the nature of the _food_,
_age_, _breed_, _condition_, and _treatment_ of the animal.
Let us now investigate shortly the influence of the above
considerations. The solid excrements of the common farm animals are
generally distinguished from one another according to the rate at which
they decompose or ferment on keeping. Thus horse-dung is generally known
as a "hot" dung; while cow-dung, on the other hand, is known as "cool."
Why this should be so is not absolutely clear. Probably it is owing to
the fact that the former contains less water, as well as to the fact
(and this probably has more to do with it) that it contains a larger
percentage of fertilising matter, especially nitrogen, thus affording
conditions more favourable for rapid fermentation than in the case of
the more moist and less rich cow-dung.
The composition of the solid excreta of various animals, as we have just
said, varies with the nature of their food; so that it is impossible to
take any analyses as absolutely representing its composition. It may be
interesting, however, to compare the analyses of samples of horse-dung
with those of some other of the commoner farm animals, with a view to
obtaining an _approximate_ idea of this difference.
Stoeckhardt has found that in 1000 lb. of the fresh solid excreta of the
animals below mentioned, there were the following amounts of _nitrogen_,
_phosphoric acid_, and _alkalies_:--
-----------------------+----------+-------------+-------------+-----------
| | | PHOSPHORIC |
| | NITROGEN. | ACID. | ALKALIES.
| WATER. |-----+-------+-----+-------+---+-------
| | |Reduced| |Reduced| |Reduced
| | | to | | to | | to
-----------------------+----+-----+-----+-------+-----+-------+---+-------
|lb. | per | lb. | per | lb. | per |lb.| per
| |cent.| | cent. | | cent. | | cent.
Horses (winter food) |760 |76 |5 | .50 |3-1/2| .35 | 3 | .30
Cows (winter food) |840 |84 |3 | .30 |2-1/2| .25 | 1 | .10
Swine (winter food) |800 |80 |6 | .60 |4-1/2| .45 | 5 | .50
Sheep (2 lb. hay per | | | | | | | |
diem) |580 |58 |7-1/2| .75 |6 | .6 | 3 | .30
-----------------------+----+-----+-----+-------+-----+-------+---+-------
From the above table it will be seen that the sheep's dung contains the
least percentage of _water_, and is richer in _nitrogen_ and _phosphoric
acid_ than any of the other three. The percentage of alkalies, of which
the most important is potash, is, however, not so large. This may be
accounted for by the interesting and well-known fact that a large
percentage of potash is to be found in the wool of sheep.[132]
The solid excrement of the sheep is, therefore, weight for weight, the
most valuable as a manure, as it contains more nitrogen and phosphates
than the others, and at the same time is much drier.
If, however, we compare the composition of the solid excreta in a dry
state, we shall find that the following are the results (basing our
calculation on Stoeckhardt's analyses):--
Nitrogen, Phosphoric acid, Alkalies,
per cent. per cent. per cent.
Horse 2.08 1.45 1.25
Cow 1.87 1.56 0.62
Pig 3.00 2.25 2.50
Sheep 1.78 1.42 0.71
It will be seen from the above that the dry substance of the solid
excreta of the pig is richest in fertilising substances. Too much
stress, however, as has already been pointed out, must not be put on any
single analysis, as so much depends on various conditions, especially
the food.[133] The most reliable method of studying this question,
therefore, is to study it in its relation to the food consumed. Wolff
has calculated from numerous investigations that, with regard to the
amount of solid excreta produced by the food, the following percentage
of _organic matter_, _nitrogen_, and _mineral substances_, originally
present in the dry matter of the food, is voided in the dung:--
Cow. Ox. Sheep. Horse. Average.
Organic matter 39.5 42.5 44.0 44.1 42.5
Nitrogen 47.5 33.9 46.7 32.4 40.1
Mineral substances 53.9 64.6 57.9 62.5 59.7
There is one fact to be borne in mind in estimating the manurial value
of the dung of different animals--viz., that the quantity of dung voided
by one animal is much greater than that voided by another. Thus the
amount voided by the cow, for example, is much greater than that voided
by the horse; so that, in this way, the inferior quality of the former
is, to some extent, compensated for by its greater quantity.
2. _Urine._
The solid excreta possess, however, very much less manurial value than
the urine. The former, as already stated, are undigested
food-substances: any fertilising matters which they contain are such as
have failed to be digested or absorbed into the animal system. The
urine, on the other hand, contains those fertilising substances which
have been digested.
The amount of nitrogen and mineral matter, however, in the urine, does
not represent necessarily the total amount of these substances. Thus, in
the case of a growing or fattening animal, there is always a certain
amount of these substances being absorbed to build up the animal tissue
and put on flesh.
In this respect it will be seen that the composition of urine will vary
in the same way as that of the dung. In the case of the urine, however,
there is a compensating influence to be taken into account. Urine is a
waste product, and there is more waste in a young than in an adult
animal.
Another very important condition which determines the composition of
urine is the nature of the food, especially the quantity of water drunk.
This, of course, is obvious: the more water drunk, the poorer must the
composition of the urine be. But here again, as in the case of the dung,
this is largely compensated for by the total quantity voided--the more
dilute the urine, the larger will its quantity be; so that the inferior
quality is in this way made up for by its increased quantity.
Keeping in mind, then, the fact we have just stated--viz., that the
composition of urine will vary according to different conditions--we may
obtain an approximate idea of what its composition is from the following
results of analyses by Stoeckhardt. In 1000 parts the following
quantities of _water_, _nitrogen_, _phosphoric acid_, and _alkalies_
were found to be present.
From the following table it will be seen that the urine of swine
(containing 97 per cent of water) is much poorer in nitrogen and
alkalies than is the case with the urine of the sheep, horse, or
cow.[134] While this is the case, the amount of phosphoric acid it
contains is greater than that contained in the sheep's urine.
-------------------+------------+-------------------------+------------
| | | Phosphoric |
| Water. | Nitrogen. | Acid. | Alkalies.
+------+-----+------+-----+------+-----+------+-----
| Per | Per | Per | Per | Per | Per | Per | Per
| 1000 |cent.| 1000 |cent.| 1000 |cent.| 1000 |cent.
|parts.| |parts.| |parts.| |parts.|
-------------------+------+-----+------+-----+------+-----+------+-----
Sheep (2 lb. hay }| 865 | 86.5| 14 | 1.4 | .5 | .050| 20 | 2.0
per diem) }| | | | | | | |
| | | | | | | |
Swine (winter food)| 975 | 97.5| 3 | .3 | 1.25 | .125| 2 | .2
| | | | | | | |
Horses (hay and }| 890 | 89.0| 12 | 1.2 | - | - | 15 | 1.5
oats) }| | | | | | | |
| | | | | | | |
Cows (hay and }| 920 | 92.0| 8 | .8 | - | - | 14 | 1.4
potatoes) }| | | | | | | |
-------------------+------+-----+------+-----+------+-----+------+-----
Phosphoric acid is present in the urine of the farm animals in the most
minute traces: practically, it may be considered to be wanting in the
urine of the horse and the cow, and is present only in small quantities
in sheep's urine. The pig's urine, indeed, contains it in larger
quantities; but the percentage is still so small as to justify the
statement that the urine of the common farm animals is not a complete
manure, and must be supplemented by phosphates, if it is to be used
alone. The incomplete nature of urine as a manure constitutes a strong
argument in favour of its being applied along with the solid excreta,
which contain, as we have seen, considerable quantities of phosphoric
acid. It is on this account that the drainings of rotten manure-heaps
are more valuable, from a manurial point of view, than urine itself,
since these contain the soluble portion of the phosphates in the solid
excreta.[135] The urine of all animals, however, is not equally poor in
phosphates. In the case of flesh-eating animals, such as the dog, the
urine is found to contain them in considerable quantities.
The above tables show that the most valuable urine, weight for weight,
is that of the sheep, as it contains the largest amount of alkalies
(including potash) and nitrogen; that the urine of the horse comes next;
then that of the cow; while, as has already been pointed out, that of
the pig is the poorest.
In order to make our survey of the composition of urine uniform with
that of the dung, let us see how the urine of the common farm animals
compares in the matter of the composition of its dry substance. The
following results (basing our calculations on Stoeckhardt's figures,
previously given) show this:--
Nitrogen, Phosphoric acid, Alkalies,
per cent. per cent. per cent.
Pig 12.0 5 8
Horse 10.9 trace 13.6
Sheep 10.4 3.7 14.9
Cow 10.0 trace 17.5
From these figures we see that the dry substance of the urine of the pig
is richest in nitrogen and phosphoric acid, but poorest in alkalies, of
the four common farm animals; that of the horse comes next in the amount
of nitrogen it contains, but that, on the whole, there is very little
difference between the horse, cow, and sheep in this respect.[136]
As in the case of the dung, this subject is best studied in relation to
the food consumed. We are again indebted to Wolff's investigations for
valuable information on this point. He has found that the following
percentages of _organic matter_, _nitrogen_, and _mineral substances_,
originally present in the dry matter of the food, are voided in the
urine:--
Cow. Ox. Sheep. Horse. Average
Organic matter 4.0 4.4 2.0 3.3 3.4
Nitrogen 31.0 54.8 42.3 60.7 47.2
Mineral substances 43.1 34.3 41.0 37.5 39.0[137]
We have now considered briefly the composition of the solid excrements
and urine of the common farm animals, and have also enumerated some of
the principal causes of the variation in their composition.
The solid excreta consist, as we have seen, of _undigested_ food, while
the urine contains the manurial ingredients of the food which have been
_digested_ by the animal system.[138] The latter is, weight for weight,
as a rule, very much more valuable as a manure than the former. From
the table given in the Appendix[139] it will be seen that the
proportions of the nitrogen and ash-constituents originally present in
the food consumed, which are voided in the excrements, vary with
different circumstances. Wolff, in summarising his results, points out
that, as a rule, the solid and liquid excrements will contain about 46
per cent of the organic matter, 87.3 of the nitrogen, and 98.7 of
mineral matter; while the experiments of Lawes and Gilbert at Rothamsted
show that, with fattening oxen and sheep and with horses, more than 95
per cent of the nitrogen and 96 per cent or more of the ash-constituents
are voided in the manure. The pig retains a larger proportion of the
nitrogen--about 85 per cent appearing in the manure--while in the
milking-cow only about 75 per cent is returned in the excrements.
Generally speaking, we may say that the nitrogen originally present in
the food suffers very little loss in passing through the animal system,
and that, practically speaking, the ash-constituents suffer no loss
whatever.
As to the distribution of the manurial ingredients, much will depend on
the nature of the food. Almost invariably more than a _half_ of the
total nitrogen excreted will be found in the urine, in many cases very
much more.[140] Of the mineral constituents, about a third on the
average may be said to be excreted in the urine. Of this mineral matter
it may be noted that nearly all the alkalies (potash and soda), or about
98 per cent, are found in the urine. Of phosphoric acid and lime, on the
other hand, there are the merest traces in the urine. Horse-urine,
however, is an exception with regard to lime, as it contains about 60
per cent of the lime consumed in the food. For information on the
subject of pig-manure the reader is referred to Appendix, Note V.[141]
Before passing from this part of the subject, it may be desirable to
place before our readers the composition of the dung and urine taken
together, so that we may be able to form some idea of their relative
value, weight for weight. As the nitrogen constitutes by far the most
valuable portion of the manurial ingredients, it will be sufficient if
we compare them as to their percentage of this ingredient.
