74 
THE CULTIVATOR. 
face. “ It is worthy of observation, that the ammonia 
contained in rain and snow water, possesses an offen¬ 
sive smell of perspiration and animal excrements—a 
fact which leaves no doubt respecting its origin.” 
Prof. Liebig’s volume contains a great number of in¬ 
teresting details on the presence of ammonia in plants, 
thus proving that it is actually taken up by the roots, 
and in that form applied by their organs to the produc¬ 
tion of the azotized matters contained in them. Thus 
ammonia was obtained from maple sugar, the juice of 
the birch, the juice of the beet, the products of the 
distillation of flowers, herbs and roots, and the unripe 
gelatinous pulp of the peach and almond, contain it 
in quantities easily appreciable. In short there is scarce 
a vegetable tissue of any kind free from it. 
“Animal manure,” says Prof. Liebig, “as we shall after¬ 
wards show, acts only by the formation of ammonia. One 
hundred parts of wheat, grown on a soil manured with cow- 
dung, (a manure containing the smallest quantity of nitrogen,) 
aiforded only 11-95 parts of gluten, and 64-34 parts of amylin, 
or starch; while the same quantity, grown on a soil manured 
with human urine, yielded the maximum of gluten, namely, 
35-1 per cent. * * * The barren soil on the coast of Peru 
is rendered fertile by means of a manure called guano,. which 
is collected from several islands in the South Sea. It is suffi¬ 
cient to add a small quantity of guano to a soil which consists 
only of sand and clay, in order to procure the richest crop of 
maize. The soil itself does not contain the smallest particle 
of organic matter, and the manure employed is formed only of 
urate , phosphate, oxalate , and carbonate of ammonia, together 
with a few earthy salts.” 
The importance of nitrogen to plants intended for 
the support of animal life, may be inferred from the 
fact, 
“That the quantity of food, which animals take for their 
nourishment, diminishes or increases in the same proportion 
as it contains more or less of the substances containing nitro¬ 
gen. A horse may be kept alive by feeding it with potatoes, 
which contain a very small quantity of nitrogen; but life thus 
supported is a gradual starvation; the animal increases neither 
in size nor strength, and sinks under every exertion. The 
quantity of rice which an Indian eats astonishes the European; 
but the fact that rice contains less nitrogen than any other 
grain, at once explains the circumstance.” 
In practice then, that farmer will be the most suc¬ 
cessful who manages his manures, or the source erf 
ammonia, in such away that they will serve as a nutri¬ 
ment to his own crops. A heap of manure lying on 
the surface of a farm benefits the owner no more than 
it does his neighbors. The nitrogen escapes as carbo¬ 
nates of ammonia into the atmosphere, and the carbo¬ 
naceous matter or decayed vegetable part is soon all 
that is left in its place. 
Prof. Liebig’s discovery of ammonia in water, has 
led to a simple yet beautiful explanation of the manner 
in which gypsum acts on plants. We gave some notice 
of this in the March No. of the Cultivator. Prof. L. 
says : 
“ The carbonate of ammonia contained in rain water, is de¬ 
composed by gypsum in precisely the same manner as in the 
manufacture of sal ammoniac. Soluble sulphate of ammonia 
and carbonate of lime are formed, and this salt of ammonia, 
possessing no volatility, is consequently retained in the soil. 
All the gypsum gradually disappears, but its action upon the 
carbonate of ammonia continues as long as a trace of it exists. 
* * * The action of gypsum or chloride of calcium really 
consists in their giving a fixed condition to the nitrogen or 
ammonia which is brought into the soil, and which is indispen¬ 
sable to the nutrition of plants.” 
The substances named above as carbonic acid, water, 
and ammonia, are necessary to the existence of plants, 
as they contain the elements from which plants are 
formed ; but there are other substances requisite for 
the formation of certain organs or parts destined for 
special functions. Plants obtain these substances from 
inorganic nature ; and although in a changed form, the 
ashes left by incineration contain the salts and earths 
which are thus useful. There are numerous metallic 
oxid.es and phosphates, and alkaline bases, which are 
thus employed, and on the quantities of these contain¬ 
ed in my given soil, the character of its vegetation will 
depend. 
“All kinds of grasses contain in the outer part of their leaves 
and stalks a large quantity of silicic acid and potash in the form 
of silicate of potash. The proportion of this salt does not vary 
perceptible in corn [grain] fields because it is conveyed to 
them again in the form of putrefying straw. But this is not 
the case in a meadow, and hence we never find a luxuriant 
crop of grass on sandy or calcareous soils which contain little 
potash, evidently because one of the constituents indispensable 
to the growth of the plants is wanting. Soils formed from ba¬ 
salt, graywacke, and porphyry are, carter is paribus, the best 
for meadow lantf, on account of the quantity of potash which 
enters into their composition.” 