Water, Nitrogen, Calculated on
per cent. per cent. dry substance, Analyses by
per cent.
Sheep 67 .91 2.7 Juergensen.
Horse 76 .65 2.7 Boussingault.
Pig 82 .61 3.4 Boussingault.
Cow 86 .36 2.6 Boussingault.
From these figures we see that, in their natural condition, the excreta
of the sheep are the most valuable; those of the horse and pig coming
next; while those of the cow are the poorest, containing one-third as
much nitrogen as those of the sheep, and one-half as much as those of
the horse and pig. This difference, however, is due almost entirely to
the different percentage of water the excreta of the various animals
contain in their natural state; for in the dry state they are seen to
contain, with the single exception of the pig, practically the same
amount.
In conclusion, then, the important points to be noticed are--
1. That in the passage of the food through the system of the common farm
animals, only a very small percentage of the fertilising substances,
nitrogen, phosphoric acid, and potash, is assimilated and retained in
the animal body; and that, therefore, theoretically at least, the
excreta should contain nearly the same amount of fertilising matter as
the food originally did.
2. That even in the case of a fattening animal, the loss of fertilising
matter sustained by the food in passing through the system is not great.
3. That with regard to the total amount of solid excreta and urine
voided, the latter contains, as a rule, more nitrogen than the former;
the nitrogen in the urine, further, being more valuable, as it is in a
soluble condition.
4. That as regards the distribution of the ash-constituents, _lime_,
_phosphoric acid_, and _magnesia_ are almost entirely found in the solid
excrements; while the urine contains nearly all the _potash_.
5. That the best results can be expected only when the liquid and solid
excreta are used together as a manure.
As the composition of the manure depends so largely on the nature of the
food, a table will be found in the Appendix, Note VI.,[142] containing
the manurial composition of some of the commoner feeding-stuffs.
3. _Litter._
We have now to consider the third constituent of farmyard manure--viz.,
the _litter_, which generally consists of straw.
The uses of the litter, in addition to providing a dry and comfortable
bed for the animal, may be briefly summed up as follows:--
1. To absorb and retain the liquid portion of the excreta.
2. To increase the quantity of the manure, and thus secure its more
equal distribution when applied to the field than could otherwise be
done.
3. To add to its value as a manure, both physically and chemically.
4. To retard and regulate the decomposition of the excreta.
Of course litter also performs a very useful function sanitarily,
inasmuch as it serves to keep the stall or byre fresher and cleaner, and
more free from noxious gases, which it absorbs, than would otherwise be
the case.
_Straw_ is almost universally used for this purpose. Besides being one
of the bye-products of the farm, it is admirably suited in many ways,
both owing to its peculiar shape--its tubular structure being
excellently adapted for this purpose--as well as on account of its
composition, being largely composed of cellulose, a very absorptive
substance. Straw thus possesses considerable absorptive power. In
manurial ingredients it is not very rich; for, of the various parts of
the ripened plant, straw contains the least percentage of nitrogen and
phosphates. This is due to the fact that, as the straw ripens, a
considerable proportion of these ingredients passes up from the stalk to
the seeds, where they are retained.
Generally speaking, straw may be said to contain not more than _a half
per cent_ of nitrogen--_i.e._, 11.2 lb. per ton. Its percentage of
nitrogen varies, of course; the recorded analyses[143] for wheat-straw
ranging from .22 to .81 per cent, or furnishing an average of .48 per
cent--_i.e._, 10.75 lb. per ton. Barley-straw is somewhat richer in
nitrogen, the recorded analyses ranging from .41 to .85 per cent, or
giving an average of .57 per cent--_i.e._, 12.76 lb. per ton; while
oat-straw is the richest of the commoner straws, ranging from .32 to
1.12 per cent, an average of .72 per cent--_i.e._, 16.12 lb per ton.
Of mineral matter, however, straw contains a very much larger
percentage, proportionally, than of nitrogen; for, with the exception of
phosphates, there is a considerable quantity of inorganic fertilising
matter, in the shape of potash, lime, &c., present in
Composition of Straw.[144]
-----------------+---------------+------------------------+--------
| Ash. | Composition of Ash. |
+------+--------+------------------------+
| | | Lb. per ton. |
| | Lb. |-------+----------+-----| Number
| Per | per |Potash.|Phosphoric|Lime.| of
| cent.| ton. | | Acid | |Analyses
-----------------+------+--------+-------+----------+-----+--------
Wheat (winter) | 5.54 | 124.09 | 18.61 | 5.05 | 7.18| 8
Wheat (summer) | 5.14 | 115.13 | 25.76 | 6.47 | 7.12| 6
Rye (winter) | 5.33 | 119.39 | 20.61 | 5.89 | 9.73| 8
Rye (summer) | 6.14 | 137.53 | 42.41 | 6.73 |10.53| 1
Barley | 4.90 | 109.76 | 26.83 | 5.75 | 8.73| 8
Oats | 5.09 | 114.01 | 26.22 | 4.17 | 9.12| 4
-----------------+------+--------+-------+----------+-----+--------
it. Of total ash ingredients, on an average, there are generally about 5
per cent--or 112 lb. per ton. The largest percentage of the fertilising
matter in this 5 per cent is potash, which varies in the ashes of the
straws of the commoner crops from 30 to 15 per cent. The above table
will show the variation in composition of the straws of some of the
commoner farm crops, and may be valuable for purposes of reference. The
crops are wheat (winter and summer), barley, oats, and rye (winter and
summer), and the amount is also calculated in lb. per ton. The results
represent the average of a number of analyses.[145] From the table it
will be seen that the percentage of phosphates is, as has already been
noticed, very small.
But while straw is well adapted for the purposes for which litter is
used, it is not the only substance. Its almost exclusive use as litter
is largely owing to the fact that it is a bye-product of the farm.
_Loam as Litter._--Generally speaking, any substance which has great
absorptive as well as retentive powers for nitrogen and the soluble
fertilising matters present in farmyard manure, and whose price is
nominal, is well suited for acting as litter. Ordinary loamy soil
possesses the above qualifications, and is, besides, a substance to be
had for nothing, and, under certain circumstances and in certain
countries, is actually used for this purpose, often along with straw. A
great objection against loam, however, is that it forms a dirty litter.
Moreover, it possesses a very small percentage of fertilising matter.
The tendency, consequently, in using ordinary loam, would be to dilute
the manure too much, besides retarding fermentation to an undesirable
extent. Except, therefore, under very exceptional circumstances, loam is
not to be regarded as a good litter.
_Peat as Litter._--Some kinds of soil, however, are well suited for this
purpose. Of these, the best are those rich in organic matter, the
so-called peaty soils. Peat, when dried and freed from any earthy
matter, forms an excellent absorbent of the liquid portion of the
manure, surpassing in this respect straw itself. It is, further,
generally very much richer in nitrogen--some peats having been found to
contain between 4 and 5 per cent of nitrogen. In some thirty samples of
peat analysed by Professor S. W. Johnson, the percentage of nitrogen
varied from .4 to 2.9, giving an average of 1.5 per cent.
While it has a very great capacity for absorbing liquids, it possesses
in an unequalled degree the power of retaining the soluble nitrogen
compounds. This is undoubtedly one of the most important properties
which recommend peat for the purposes of litter.[146]
Some interesting experiments on the value of peat-moss as a litter have
been recently carried out by Dr Bernard Dyer.[147] From these
experiments Mr Dyer has found that both its liquid-absorbing and
liquid-retaining powers are very much greater than those of straw. While
straw was only able to absorb three times its weight of water, peat-moss
was found to absorb nearly ten times its weight. With regard to its
water-retaining power, this was also found to be in excess of that of
straw. Both these properties are, it need scarcely be pointed out, of
very great value in a litter. Another point of interest in these
experiments was the respective amounts of nitrogen absorbed and retained
by the peat-moss and the straw. It was found that, in this respect, the
peat-moss had again an advantage over the straw. Lastly, the manure
produced by the peat-moss was shown to be richer in fertilising matter
than that produced by the use of straw.[148] These experiments are
interesting as demonstrating the fact that in peat-moss we have a
substance which is capable of acting as an excellent substitute for the
more costly straw, and which might increasingly be used as a fodder with
great benefit to the farmer.
Another substance which has been suggested as an excellent litter is the
common _bracken-fern_. According to some analyses made by Mr John
Hughes, the bracken, especially if cut in a young state, is a substance
of considerable manurial value. When dried, it is very much richer in
nitrogen, potash, and lime than straw. Its absorbent properties,
however, are probably not so great. Where it can easily and cheaply be
had, as in many parts of Scotland and Ireland, it might well be used for
littering purposes.[149]
_Dried leaves_ have also been used as a litter. Autumn leaves, however,
contain a very small percentage of fertilising matter. This is due to
the fact that the most of their potash, phosphoric acid, and nitrogen
pass into the body of the trees at the approach of winter. According to
Professor Storer, dried leaves only contain from .1 to .5 per cent
potash,.006 to .3 per cent phosphoric acid, and about .75 per cent of
nitrogen. Leaves, however, besides being poor in manurial ingredients,
make a bad litter, as they ferment but slowly. There is in this
fermentation a large quantity of cold sour humic acid formed, which
seriously impairs the value of the manure.[150]
Having now considered the composition of the three separate ingredients
of farmyard manure--viz., the _dung_ or _solid excreta_, the _urine_,
and the _litter_--we are in a position to consider the composition of
farmyard manure. In this connection it will be well to consider
separately the manures produced by the different farm animals.
1. _Horse-manure._
The composition of horse-manure is perhaps the most uniform of all the
manures produced by the different farm animals. This is due to the fact
that the food of the horse is generally of the same kind, consisting of
oats, hay, and straw.
The total excrements voided by a horse in a day have been calculated,
according to the average of experiments by Boussingault and Hofmeister,
at 28.11 lb., of which only 6.37 lb. consisted of dry matter.[151] These
28.11 lb. contained .18 lb. of nitrogen and .92 lb. of mineral matter.
The amount of straw necessary to absorb this amount of excrement may be
stated at from 4 to 6 lb. The amounts of nitrogen and mineral matter in
4 lb. of straw are .01 and .23 lb. respectively. The total amount of
nitrogen and ash, therefore, in the farmyard manure produced by a horse
in one day, would be .19 lb. nitrogen and 1.15 lb. mineral matter; or,
if we take the larger quantity of straw, somewhat more.
Taking these figures, we find that the amount of manure produced by a
horse in a year will be from 11,720 to 12,450 lb. (_i.e._, from 5-1/4
to 5-1/2 tons),[152] containing from 69 to 73 lb. nitrogen, and from 420
to 460 lb. mineral matter.[153]
A word or two may be of value regarding the treatment in the stable of
horse-manure. The great object to be aimed at is the prevention of loss
of valuable fertilising constituents. This loss may be due to two
causes. It may be, in the first place, caused by drainage of the soluble
matter of the manure; or secondly, it may be due to volatilisation of
the volatile constituents.
The first of these two sources of loss depends on the precautions taken
in the way of providing a proper impervious flooring to the stable. This
source of loss is extremely difficult to prevent, inasmuch as nearly all
materials used for flooring absorb a certain percentage of urine. The
judicious use of litter, however, will minimise this loss to within a
trifling extent.
Dr Heiden states that the amount of straw used as litter for the horse
in Germany is from 4 to 6 lb. per day. The quantity should be regulated
according to the percentage of water the excreta contain; the more
watery excreta requiring naturally a larger quantity of litter. The most
eminent authorities on this subject recommend that the amount of litter
should equal one-fourth of the food in its natural state, or about
one-third of its dry substance.
The second source of loss, which is due to volatilisation of the
volatile ingredients, may be largely prevented by the use of certain
preservatives.
Horse-dung being, comparatively speaking, of a dry nature, it is
extremely difficult to effect its thorough mixture with the litter. For
this reason the manure formed from horse excreta is particularly liable
to rapid fermentation.[154] In the process of fermentation, as will be
seen more in detail further on, the nitrogen is converted into carbonate
of ammonia. As nitrogen in this form is of an extremely volatile nature,
the risks of loss from this source are considerable. As illustrating
this fact, it may be mentioned that Boussingault has found by experiment
that the total percentage of nitrogen contained by fresh horse-manure
might be reduced in the process of fermentation to one-half of its
original amount by loss from this source.
The preservatives used to prevent this volatilisation are technically
known as "fixers." This they do by chemically combining with the
volatile ammonia and forming non-volatile compounds with it.
Of the acid fixers, hydrochloric and sulphuric acids have been
recommended. The former, however, is not well suited for this purpose.
It is a strongly fuming acid, and when brought into contact with
ammonia forms dense white fumes. The use of sulphuric acid is not open
to this objection. Sulphate of ammonia, the salt formed in this case, is
one of the most stable (or least volatile) of the compounds of ammonia.
If used, it should be largely diluted with water, and the whole mixed
with sand. Such a mixture, when sprinkled over the stable-floor in even
very small quantities, has been found to effectually prevent any loss of
the volatile carbonate of ammonia.
It is not, however, on the whole advisable to use an acid substance as a
fixer, since such a substance may act deleteriously on the horses'
hoofs.
Such substances as _gypsum_, _copperas_, and _sulphate of magnesia_,
while equally efficient, are not open to this objection. The
above-mentioned substances owe their efficacy to the fact that they are
compounds of sulphuric acid, which, by combining with the volatile
ammonia and forming sulphate of ammonia, prevent its escape.
Gypsum, or sulphate of lime, although, comparatively speaking, an
insoluble substance, when brought in contact with carbonate of ammonia
has been proved to effect the conversion of the ammonia into sulphate of
ammonia. It is also believed to retard the decomposition of the
manure.[155] Copperas, or ferrous sulphate, while a soluble salt, and
while thus acting in a more speedy manner in fixing the ammonia, is not
so well suited, owing to the hurtful influence it is well known to
possess on plant-life. It is only right to remember that there may be
circumstances in which copperas may, in small quantities, act even
beneficially as a manure, as Griffiths' experiments would seem to
indicate. The above objection, however, cannot be urged against sulphate
of magnesia. In addition to fixing the ammonia, sulphate of magnesia may
very probably fix the soluble phosphoric acid. Kainit, which consists of
a mixture of sulphates and chlorides of potassium and magnesium, has
also been suggested for this purpose. By using such a fixer, the value
of the resulting manure would be much enhanced. In conclusion, it must
be remembered that all the above-named fixers act very much in the same
way--viz., by converting the volatile carbonate of ammonia into sulphate
of ammonia.[156]
2. _Cow-manure._
The composition of the manure formed from the excrementitious matter of
the cow is very much less constant than is the case in the horse-manure.
An average statement of that composition is therefore very much more
difficult to obtain. The number of analyses available for the purpose of
forming this average is, however, very large. The manure produced by
cows contains a large percentage of water. This is due to the large
quantity of water they drink. It has been estimated that milch-cows
drink along with their winter food, for every pound of dry substance, 4
lb. of water, and in summer about 6 lb.
According to some experiments by Boussingault, the excrements of a cow
in a day amounted to 73.23 lb., of which only 9.92 lb. were dry
matter.[157] These excrements contained .256 lb. of nitrogen and 1.725
lb. of mineral matter. The amount of straw necessary to use as litter
for this amount of excrements may be taken at 6 to 10 lb. The manure,
therefore, formed by a cow per day, would contain from .274 to .286 lb.
of nitrogen, and from 2.046 to 2.278 lb. of mineral matter. In a year
this would amount to from 100 to 104.4 lb. of nitrogen, and from 746.8
lb. to 831.5 lb. of mineral matter; or from 6 cwt. 75 lb. to 7 cwt. 47
lb.
Cow-dung is, owing to its more watery nature and poorer quality, very
much slower in its fermentation than horse-dung. When applied alone,
cow-manure is very slow in its action, and makes its influence felt for
at least three or four years. It is difficult to spread it evenly over
the soil, owing to the fact that, when somewhat dried, it has a tendency
to form hard masses, which, when buried in the soil, may resist
decomposition for a very long period. The cause of this is due to the
presence of a considerable amount of mucilaginous and resinous matter in
the solid excreta, which prevents the entrance of moisture and air into
the centre of the mass. This tendency of cow-manure to resist
decomposition will be greatly lessened in the case of the excrements of
a cow richly fed.
The risks of loss of volatile ammonia are, therefore, in its case not so
great as we have seen them to be in the case of the "hot" horse-dung.
Notwithstanding this fact, much of what has been said on the use of
preservatives for horse-manure may be also applied to the cow-dung. This
is owing to the fact that the dung is allowed to accumulate in the court
for some time. The amount of straw it is advisable to use as litter
varies, as has been said, from 6 to 10 lb. per day. The best method of
calculating this amount, according to Dr Heiden, is by taking one-third
of the total weight of the dry substance of the food. The above
authority also recommends that the straw is best applied in blocks of
about one foot in length; and this for the following reasons:--
1. The strewing of it is more convenient.
2. The absorption of the fluid portion is more complete.
3. The cleaning out of the manure from the byre is easier.
4. The manure is more easily distributed when applied to the field.
Among the advantages incidental to allowing the manure to accumulate in
the court may be mentioned the following:--
1. The more thorough absorption of the urine by the straw, and,
consequently, the more uniform mixture which will be thus effected of
the more valuable urine with the less valuable solid excreta.
2. A certain retardation of decomposition effected by the treading under
foot of the manure.
3. The protection of the manure from rain and wind, and the securing of
a uniform temperature.
Against those advantages must be placed the risk of seriously affecting
the health of the animal. Although this is a point of very great
importance, it scarcely falls within the scope of this work. It may be
pointed out, however, that the judicious use of some of the chemical
fixers previously referred to may do much to keep the air of the byre or
court free of noxious gases.[158]
3. _Pig-manure._
The food of the pig is so very variable in its character that it is
wellnigh impossible to obtain anything like an average analysis of its
excrements. When the food of the pig is rich, then the manure may be
quite equal in quality to the other manures. According to Boussingault,
the total amount of excrements, on an average, voided by a pig in
twenty-four hours is about 8.32 lb., of which 1.5 lb. is dry
matter.[159] The amount of nitrogen these excrements contain is only .05
lb., and of mineral ingredients .313 lb. If we take the amount of straw
most suitable for absorbing this quantity of excrementitious matter at
from 4 to 8 lb., then we shall find that the manure produced by a pig
will contain from .06 to .074 lb. nitrogen and .545 to .772 lb. mineral
matter. These quantities, calculated for a year, give from 22 to 27 lb.
of nitrogen, and from 1 cwt. 87 lb. to 2 cwt. 57 lb. of mineral matter.
That is about as much nitrogen as would be contained in 1-1/4 to 1-1/2
cwt. of nitrate of soda (95 per cent purity); or from slightly less than
1 cwt. to slightly over 1 cwt. of sulphate of ammonia (97 per cent
purity).
As has already been pointed out, the excrements of the pig are, as a
rule, very poor in nitrogen. This accounts for the fact that pig-manure
is a "cold" manure, slow in fermenting.[160]
4. _Sheep-manure._
The dung and the urine of the sheep, as we have already seen, are,
weight for weight, the most valuable of any of the common farm animals.
The total weight of the excrements voided by a sheep in a day may be
taken, on an average,[161] at 3.78 lb., of which .97 lb. is dry matter.
These excrements contain .038 lb. of nitrogen and .223 lb. mineral
matter. Taking the amount of straw most suitable for absorbing this
quantity of excrementitious matter at three-fifths of a pound, then the
manure produced by a sheep in a day will contain .0429 lb. nitrogen and
.264 lb. mineral matter. That is, in a year the quantities of nitrogen
and mineral matter in the manure produced by a sheep would be 15.66 lb.
of nitrogen and 96.36 lb. of mineral matter.
From its richness in nitrogen, and from its dry condition, sheep-dung is
peculiarly liable to ferment. While richer in fertilising substances
than horse-manure, it is not so rapid in its fermentation. This is due
to the harder and more compact physical character of the solid excreta.
The risks of loss of volatile ammonia are, in its case, exceptionally
great. The use of artificial "fixers" is therefore to be strongly
recommended.[162]
_Fermentation of Farmyard Manure._
Having now considered the nature of the different manures produced by
the four common farm animals separately, it is of importance to consider
the exact nature of the fermentation, decomposition, or putrefaction
which takes place in the manure-heap.
It is now more than thirty years since Pasteur showed that the
fermentation which ensued on keeping a sample of urine was due to the
action of a minute organism, for the propagation of which a certain
amount of warmth, air, and moisture, as well as the presence of certain
food-constituents, especially nitrogenous bodies, were necessary.
Subsequent researches by Pasteur and others have conclusively
demonstrated that the micro-organic life instrumental in effecting the
putrefaction or decay of organic matter of any kind, may be divided into
two great classes:--
1. Those which require a plentiful supply of oxygen for their
development, and which, when bereft of oxygen, die--known as _aerobies_.
2. Those which, on the contrary, develop in the complete absence of
oxygen, and which, when exposed to oxygen, die--known as _anaerobies_.
In the fermentation of the manure-heap, therefore, we must conceive of
the two classes of organisms as the active agents. In the interior
portion of the manure-heap, where the supply of oxygen is necessarily
limited, the fermentation going on there is effected by means of the
anaerobic organism--_i.e._, the organism which does not require oxygen;
while on the surface portion, which is exposed to the air, the aerobic
(or oxygen-requiring) organism is similarly active. Gradually, as decay
progresses, the aerobic organisms increase in number. It is through
their instrumentality that the final products of decomposition are
largely produced. The functions of the anaerobic organisms may be, on
the contrary, regarded as largely preparatory in their nature. By
breaking up the complex organic substances in the manure into new and
simpler forms, they advance the process of putrefaction through the
initial stages; and when this is accomplished, they die and give place
to the aerobic, which, as we have just seen, effect the final
transformation of the organic matter into such simple substances as
_water_ and _carbonic acid gas_.
The conditions influencing the fermentation of farmyard manure may be
summed up as follows:[163]--
1. _Temperature._--The higher the temperature the more rapidly will the
manure decay.
2. _Openness to the Air._--Of course it will be seen that the effect of
exposing the manure to the action of the air is to induce the
development of the aerobic type of organism, and thus to promote more
rapid fermentation. If, on the other hand, the manure be impacted, the
slower but more regular fermentation, due to the anaerobic type of
organism, will be chiefly promoted. It must be remembered that in the
proper rotting of farmyard manure both kinds of fermentation should be
fostered. It is, in fact, on the careful regulation of the two classes
of fermentation that the successful rotting of the manure depends. It
must further be remembered that, even with a certain amount of openness
in a manure-heap, anaerobic fermentation may take place. This is due to
the fact that the evolution of carbonic acid gas, in such a case, is so
great as to exclude the access of the atmospheric oxygen into the pores
of the heap.
3. The _dampness_ of the manure-heap is another important influence.
This, of course, will act in two ways. First, by lowering the
temperature. Where the manure-heap is found to be suffering from
"fire-fang," the common method in practice is to lower the temperature
by moistening the heap with water. Secondly, it acts as a retarder of
fermentation by limiting the supply of atmospheric oxygen, and thus
preventing, as we have just seen, aerobic fermentation.
4. The fourth chief influence in regulating fermentation of the
manure-heap is its _composition_, and more especially the amount of
nitrogen it contains in a soluble form. The rate at which fermentation
takes place in any organic substance may be said chiefly to depend on
the percentage of soluble nitrogenous matter it contains: the greater
this is in amount, the more quickly does fermentation go on. There are
always a number of soluble nitrogenous bodies in farmyard manure. These
are chiefly found in the urine, such as _urea_, _uric_ and _hippuric
acids_, and _ammonia_ salts.
_Products of Decomposition of Farmyard Manure._
The most important of the changes which take place in the rotting of
farmyard manure may be briefly enumerated as follows:--
1. The gradual conversion into gases of a large portion of the organic
elements in the manure. Of these gaseous products the most abundant is
_carbonic acid gas_ (CO_2). It is in this form that the carbonaceous
matter which constitutes the chief portion of the manure escapes into
the air. Carbon also escapes into the air, combined with hydrogen, in
the form of _carburetted hydrogen_ or _marsh-gas_ (CH_4), a product of
the decomposition of organic matter in the presence of a large quantity
of water. This gas is consequently found bubbling up through stagnant
water. Next to carbonic acid gas, _water_ (H_2O) is the most abundant
gaseous product of decomposition. The nitrogen present in the manure, in
different forms, is converted by the process of decomposition chiefly
into _ammonia_, which, combining with the carbonic acid, forms carbonate
of ammonia, a very volatile salt. It is to this fact that one of the
great sources of loss in the decomposition of farmyard manure is due. If
the temperature of the manure-heap be permitted to rise too high, the
carbonate of ammonia volatilises. It is probable, also, that a not
inconsiderable portion of the nitrogen escapes into the air in the free
state. The last of the most important gaseous products of decomposition
are _sulphuretted_ and _phosphoretted hydrogen_. It is to these gases
that much of the smell of rotting farmyard manure is due.
2. The second class of substances formed are _soluble organic acids_,
such as _humic_ and _ulmic acids_. The function performed by these acids
is a very important one. They unite with the ammonia and the alkali
substances in the mineral portion of the manure, forming humates and
ulmates of ammonia, potash, &c. It is these ulmates that form the black
liquor which oozes out from the manure-heap.
In very rotten farmyard manure traces of _nitric acid_ may be found; but
it must be remembered that the formation of nitrates is practically
impossible under the ordinary conditions of active fermentation of
farmyard manure, except perhaps in its very last stages.
3. The third class of changes taking place have to do with the mineral
portion of the manure. The result of the formation of so much carbonic
and other organic acids is to increase the amount of _soluble_ mineral
matter very considerably.
_Analyses of Farmyard Manure._
It is chiefly to the valuable researches of the late Dr Augustus
Voelcker that we owe our knowledge of the composition of old and fresh
farmyard manure. All interested in this important question should peruse
the original papers on this subject contributed to the 'Journal of the
Royal Agricultural Society' by Dr Voelcker. Typical analyses
illustrating the variation in the composition of farmyard manure at
different stages of decomposition will be found in the Appendix.[164]
From what has been already said, it is obvious chat the composition of
farmyard manure is of a very variable nature.
The quantity of moisture naturally varies most, and this variation will
depend on the age of the manure, and the conditions under which it is
permitted to decay. It may be taken at from a minimum of 65 per cent in
fresh to 80 per cent in well-rotted manure. The total organic matter may
be taken at from 13 to 14 per cent, containing nitrogen .4 to .65 per
cent. The total mineral matter will range from about 4 to 6.5 per cent,
containing of potash from .4 to .7 per cent, and of phosphoric acid from
.2 to .4 per cent.[165]
As Mr Warington[166] has pointed out, one ton of farmyard manure would
thus contain 9 to 15 lb. of nitrogen, about the same quantity of potash,
and 4 to 9 lb. of phosphoric acid. These quantities of nitrogen and
phosphoric acid, calculated to (95 per cent) nitrate of soda, and (97
per cent) sulphate of ammonia, and (25 per cent) superphosphate, give
respectively 57.25 to 96 lb. nitrate of soda, 45 to 75 lb. sulphate of
ammonia, and 35 to 79 lb. superphosphate. That is, in order to apply as
much nitrogen to the soil as is contained in one ton of nitrate of soda,
we should require to use from 23 to 41 tons of farmyard manure:
similarly one ton of sulphate of ammonia contains as much nitrogen as 30
to 50 tons farmyard manure. In the same way one ton of superphosphate
of lime contains as much phosphoric acid as 28 to 64 tons farmyard
manure.
The value of rotten manure is, weight for weight, greater than that of
fresh manure. This is due to the fact that, while the water increases in
amount, the loss of organic matter of a non-nitrogenous nature more than
counterbalances the increase in water. The manure, therefore, becomes
more concentrated in quality. The loss on the total weight, according to
Wolff, in the rotting of farmyard manure, should not exceed in two or
three months' time 16 to 20 per cent--viz., a sixth to a fifth of its
entire weight. Not only, however, does the manure become richer in
manurial ingredients, but the forms in which the manurial ingredients
are present in rotten manure are more valuable, as they are more
soluble. These statements must not be taken as proving that it is more
economical to apply farmyard manure in a rotten condition than in a
fresh one. The distinction must not be lost sight of which exists
between relative increase--increase in the percentage of valuable
constituents--and absolute increase. The increase in the value of the
manure by the changes of the manurial ingredients from the insoluble to
the soluble condition may be effected at the expense of a considerable
amount of absolute loss of these valuable ingredients. This is a point
which is probably too often left out of account in discussing the
relative merits of fresh and rotten farmyard manure; and it is
important that it should be clearly understood. In the words of the late
Dr Voelcker: "Direct experiments have shown that 100 cwt. of fresh
farmyard manure are reduced to 80 cwt. if allowed to lie till the straw
is half rotten; 100 cwt. of fresh farmyard manure are reduced to 60 cwt.
if allowed to ferment till it becomes 'fat or cheesy'; 100 cwt. of fresh
farmyard manure are reduced to 40-50 cwt. if completely decomposed. This
loss not only affects the water and other less valuable constituents of
farmyard manure, but also its most fertilising ingredients. Chemical
analysis has shown that 100 cwt. of common farmyard manure contain about
40 lb. of nitrogen, and that during fermentation in the first period 5
lb. of nitrogen are dissipated in the form of volatile ammonia; in the
second, 10 lb.; in the third, 20 lb. Completely decomposed common manure
has thus lost about one-half of its most valuable constituent."[167]
While, of course, a very great amount of absolute loss of the valuable
constituents--the nitrogen and ash-constituents--of farmyard manure may
take place through volatilisation and drainage, by taking requisite
precautions this loss may be very much minimised. As regards the total
loss, this, in two or three months' time, should only amount to 16 to 20
per cent--or one-sixth to one-fifth of the weight.[168] The use of
fixers, to which reference has already been made, will greatly minimise
this loss. The application of fixers is best made to the manure when
still in the stall or byre. The health of the animal benefits by so
doing, while the manure is at once guarded against loss from this
source.
As to the relative merits of covered and uncovered manure-heaps, much
difference of opinion exists. It is one of those questions which does
not admit of final decision one way or another, as it depends so largely
on the individual circumstances of each case. That manure produced under
cover is more valuable than manure made in the open is readily granted.
The question, however, is as to whether the increase in its value is
sufficiently great to warrant the extra expense involved in building
covered courts. This depends on the individual circumstances of each
case, and cannot be decided in a general way. For experiments on the
relative value of manure made under cover and in the open, see
Appendix.[169]
The method of applying farmyard manure to the field is a question which
belongs more to the practical farmer than, to the scientist, and must be
largely decided by economic considerations. There is an aspect, however,
of the question which may well be treated here. The first point in the
production of good manure is in connection with its even distribution.
It is of great importance that the excrements of the different farm
animals be thoroughly mixed together. By the intimate incorporation of
the "hot" horse-dung with the "cold" cow and pig dung, uniform
fermentation is secured. Fire-fang--or too rapid fermentation--may occur
from this not being properly done, and from the manure becoming too dry.
It is important, also, as we shall see immediately, to have the manure
uniform in quality when applied to the field. The manure ought to be
firmly trodden down, to moderate the rate of fermentation. Where the
manure-heap is exposed to rain, the quantity of water it will naturally
receive will probably be quite sufficient, if indeed not too much, to
ensure a proper rate of fermentation--except, perhaps, in very warm
weather. The great point to be aimed at is to ensure regular
fermentation. What has to be especially avoided is any sudden exposure
of the manure to large quantities of water. The result of such a
washing-out of the soluble nitrogen is to retard fermentation, besides
incurring the risk of great actual loss by drainage.[170]
_Application of Farmyard Manure to the Field._
In applying the manure to the field, and before ploughing it in, two
methods of procedure may be pursued. First, the manure may be set out in
heaps, larger or smaller, over the field, and be allowed to remain in
these heaps some time before being spread; and secondly, it may be
directly spread broadcast over the field, and thus allowed to lie for
some time. Lastly, the manure may be ploughed in immediately; and it may
be stated that such a method is, where circumstances permit, the safest
and most economical method.[171]
In discussing the merits and demerits of these two methods, Dr Heiden
points out, first, with regard to the distribution of the manure in
small heaps over the field, that this is not to be recommended, on the
following grounds:--
1. Because the chances of loss by volatilisation are thereby increased.
The manure is distributed several times instead of only once or twice.
2. It is apt to ensure unequal distribution. The separate heaps run the
risk of losing their soluble nitrogenous matter, which soaks into the
ground beneath the heaps. The other portions of the field not covered by
the manure-heaps are thus manured with washed-out farmyard manure,
bereft of its most valuable constituents. The result is, that while
certain portions of the field are too strongly manured, other portions
are too weakly manured.
3. The proper fermentation of the manure is apt to be interfered with by
the loss of that which is its most important agent--viz., the soluble
nitrogenous matter--and also by the drying action of the wind.
The same objections hold good to a large extent with regard to the
setting out in the fields of the manure in large heaps. The risks of
loss, in one respect, may be said to be less, owing to the smaller
surface presented. On the other hand, they may be greater, owing to
fermentation taking place more quickly. Agricultural practice, however,
often renders this custom necessary; and if precautions are taken not to
let the heap lie too long, and to cover it over with earth, the risk of
serious loss may be rendered inconsiderable.
With regard to the second method of procedure--viz., the spreading of
the manure broadcast over the field, and allowing it thus to lie--Dr
Heiden is of opinion that this should only be done when the field is
level. In the case of uneven ground the risks are, of course, obvious.
It has been affirmed that, by allowing farmyard manure thus to lie
exposed for some time, an important loss of volatile ammonia--carbonate
of ammonia--is apt to take place. This could only take place where the
former treatment of the farmyard manure had been bad. Hellriegel has
shown that in the case of properly prepared farmyard manure there is no
danger of loss in this way. The absorptive power of the soil for
ammonia, it must be remembered, is very great, and the amount of
volatile ammonia in farmyard manure is relatively so small that it is
scarcely possible that any could escape in this way. Hellriegel's
experiments have demonstrated this in a very striking way. He has found
that in the case of a chalky soil, and during the summer and autumn
months, practically no loss of ammonia takes place. The following
considerations may be further urged in support of this method of
application, as against immediately ploughing in the manure, viz.:--
1. That fermentation takes place more quickly.
2. That it results in a more equable distribution of the manurial
constituents in the dung, by gradually and thoroughly incorporating the
liquid portion of the manure with the soil-particles.
Against, however, these undoubted advantages, one serious disadvantage
may be urged--viz., that the manure, before being ploughed in, becomes
robbed to a large extent of its soluble nitrogenous compounds, which, as
we have repeatedly observed, are so necessary for fermentation; and
that, therefore, when it is ploughed in, it does not so readily ferment.
This being so, it is highly advisable, in the case of light or sandy
soils, not to follow such a practice, but to plough the manure directly
in.
As to the depth to which it is advisable to plough the manure in, it may
be here noticed that it should not be too deep, so as to permit of the
access of sufficient moisture to ensure proper fermentation, and to
prevent rapid washing down of nitrates to the drains. Lastly, it need
scarcely be pointed out that it is highly important to have the manure
evenly and thoroughly incorporated with the soil-particles. Where the
manure is permitted to cake together in lumps, it may successfully
resist the action of fermentation for several years.
_Value and Function of Farmyard Manure._
Practical experience has long demonstrated the fact that farmyard manure
is, taking it all round, the most valuable, and admits of the most
universal application, of all manures; and science has done much to
explain the reason of this. The influence of farmyard manure is so
many-sided that it is difficult even to enumerate its different
functions. As has already been pointed out, its indirect value as a
manure is probably as great as, if indeed even not greater than, its
direct value. In concluding our study of farmyard manure, we shall
endeavour to summarise, in as brief a manner as possible, its chief
properties.
First, as to its value as a supplier of the necessary elements of
plant-food. This, there can be little doubt, has been, and still is,
grossly exaggerated by the ordinary farmer. Much has been claimed for it
as a "general" manure. How far it merits pre-eminence on this score
among other manures will be seen in the sequel. It is true that, since
it is composed of vegetable matter, it contains all the necessary plant
ingredients.[172] As has been shown in the Introduction, there is
practically in the case of most soils no necessity to add to a manure
any more than the three ingredients, _nitrogen_, _phosphoric acid_, and
_potash_. Its value, then, as a direct manure, must depend on the
quantity and proportion in which these three ingredients are present.
These substances, as we have already seen, it contains only in very
small quantities. It is, judged from this point of view, a comparatively
poor manure. Furthermore, only a certain percentage of these substances
is in a soluble or immediately available condition,--in this respect the
rotten manure being very much more valuable than the fresh manure.
Again, a point of great importance in a universal manure is the
proportion in which the necessary plant-foods are present. If it be
asked, Are the nitrogen, phosphoric acid, and potash in farmyard manure
present in the proportion in which crops require these constituents? the
answer must be in the negative. Heiden[173] has very strikingly
illustrated this point, in so far as the relations between the two ash
ingredients are concerned, by some computations as to the amount which
would be removed from the soil in the course of different
rotations.[174] In the case of five different rotations it was found
that the ratio between the potash and phosphoric acid removed was as
follows:[175] (1) 2.96 to 1; (2) 2.76 to 1; (3) 2.95 to 1; (4) 4.13 to
1; (5) 3.78 to 1. This would give a mean of 3.32 to 1. This is not the
ratio in which these ingredients are generally present in farmyard
manure. Farmyard manure may be said to be much richer in the mineral
constituents of plants than in nitrogen. Professor Heiden found that in
the case of a farm at Waldau, the crops in the course of ten years
removed from a _morgen_ (.631 of an acre) the following quantities:--
lb.
Nitrogen 329
Potash 263
Phosphoric acid 121
In order to supply these amounts the following quantities of manure
would require to be supplied:--
1. For the nitrogen, 26 or 27 tons (manure containing .606 per cent
nitrogen).
2. For the potash, 20 to 25 tons (manure containing .672 per cent
potash).
3. For the phosphoric acid, 13 to 19 tons (manure containing .315 per
cent phosphoric acid).
From the above it will be seen that farmyard manure contains too little
nitrogen in proportion to its ash ingredients.
It is not merely the amount of fertilising ingredients removed by the
crop we have to take into account in estimating the value of certain
manurial ingredients for the different crops. Two other considerations
have to be remembered--viz., the amount of the constituents already
present in the soil, and the ability of the different crops to obtain
the ingredients from the soil. If we take into account these two
considerations in estimating the value of farmyard manure as a general
manure, we shall find that they accentuate the inadequacy of the ratio
existing between the nitrogen and the mineral ingredients. Messrs Lawes
and Gilbert have found in the Rothamsted experiments with farmyard
manure, that while it restored the mineral ingredients, it was
inadequate as a sufficient source of nitrogen. Nitrogen is, of all
manurial ingredients, in least abundance in soils. It is consequently
found that the ingredient in which farmyard manure requires to be
reinforced is nitrogen. With regard to phosphoric acid and potash, it
has already been shown that the ratio between them is probably greater
than that in a good average manure. We should, arguing from this alone,
be inclined to think that farmyard manure would be best reinforced with
potash. The reverse is the case, however, as every farmer knows. This is
due, first, to the fact that the potash, unlike the phosphoric acid, is
entirely of a soluble nature, and therefore immediately available for
the plant's needs; and secondly, to the fact that the necessity for the
application of potash as a manure is generally not nearly so great as in
the case of phosphoric acid. The result is, that farmyard manure will
be, as a rule, more valuably supplemented by phosphoric acid than by
potash.
Another point of great importance, in estimating the value of farmyard
manure as a chemical manure, is the inferior value possessed by much of
the nitrogen it contains, as compared with the nitrogen in such
artificial manures as nitrate of soda and sulphate of ammonia. According
to the Rothamsted experiments, weight for weight, the nitrogen in
farmyard manure is not half so valuable as it is in sulphate of ammonia.
Much of the nitrogen becomes only very slowly available; not a little of
it perhaps actually takes years to be converted into nitrates.[176]
Thus, with regard to the direct value of farmyard manure as a manure, we
have seen--
1. That it contains a very small quantity of the three fertilising
ingredients.
2. That the proportion in which these three ingredients are present is
not the best proportion for the requirements of crops.
3. That the form in which a portion of these ingredients--nitrogen and
phosphoric acid--is present is not of the most valuable kind.
It is consequently not as a direct chemical manure that farmyard manure
is pre-eminently valuable. We must seek for perhaps its most valuable
properties in its indirect influence.
It adds to the soil a large quantity of organic matter. Most soils are
improved by the addition of _humus_. The water-absorbing and retaining
powers of a soil are increased by this addition of _humus_, while it
enables the soil to attract an increased amount of moisture from the
air. This is often of great importance, as in the period of germination
of seed.[177] The influence it exerts on the texture of the soil in the
process of fermentation is also very great. This is especially so in
soils whose texture is too close, such as heavy clayey soils. It opens
up their pores to the air, and renders them more friable. Where such an
influence is most required, as in clayey soils, the manure ought to be
applied in a fresh condition, so that the maximum influence exerted by
the manure in this direction may be experienced. On light soils, on the
contrary, whose friability and openness are already too great, and which
do not require to be increased, the manure will be best applied in a
rotten condition. It adds, further, greatly to the heat of the soils by
its decomposition. Thus on cold damp soils it effects one very marked
benefit. The influence it exerts in its decomposition upon the
fertilising ingredients present in the soil is also by no means
inconsiderable. In the process of its fermentation large quantities of
carbonic acid gas are generated. This carbonic acid probably acts in a
double capacity. It will, in the first place, greatly increase the
solvent power of the soil-water, and thus enable it to set free an
increased amount of mineral plant-food; and secondly, it will help to
conserve a certain quantity of the soil-nitrogen, by preventing its
conversion into nitrates.
As its indirect and mechanical properties are greatest when in its fresh
condition, it will be better to apply it in that condition to soils most
lacking in these mechanical properties. We may therefore say that
farmyard manure is best applied in a rotted condition to light sandy
soils, and to soils in a high state of cultivation, where its mechanical
properties are not so much required.
An important point still remains to be discussed--viz., the rate at
which the farmyard manure should be applied. This, of course, should
naturally depend on a variety of circumstances--the amount of artificial
manures used as supplementary to the farmyard manure, the frequency of
its application, and the nature of the soil.
These considerations naturally vary so much, that the quantities of
farmyard manure it is advisable to apply in different cases are widely
different. There is a strong probability that the rate at which farmyard
manure has been applied in the past has been grossly in excess of what
could be profitably employed. Opinion is gaining ground among practical
farmers, that smaller and more frequent applications of farmyard manure
to the soil would be fraught with better results than the older custom
of applying a large dressing at a time. This is an opinion in the
support of which science can urge strong arguments. It is only of late
years that we have come to recognise sufficiently the various risks
which all fertilisers are subject to in the soil, and the importance,
therefore, of minimising these risks as much as possible by putting into
the soil at one time only as much manure as it is safely able to retain.
"The famous old German writer Thaer regarded 17 or 18 tons as an
abundant dressing; 14 tons he called good, and 8 or 9 tons light. Other
German authorities speak of 7 to 10 tons as light, 12 to 18 tons as
usual, 20 or more tons as heavy, and 30 tons as a very heavy
application."[178]
In the new edition of Stephens' 'Book of the Farm,'[179] from 8 to 12
tons per acre for roots, and from 15 to 20 tons for potatoes, along with
artificials, which may cost from 25s. to 60s. per acre additional, are
quoted as general dressings.
The majority of recent experiments with farmyard manure would seem to
indicate that, even in the case of what are considered small dressings,
the extra return in crop the first year after application is not such as
to cover the expense of the manure. Of course, as is commonly pointed
out, the effect of farmyard manure is of a lasting nature, and is
probably felt throughout the whole rotation, or even longer. This, to a
certain extent, is no doubt true; still it may be strongly doubted
whether farmyard manure is, after all, an economical manure, as compared
with artificial manures. The desirability of manuring the soil and not
the crop is, in this age of keen competition, no longer believed in; and
the Rothamsted experiments have shown that it is highly doubtful whether
even the soil benefits to anything like a commensurate extent by the
application of large quantities of farmyard manure. This is of course
assuming for farmyard manure the value that it would fetch when sold,
or, to put it rather differently, the price it would cost if the farmer
had to purchase it. Farmyard manure is a necessary bye-product of the
farm, and can scarcely be regarded, therefore, in the same light as the
artificial manures which the farmer buys.[180]
FOOTNOTES:
[131] See Appendix, Note I., p. 279.
[132] "The large amount of potash in unwashed wool is very remarkable: a
fleece must sometimes contain more potash than the whole body of the
shorn sheep."--Warington's 'Chemistry of the Farm,' p. 78.
[133] See Appendix, Note II., p. 279.
[134] The urine of the pig, from the nature of its food, is, as a
general rule, a very poor nitrogenous manure.
[135] See Appendix, Note XV., p. 290.
[136] See Appendix, Note III., p. 280.
[137] See Appendix, Note XVIII., p. 291.
[138] The nitrogen present in the urine, it may be well to point out, is
derived from the waste of nitrogenous tissue as well as from nitrogenous
matter of the food digested.
[139] Note IV., p. 281.
[140] Warington puts this matter admirably in the following words: "If
the food is nitrogenous and easily digested, the nitrogen in the urine
will greatly preponderate. If, on the other hand, the food is one
imperfectly digested, the nitrogen in the solid excrement may form the
larger quantity. When poor hay is given to horses, the nitrogen in the
solid excrement will exceed that contained in the urine. On the other
hand, corn, cake, and roots yield a large excess of nitrogen in the
urine." ('Chemistry of the Farm,' p. 137).
[141] See p. 281.
[142] See p. 282.
[143] See Heiden's 'Duengerlehre,' vol. ii. p. 58.
[144] Heiden's 'Duengerlehre,' vol. i. p. 404.
[145] The following quantities of nitrogen are found in rye, pea, and
bean straw:--
Ranging from Average Lb.
per cent. per cent. per ton.
Rye-straw .30 to .73 .57 12.76
Pea-straw .76 to 1.61 1.21 27.10
Bean-straw 1.15 to 2.62 1.92 43.00
[146] Dr J. M. H. Munro recommends the sprinkling of a little finely
sifted peat-powder in addition to straw, as an excellent means of
preventing loss of volatile ammonia in the fermentation of manure.
[147] See 'Mark Lane Express,' October 7, 1889, p. 475.
[148] See Appendix, Note VII., p. 283.
[149] For analyses see Appendix, Note VIII., p. 283.
[150] According to Storer, in a ton of autumn leaves of the best quality
there would be 6 lb. of potash, less than 3 lb. of phosphoric acid, and
10 or 15 lb. of nitrogen. Another substance that may be used as a litter
is sawdust. This substance is a good absorbent, but is of little value
as a manurial substance.
[151] Heiden's 'Duengerlehre,' vol. ii. pp. 34, 66. In Boussingault's
experiments the food consisted of 15 lb. _hay_, 4.54 lb. _oats_, and 32
lb. water; the total excrements amounting to 31.16 lb., containing 7.42
lb. dry matter. In Hofmeister's experiments the food consisted of 5.23
lb. _hay_, 6.18 lb. _oats_, 1 lb. _chopped straw_, and 25.57 lb. water;
the excrements amounting to 25.07 lb., containing 5.32 lb. dry matter.
[152] This is taking no account of the amount of water which the manure
will absorb, and which will probably double the quantity.
[153] See Appendix, Note IX., p. 283.
[154] The rapid fermentation of horse-manure is due to its mechanical as
well as its chemical nature. The horse does not reduce its food to such
small pieces, and its urine is rich in nitrogen.
[155] Schulze recommends one-third of a pound per day of sulphate of
lime for each horse.
[156] See Appendix, Note X., p. 284.
[157] The food consisted of 30 lb. _potatoes_, 15 lb. _hay_, and 120 lb.
_water_.
[158] For further analyses of cow-manure, see Appendix, Note XI., p.
286.
[159] This is for a pig of six to eight months old, and fed on potatoes.
[160] It has been asserted that the use of pig-manure, when applied
alone, is apt to give an unpleasant taste to the produce grown.
[161] Taken from a very large number of analyses by a number of
experimenters. See Heiden's 'Duengerlehre,' vol. i. p. 99.
[162] See Storer, 'Agricultural Chemistry,' vol. ii. p. 96.
A question of great importance is as to the amount of farmyard manure
produced on a farm in a year, and its value. This is a question which is
extremely difficult to satisfactorily deal with. Various methods of
calculating this amount have been resorted to. It may be well to state
these pretty fully. Some practical authorities estimate the amount by
calculating that every ton of straw should produce 4 tons of manure.
Another method consists in estimating the amount from the size of the
farm. Sir John Lawes has calculated the composition of farmyard manure
which should be produced in the case of a farm of 400 acres, farmed on
the four-course system. He assumes that half of the roots and 100 tons
of hay are consumed at the homestead; that the whole of the straw of the
corn crops is retained at home as food and litter; that twelve horses
have corn equal to 10 lb. of oats per head per day; and that about ten
shillings per acre are expended in the purchase of cake for feeding
stock. Under these conditions the amount of farmyard manure should be
855 tons (or an average of 8-1/2 tons for each of the 100 acres of
root-crop) of _fresh undecomposed dung_. (For composition, see Appendix,
Note XVII., p. 291.) Another method is by taking, as the data of
calculation, the number of cattle, horses, sheep, &c., producing the
manure. Lloyd considers that a fattening animal requires 3 tons of straw
in the year, and makes about 12 tons of manure. A farmer, therefore,
should make 8 tons of manure for every acre of that part of his land
which, in the four-course rotation, is put down to turnips.
The last method consists in taking as the data the amount of food
consumed and litter used in the production of the manure. Of these
methods Heiden considers the last as alone satisfactory and trustworthy.
Applying this method to the horse, he shows, from experiments, that a
little over 47 per cent of the dry matter of its food has been proved to
be voided in the solid and liquid excreta. Taking the average percentage
of water in the excreta as about 77.5, the percentage of dry matter in
the excreta will be 22.5. That is, every pound of dry matter in the food
eaten by the horse yields a little over 2 lb. of excrementitious matter.
To this of course must be added the amount of straw used as litter,
which may be taken at 6.5 lb.
From these data we may calculate the amount of manure produced in a year
by a horse, making certain assumptions as to the amount of work
performed. This Heiden does by assuming that a horse works 260 days, of
twelve hours each, in the course of a year, or 130 whole days, spending
235 days in the stall. Calculating from the above data, he estimates
that a well-fed working horse will produce about 50 lb. of manure in a
day, or 6.5 tons in a year. Of course this does not necessarily
represent all the manure actually produced by the horse, but how much of
the remaining portion of the manure actually finds its way to the farm
it is impossible to say. According to the 'Book of the Farm,' Division
III. p. 98, a farm-horse makes about 12 tons of manure in a year.
It has been calculated that cows void about 48 per cent of the dry
matter of their food in the solid and liquid excreta, which contain of
water, on an average, 87.5 per cent. That is, every pound of dry matter
will furnish 3.84 lb. of total excreta. By adding the necessary amount
of straw for litter (which may be taken at one-third the weight of the
dry matter of the fodder), Heiden calculates that an ox weighing 1000
lb. should produce 113 lb. of manure in a day, or 20 tons in a year. The
'Book of the Farm,' Division III. p. 98, gives the annual amount at from
10 to 14 tons. According to Wolff, one may assume that on an average the
fresh excrements (both liquid and solid) of the common farm animals
(with the exception of the pig) contain of every 100 lb. of dry matter
in the food consumed about 50 lb., or a half. Estimating the dry matter
in the litter used at equal to about 1/4 of the dry matter of the food,
this would mean that for every 100 lb. of dry matter consumed in food
there would be 75 lb. of dry manure (viz., 50 lb. dry excrements + 25
lb. dry litter), which would yield 300 lb. of farmyard manure in the wet
state--_i.e._, with 75 per cent water. The amount of food daily required
per every 1000 lb. of live-weight of the common farm animals may be
taken, roughly speaking, at 24 lb. dry food material and 6 lb. of straw
as litter. The daily production of manure for 1000 lb. of live-weight
would amount, therefore, to 18 lb. of dry, or 72 lb. wet manure. (See
Appendix, Note XVII., p. 291.) According to J. C. Morton and Evershed,
oxen feeding in boxes require 20 lb. of straw per head per day as
litter. An ox, therefore, will make 8 tons of fresh dung in six months,
using 32 cwt. of litter. This means that each ton of litter gives 5 tons
of fresh dung. It is calculated that nearly twice as much litter must be
used in open yards.
[163] It has been calculated that under ordinary circumstances
sheep-dung, when allowed to ferment by itself, should do so in about
four months, horse-dung in six months, and cow-dung in eight months.
[164] See Appendix, Note XII., p. 286.
[165] See Heiden's 'Duengerlehre,' vol. ii. p. 156.
[166] Warington, 'Chemistry of the Farm,' p. 33.
[167] Recent experiments by Muentz and Girard in France have shown that
the loss in sheep excreta from volatilisation of the carbonate of
ammonia amounted to over 50 per cent. By the use of straw litter this
was reduced to about a half less, and with earth litter one quarter
less.
[168] See Appendix, Note XIII., p. 288.
[169] See Appendix, Note XIV., p. 289.
[170] See Appendix, Note XV., p. 290.
[171] For spring application rotten farmyard manure is generally used,
because in this condition its fertilising matter is more quickly
available. On light land it is best to apply it in the rotten condition
shortly before it is likely to be used. (See p. 261.)
[172] The total amount of plant-food in a ton of farmyard manure is
together less than 1/20th of its total weight.
[173] See Heiden's 'Duengerlehre,' vol. ii. p. 171.
[174] For full details see Appendix, Note XVI., p. 290.
[175] Storer reproduces these results in his 'Agricultural Chemistry,'
vol. ii. p. 21.
[176] This aspect of farmyard manure has been ably stated by Mr F. J.
Cooke, a well-known Norfolk farmer. In commenting on the results of the
Rothamsted experiments, he says: "It is clear enough that the faith of
the farmer in the soil-enriching character of his home-made manure is
amply justified; the only question being, indeed, if this quality be not
too highly appreciated. It is not, after all, so much by the fattening
of our land as by the bounty of the crop grown upon it that we reap the
fruit of our exertions. The man of scientific mind keeps his purpose
fixed on the _production of good crops_ mainly, and the cheapest way to
grow them. The experiments under consideration show that richness of
land may be purchased much too dearly, and that richness of crop by no
means bears the necessary relation to richness of soil which has
sometimes been imagined. We may boast of the 'lasting qualities' of our
dung, but the answer of science by these experiments is, that so great
is the last that the life of one man may not be long enough to exhaust
it. In the extravagant use of dung, therefore, such considerations,
amongst many others, as length of purse, as well as length and character
of tenure, must clearly be taken into account."
[177] See paper on "Manurial Experiments with Turnips" by author, in
'Transactions of the Highland and Agricultural Society of Scotland;'
1891.
[178] Storer's 'Agricultural Chemistry,' vol. i. p. 498.
[179] Division III. p. 130.
[180] Mr F. J. Cooke, who has already been quoted, has kindly furnished
the author with his views on the peculiar functions of farmyard manure
as a manure. He says: "I look upon it, broadly speaking, as chiefly of
value in restoring to good land, after cropping, those particular
advantages which good land alone can give, and in helping better than
any other manure, when applied to poor land, to bring it up to the level
of good land in those particular merits which belong alone to fine
soils. I speak now of an inherent value in good soils, beyond that
attaching to them as mere reservoirs of abundant plant-food. For
instance, one may supply a poor soil by artificial manure with much more
food--and in a highly soluble condition--than is needed by the crop to
be grown upon it, and yet not get so good a crop as upon a naturally
richer but otherwise similar soil less abundantly filled with
immediately available food. This may arise from a more perfect
distribution of the plant-food in the rich soil, or from the steady way
in which it becomes available to the crop, as well as for other reasons.
But whatever the cause, there, I think, is the broad fact of the power
of farmyard manure to enrich poor soils, so to speak, more
naturally--that is, in a way which makes them more nearly correspond to
better soils than artificial manures can."
Hence the indirect benefit to the farmer from farmyard manure is
probably greater than its direct value as a mere manure. And the usual
provision and use of it amongst all straw-growing farmers is
sufficiently justified. The extent, however, to which that course may be
beneficially carried, is one of the most important of the many difficult
economic and scientific problems which the farmer has to face.
On the economic side must of course be considered the cost of
manufacture in individual instances, as ruled by the market value of the
straw, and the different circumstances and conditions under which the
various farm animals are kept and fed (I have the figures by me of one
well-known farmer, which show the cost to him of every ton of home-made
manure to be 20s. or more); the price the resultant crops may be
expected to command; the cost at the moment of artificial manures, &c.,
&c. Whilst on the scientific side must be considered the nature of the
soil, the particular rotation of crops, &c.
It was, amongst others, just these scientific and yet very definite and
practical problems we have tried to throw light on in the series of
field experiments conducted for several years by the Norfolk Chamber of
Agriculture. (See reprint of summary of same in last year's Report of
the Board of Agriculture.)
APPENDIX TO CHAPTER VII.
NOTE I. (p. 225).
DIFFERENCE IN AMOUNT OF EXCRETA VOIDED FOR FOOD CONSUMED.
With regard to the difference in the composition of the solid excreta
voided by different fattening animals fed on the same amount of food,
see Warington's 'Chemistry of the Farm,' p. 125, where it is shown that
for equal amount of live-weight, the sheep produces on the same weight
of dry food very much more manure than the pig, while the ox produces
even more than the sheep. Of course this does not refer to the total
amount of manure produced by the different animals, but only to the
amount of manure produced from the consumption of equal quantities of
food. This would seem to be owing to the greater capacity the pig has
for assimilating its food.
NOTE II. (p. 227).
SOLID EXCRETA VOIDED BY SHEEP, OXEN, AND COWS.
To contrast with the analyses given by Stoeckhardt, it may be well to
cite those based on Lawes and Gilbert's experiments, and quoted by
Warington ('Chemistry of the Farm,' p. 138):--
I.--SHEEP (fed on _meadow-hay_).
SOLID EXCREMENT.
Fresh. Dry.
Water 66.2 -
Organic matter 30.3 89.6
Ash 3.5 10.4
---- ----
Nitrogen .7 2.0
II.--OXEN (fed on _clover-hay_ and _oat-straw_, with 8 lb.
_beans_ per day).
Fresh. Dry.
Water 86.3 -
Organic matter 12.3 89.7
Ash 1.4 10.3
---- ----
Nitrogen .3 1.9
III.--COWS (fed on _mangels_ and _lucerne hay_).
Mangels. Lucerne hay.
Water 83.00 79.70
Nitrogen .33 .34
Phosphoric acid .24 .16
Potash .14 .23
NOTE III. (p. 232).
URINE VOIDED BY SHEEP, OXEN, AND COWS.
The following are the results for urine, the animals being fed as in
Note II.:--
Sheep. Oxen.
Fresh. Dry. Fresh. Dry.
Water 85.7 - 94.1 -
Organic matter 8.7 61.0 3.7 63.0
Ash 5.6 39.0 2.2 37.0
---- ---- ---- ----
Nitrogen 1.4 9.6 1.2 20.6
Cows.
Mangels. Lucerne hay.
Water 95.94 88.25
Nitrogen .12 1.54
Phosphoric acid .01 .006
Potash .59 1.69
NOTE IV. (p. 233).
PERCENTAGE OF FOOD VOIDED IN THE SOLID AND LIQUID EXCREMENTS.
According to Wolff, the following table shows the percentage of the dry
substance of the food which is voided in the solid and liquid excrements
of the cow, ox, sheep, and horse:--
Cow. Ox. Sheep. Horse. Average.
Solid excreta 38.0 44.0 42.6 46.7 42.8
Urine 5.8 6.3 6.8 5.7 6.2
---- ---- ---- ---- ----
Total 43.8 50.3 49.4 52.4 49.0
NOTE V. (p. 234).
PIG EXCREMENTS.
The excrements voided by pigs are poor in manurial constituents, because
the food on which they are fed is generally of a very poor nature. In
their case the urine is always very much richer in manurial ingredients
than the solid excreta. The relative composition of the solid excreta
and the urine will be best illustrated by quoting some experiments
carried out by Wolff on this subject. The experiments were carried out
with two pigs nine and a half months old, and each 121.9 kilogrammes (a
kilogramme is equal to about 2-1/4 lb.) in weight. The first consumed
daily 1000 grammes of barley, 5000 grammes of potatoes, and 2572 grammes
of sour-milk. The second one consumed the same quantities of potatoes
and sour-milk as the first, and 1000 grammes of peas. The following
table gives the results of excreta and urine daily voided, in grammes:--
Dry Nitrogen. Ash. Potash. Lime. Magnesia. Phosphoric
substance acid.
Solid { I. 217.7 8.7 28.6 7.3 4.4 3.0 10.3
excreta { II. 161.1 9.1 31.1 5.9 4.9 2.8 11.1
Urine { I. 112.8 19.3 56.2 33.0 0.4 0.9 6.7
{ II. 137.7 30.6 62.2 37.1 0.2 1.1 7.1
NOTE VI.(p. 236).
MANURIAL CONSTITUENTS IN 1000 PARTS OF ORDINARY FOODS.
Based on Lawes and Gilbert's Analyses.
(Warington's 'Chemistry of the Farm,' p. 139.)
-----------------------------+---------+-----------+---------+------------
| Dry | Nitrogen. | Potash. | Phosphoric
| matter. | | | acid.
-----------------------------+---------+-----------+---------+------------
Cotton-cake, decorticated | 918 | 70.4 | 15.8 | 30.5
Rape-cake | 887 | 50.5 | 13.0 | 20.0
Linseed-cake | 883 | 43.2 | 12.5 | 16.2
Cotton-cake, undecorticated | 878 | 33.3 | 20.0 | 22.7
Linseed | 882 | 32.8 | 10.0 | 13.5
Palm-kernel meal, English | 930 | 25.0 | 5.5 | 12.2
Beans | 855 | 40.8 | 12.9 | 12.1
Peas | 857 | 35.8 | 10.1 | 8.4
Malt-dust | 905 | 37.9 | 20.8 | 18.2
Bran | 860 | 23.2 | 15.3 | 26.9
Oats | 870 | 20.6 | 4.8 | 6.8
Rice-meal | 900 | 19.1 | 6.1 | 23.8
Wheat | 877 | 18.7 | 5.2 | 7.9
Rye | 857 | 17.6 | 5.8 | 8.5
Barley | 860 | 17.0 | 4.7 | 7.8
Maize | 890 | 16.6 | 3.7 | 5.7
Brewers' grains | 234 | 7.8 | 0.4 | 3.9
Clover-hay | 840 | 19.7 | 18.6 | 5.6
Meadow-hay | 857 | 15.5 | 16.0 | 4.3
Bean-straw | 840 | 13.0 | 19.4 | 2.9
Oat-straw | 857 | 6.4 | 16.3 | 2.8
Barley-straw | 857 | 5.6 | 10.7 | 1.9
Wheat-straw | 857 | 4.8 | 6.3 | 2.2
Potatoes | 250 | 3.4 | 5.8 | 1.6
Swedes | 107 | 2.2 | 2.0 | 0.6
Carrots | 140 | 2.1 | 3.0 | 1.1
Mangels | 120 | 1.8 | 4.6 | 0.7
Turnips | 80 | 1.6 | 2.9 | 0.8
-----------------------------+---------+-----------+---------+------------
NOTE VII. (p. 241).
ANALYSES OF STABLE-MANURE, MADE RESPECTIVELY WITH PEAT-MOSS LITTER
AND WHEAT-STRAW (by BERNARD DYER, B.Sc.)
Peat-moss litter. Wheat-straw.
Per cent. Per cent.
Total nitrogen 0.88 0.61
Equal to ammonia 1.07 0.74
Phosphoric acid 0.37 0.43
Equal to Tribasic phosphate of
lime (or Tricalcic phosphate) 0.80 0.94
Potash 1.02 0.59
NOTE VIII. (p. 242).
ANALYSES OF BRACKEN (by J. HUGHES, F.C.S.)
No. 1 No. 2
Young fern. Old fern.
Per cent. Per cent.
Water 11.66 14.90
* Organic matter 83.38 80.54
+ Mineral matter 4.96 4.56
------ ------
100.00 100.00
------ ------
Containing--
* Nitrogen 2.42 0.90
+ Silica 1.60 2.81
Potash 1.15 0.10
Soda 0.64 0.26
Lime 0.44 0.62
Magnesia 0.13 0.47
Phosphoric acid 0.60 0.30
NOTE IX. (p. 244).
ANALYSES OF HORSE-MANURE.
For a fuller discussion of this question, the reader is referred to
Heiden's 'Duengerlehre,' vol. ii. p. 185, and also to Storer's
'Agricultural Chemistry,' vol. i. p. 575. The statements in the
different text-books as to the quantity of manure produced by the horse
are such as naturally to perplex the student. This discrepancy is due,
however, to the different methods adopted by different writers of
calculating this amount. The subject is further discussed in the
footnote to p. 252. The following analyses of horse-manure may be
valuable for reference. They are taken from Storer's 'Agricultural
Chemistry,' vol. i. p. 496:--
----------------+-------+-------+-------+-------+-------+---------
| 1. | 2. | 3. | 4. | 5. | Average.
----------------+-------+-------+-------+-------+-------+---------
Water | 75.76 | 69.30 | 67.23 | 72.13 | 71.30 | 71.15
Dry matter | 24.24 | 24.82 | 32.72 | 27.87 | 28.70 | 27.67
Ash ingredients | 5.07 | 5.05 | 6.49 | 3.37 | 3.30 | 4.65
Potash | 0.51 | 0.63 | 0.22 | 0.59 | 0.53 | 0.49
Lime | 0.30 | 0.74 | 0.17 | 0.41 | 0.21 | 0.36
Magnesia | 0.19 | 0.29 | 0.20 | 0.17 | 0.14 | 0.20
Phosphoric acid | 0.41 | 0.67 | 0.35 | 0.12 | 0.28 | 0.36
Ammonia | 0.26 | 0.12 | 0.15 | 0.44 | - | 0.24
Total nitrogen | 0.53 | 0.69 | 0.47 | 0.67 | 0.58 | 0.59
----------------+-------+-------+-------+-------+-------+---------
NOTE X. (p. 247).
THE NATURE OF THE CHEMICAL REACTIONS OF AMMONIA "FIXERS."
For the student, the exact nature of the chemical reactions taking place
may be of interest.
In the first place, it must be distinctly understood that the form in
which ammonia escapes from the manure-heap is not, as is so commonly
erroneously stated in agricultural text-books, as "free" ammonia.
Whenever ammonia is brought into contact with carbonic acid, carbonate
of ammonia is formed. When it is remembered that carbonic acid is by far
the most abundant of the gaseous products of the decomposition of
organic matter, it will be at once seen that free ammonia could not
exist under such circumstances.
1. In the case of _hydrochloric acid_, the following chemical equation
will represent the nature of the reaction--
2HCl + (NH_{4})_{2}CO_{3} = 2NH_{4}Cl + H_{2}O+CO_{2}
(Hydrochloric (carbonate of ammonia,) (sal-ammoniac,) (carbonic acid.)
acid,)
2. In the case of _sulphuric acid_, the equation will be--
H_{2}SO_{4} + (NH_{4})_{2}CO_{3} = (NH_{4})_{2}SO_{4} + H_{2}O+CO_{2}
(Sulphuric (carbonate of (sulphate of ammonia,) (carbonic acid.)
acid,) ammonia,)
3. With _gypsum_ (CaSO_{4})--
CaSO_{4} + (NH_{4})_{2}CO_{3} = CaCO_{3} + (NH_{4})_{2}SO_{4}
(Gypsum,) (carbonate of (calcium (sulphate of ammonia.)
ammonia,) carbonate,)
4. With _copperas_ (FeSO_{4})--
FeSO_{4} + (NH_{4})_{2}CO_{3} = FeCO_{3} + (NH_{4})_{2}SO_{4}
(Sulphate of (carbonate of (ferrous (sulphate of ammonia.)
iron,) ammonia,) carbonate,)
5. With _sulphate of magnesia_ (MgSO_{4})--
MgSO_{4} + (NH_{4})_{2}CO_{3} = MgCO_{3} + (NH_{4})_{2}SO_{4}
(Sulphate of (carbonate of (carbonate of (sulphate of
magnesia,) ammonia,) magnesia,) ammonia.)
Reference has been made to the fact that magnesium sulphate may probably
not only fix the ammonia, but the phosphoric acid. When magnesium
sulphate, soluble phosphoric acid, and ammonia are brought in contact
with one another, the double insoluble phosphate of ammonium and
magnesium (MgNH_{4}PO_{4}6Aq) is formed. While such a reaction is
possible, it is highly improbable that it takes place to any extent. The
double phosphate is a crystalline salt which only separates after a
considerable time, and in the presence of a large excess of ammonia.
NOTE XI. (p. 250).
ANALYSES OF COW-MANURE.[181]
----------------+-------+-------+-------+-------+-------+-------+--------
| 1. | 2. | 3. | 4. | 5. | 6. |Average.
+-------+-------+-------+-------+-------+-------+--------
Water | 85.30 | 77.71 | 74.02 | 72.87 | 75.00 | 77.50 | 77.06
Dry matter | 14.70 | 22.30 | 25.98 | 27.13 | 25.00 | 22.50 | 22.93
Ash ingredients | 2.04 | 4.71 | 3.94 | 6.70 | 6.22 | 2.20 | 4.30
Potash | 0.36 | 0.46 | 0.56 | 1.69 | 0.39 | 0.40 | 0.64
Lime | 0.29 | 0.37 | 0.58 | 0.41 | 0.24 | 0.31 | 0.48
Magnesia | 0.19 | 0.11 | 0.13 | - | 0.18 | 0.11 | -
Phosphoric acid | 0.16 | 0.13 | 0.07 | 0.20 | 0.14 | 0.16 | 0.14
Ammonia | 0.06 | 0.16 | 0.07 | - | 0.27 | - | 0.14
Total nitrogen | 0.38 | 0.54 | 0.41 | 0.79 | 0.46 | 0.34 | 0.48
----------------+-------+-------+-------+-------+-------+-------+--------
NOTE XII. (p. 259).
COMPOSITION OF FRESH AND ROTTEN FARMYARD
MANURE (VOELCKER).
Composition of fresh manure, composed of horse, cow,
and pig dung, about fourteen days old:--
Water 66.17
* Soluble organic matter 2.48
Soluble inorganic matter 1.54
+ Insoluble organic matter 25.76
Insoluble inorganic matter 4.05
------
100.00
------
* Containing nitrogen .149
Equal to ammonia .181
+ Containing nitrogen .494
Equal to ammonia .599
Total percentage of nitrogen .643
Equal to ammonia .780
Ammonia in a volatile state .034
Ammonia in form of salts .088
Composition of the whole ash:--
Soluble in water, 27.55 per cent:--
Soluble silica 4.25
Phosphate of lime 5.35
Lime 1.10
Magnesia 0.20
Potash 10.26
Soda 0.92
Chloride of sodium 0.54
Sulphuric acid 0.22
Carbonic acid and loss 4.71
Insoluble in water, 72.45 per cent:--
Soluble silica 17.34
Insoluble silicious matter 10.04
Oxide of iron and alumina with phosphates 8.47
(Containing phosphoric acid, 3.18 per cent.)
(Equal to bone-earth, 6.88 per cent.)
Lime 20.21
Magnesia 2.56
Potash 1.78
Soda 0.38
Sulphuric acid 1.27
Carbonic acid and loss 10.40
------
100.00
-------
Composition of rotten dung, six months old, is as
follows:--
Water 75.42
* Soluble organic matter 3.71
Soluble inorganic matter 1.47
+ Insoluble organic matter 12.82
Insoluble inorganic matter 6.58
------
100.00
------
* Containing nitrogen .297
Equal to ammonia .360
+ Containing nitrogen .309
Equal to ammonia .375
Total amount of nitrogen .606
Equal to ammonia .735
Ammonia in a volatile state .046
Ammonia in form of salts .057
Composition of the whole ash:--
Soluble in water, 18.27 per cent:--
Soluble silica 3.16
Phosphate of lime 4.75
Lime 1.44
Magnesia 0.59
Potash 5.58
Soda 0.29
Chloride of sodium 0.46
Sulphuric acid 0.72
Carbonic acid and loss 1.28
Insoluble in water, 81.73 per cent:--
Soluble silica 17.69
Insoluble silica 12.54
Phosphate of lime -
Oxides of iron alumina with phosphates 11.76
(Containing phosphoric acid, 3.40 per cent.)
(Equal to bone-earth, 7.36 per cent.)
Lime 20.70
Magnesia 1.17
Potash 0.56
Soda 0.47
Chloride of sodium -
Sulphuric acid 0.79
Carbonic acid and loss 16.05
------
100.00
------
NOTE XIII. (p. 263).
COMPARISON OF FRESH AND ROTTEN MANURE (WOLFF).
Fresh. Moderately rotten
(Taking the quantity of dry matter
as the same.)
Dry matter 25.00 25.00
Ash 3.81 4.76
Nitrogen 0.39 0.49
Potash 0.45 0.56
Lime 0.49 0.61
Magnesia 0.12 0.15
Phosphoric acid 0.18 0.23
Sulphuric acid 0.10 0.13
Silica 0.86 1.08
NOTE XIV. (p. 263).
LORD KINNAIRD'S EXPERIMENTS.[182]
"Lord Kinnaird has given the particulars of a very careful experiment.
He tried to test the comparative value of manure kept in an open court
with that kept under cover. He selected the same kind of cattle, gave
them the same kind and quantity of food, and bedded them with the same
kind of straw. A field of 20 acres of uniform land was selected. This
having been equally divided, 2 acres out of each 10 gave the following
results:--
_Potatoes grown with Uncovered Manure._
Tons. cwt. lb.
First measurement--1 acre produced. 7 6 8
Second do. do. do. 7 18 99
_Potatoes grown with Covered Manure._
First measurement--1 acre produced. 11 17 56
Second do. do. do. 11 12 26
This shows an increase of about 4 tons of potatoes per acre with the
covered manure.
"The next year the weather was wet, grain soft and not in very good
order, but the following was the amount of produce:--
_Wheat grown with Uncovered Manure._
Weight per
Produce in grain. bushel. Produce in straw.
Acre. bushels. lb. lb. stones. lb.
First 41 19 61-1/2 152 of 22
Second 42 38 61-1/2 160 of 22
_Wheat grown with Covered Manure._
First 53 5 61 220 of 22
Second 53 47 61 210 of 22"
NOTE XV. (pp. 231, 264).
DRAININGS OF MANURE-HEAPS.
The importance of not separating the liquid portion from the solid
portion has already been pointed out in dealing with the composition of
the solid excreta and the urine. These two constituents of the manure
are complementary to one another, and the value of farmyard manure as a
general manure is very much impaired if the liquid portion is not
applied along with the solid. In one important respect do the drainings
of manure-heaps differ from urine--that is, in the percentage of
phosphates they contain, the latter being practically devoid of
phosphoric acid.
The following is an analysis of drainings from a manure-heap (Wolff):--
Dry substance 18.0 | Magnesia 0.4
Ash 10.7 | _Phosphoric acid_ 0.1
Nitrogen 1.5 | Sulphuric acid 0.7
Potash 4.9 | Silica 0.2
Lime 0.3 |
NOTE XVI. (p. 270).
AMOUNTS OF POTASH AND PHOSPHORIC ACID REMOVED BY THE FOLLOWING
ROTATIONS FROM A PRUSSIAN MORGEN (.631 ACRE).
Potash. Phosphoric acid.
lb. lb.
1. Wheat 16.40 10.67
Oats 10.47 4.59
Potatoes 66.41 18.33
Hay 39.54 11.32
------ -----
132.82 44.91
------ -----
The ratio of potash to phosphoric acid is 2.96 to 1.
2. Wheat 16.90 10.67
Barley 17.44 10.65
Potatoes 66.41 18.33
Hay 39.54 11.32
------ -----
140.29 50.97
------ -----
The ratio of potash to phosphoric acid is 2.76 to 1.
3. Rye 20.03 12.15
Oats 10.97 4.59
Potatoes 66.41 18.33
Hay 39.54 11.32
------ -----
136.95 46.39
------ -----
The ratio of potash to phosphoric acid is 2.95 to 1.
4. Wheat 16.90 10.67
Oats 10.97 4.59
Mangels 148.54 25.62
Hay 39.54 11.32
------ -----
215.95 52.20
------ -----
The ratio of potash to phosphoric acid is 4.13 to 1.
5. Rye 20.03 12.15
Barley 17.44 10.65
Mangels 148.54 25.62
Hay 39.54 11.32
------ -----
225.55 59.74
The ratio of potash to phosphoric acid is 3.78 to 1.
NOTE XVII. (pp. 253, 254).
COMPOSITION OF FARMYARD MANURE (FRESH), (calculated by SIR
JOHN LAWES).
Phosphoric acid
Total dry Total mineral calculated as Potash. Nitrogen.
matter. matter. phosphate of
lime.
Percent 30.0 2.77 .50 .53 .64
Per ton (in lb.) 67.2 62.0 11.1 12.0 14.3
NOTE XVIII. (p. 232).
THE URINE.
An important consideration we have omitted to take note of in the text
is the quantity of the urine voided. It is this consideration that
renders the urine so much more valuable than the solid excreta. In the
case of a man it has been estimated that the urine voided is fifteen
times as much, is twelve times as rich in nitrogen, three times in
potash, and two in phosphoric acid, as the solid excreta (Munro). The
relation of solid matter in the case of the farm animals is not exactly
similar. The urine of the ox is about twice the weight of its solid
excreta. Both the horse and the sheep, however, void as a rule more
solid excreta than urine. Munro, in his work on 'Soils and Manures,'
contrasts the composition of the urine and solid excreta of the
different farm animals by the following statement:--
1 ton of urine contains 1 ton of solid excreta
in lb.: contains in lb.:
Nitrogen. Potash. Nitrogen.
Cow 30 20 9
Horse 36 22 12
Sheep 38 30 16
FOOTNOTES:
[181] Storer's 'Agricultural Chemistry,' vol. I. p. 496.
[182] Scott's 'Manures and Manuring,' p. 19.