Without alkalies or alkaline bases most plants could 
not exist, and the roots of plants are constantly engag- 
ed in collecting from the rain, those alkalies which 
have been raised by vaporization from the sea ; which 
according to Prof. Liebig, is the grand reservoir of these 
substances, and from which they are distributed over 
the earth by winds and clouds. According to Marcet, 
sea water contains chloride of sodium, sulphate of 
soda, chloride of potassium, chloride of magnesia, sul¬ 
phate of lime, carbonic acid in a proportion 100 times 
greater than that of the air, and ammonia ; so that 
the same conditions which sustain living bodies on the 
land are combined in this medium, in which a whole 
world of other plants and other animals exist.’ 
It is well known to the farmer, that when gypsum 
first came into general use, after a few years had passed, 
the substance was severely condemned as an exhauster 
of the soil, an opinion now exploded, and which finds 
no advocates among the intelligent, the exhaustion com¬ 
plained of arising not from the increased crops, but a 
defective culture. On this point, Prof. Liebig has the 
following just remarks: 
“But when we inerease the crop of grass in a meadow by 
means of gypsum, we remove a greater quantity of potash with 
the hay, than can, under ordinary circumstances be restored. 
Hence it happens, that after the lapse of several years the 
crop of grass on the meadows manured with gypsum diminish, 
owing to the deficiency of potash. But if the meadow be strew¬ 
ed from time to time with wood ashes_, even with the lixiviated 
ones which have been used by soapboilers, (in Germany much 
soap is made from the ashes of wood,) then the grass thrives 
as luxuriantly as before. The ashes are only the means of re¬ 
storing the potash.” 
A fine illustration this, of the cause which render 
leached ashes so valuable as a manure on the sandy soils 
of Long-Island or New-Jersey. The addition of the 
alkali gives rise lo the formation of silicates of potash, 
without which the stems of the grasses, or the cereal 
plants cannot be formed. 
The growth and development of plants is, therefore, 
depending on the presence of alkaline earths, or alka¬ 
lies ; and the growth will be rapid, and the develop¬ 
ment perfect in proportion to the existence of the pro¬ 
per quantity. Hence too plants, which require but a 
small quantity of these substances, will grow and flour¬ 
ish where other plants would perish. Every one is 
aware, that firs and pines will grow on barren granite 
or sandy soils, and find potash enough for their use, 
while oaks will not flourish on such soils. The exami¬ 
nation of 10,000 parts of oak wood yield 350 parts of 
ashes, the same quantity of fir wood only 83 parts. 
The numerous instances given by Liebig, of the im¬ 
portance of these alkaline metallic oxides on vegeta¬ 
tion, show beyond controversy, that their influence has 
been too much overlooked. It has been thought remar¬ 
kable by some vegetable physiologists, that those cereal 
grasses which furnish food for man, should as it were, 
follow him wherever he goes. The reason is to be 
found in the fact, that none of our grain plants can 
produce perfect seeds, or seeds yielding farina, with¬ 
out a greater supply of phosphate of magnesia and am¬ 
monia, than can be found in regions where these salts, 
resulting from organized vitality, are less abundant. It 
follows that wherever men abound, these plants find 
their proper food and follow in their train, with the cer¬ 
tainty and regularity of the domesticated animals. 
The part of Prof. Liebig’s volume, devoted to the 
art of culture, is well worthy the study of the farmer. 
After a description of the constituents of soils, and the 
manner of their formation, he goes on to describe the 
effects of constant culture, where no ameliorating 
means are used. Prof. L. says : 
“The first colonists of Virginia found a country the soil of 
which was similar to that mentioned above; [rich in alkalies 
and humus,] harvests of wheat and tobacco were obtained for 
a century from one and the same field without the aid of ma¬ 
nures, but now whole districts are converted into unfruitful 
pasture land, which, without manure, produces neither wheat 
nor tobacco. From every acre of this land there were removed 
in the space of 100 years 1,200 pounds of alkalies in leaves, 
grain, and straw ; and it became unfruitful because it was de¬ 
prived of every particle of alkali, which had been reduced to 
a soluble state, and because that which was. rendered soluble 
again in the space of one year, was not sufficient to satisfy the 
demands of the plants. Almost all the cultivated land in Eu¬ 
rope, is in this condition; fallow is the term applied to land 
left at rest for further disintegration. It is the greatest possi¬ 
ble mistake to suppose that the temporary diminution of fer¬ 
tility in a soil is owing to a loss of humus; it is the mere 
consequence of the exhaustion of the alkalies.” 
This view receives a .strong confirmation from the 
culture and crops on the lava soils around Vesuvius, 
and where after a cropping of more than a thousand 
years, without any manure being applied, grain crops 
are still produced with undiminished profusion. This 
decomposed lava, though containing little humus, is 
rich in alkalies, and this accounts for the prodigious fer¬ 
tility of the mass. Every farmer is aware that those 
parts of his fields where black muck, or nearly pure 
vegetable mold, is in the greatest abundance, usually 
if not always give the most inferior grain. The straw 
may be large, but it will want firmness, and the berry 
will be shrunken and imperfect. “ The cause is this, 
—that the strength of the stalk is due to silicate of pot¬ 
ash, and that the grain requires phosphate of magnesia, 
neither of which substances a soil of humus can afford, 
since it does not contain them; the plant may indeed 
become an herb, but will not perfect its fruit or seed.” 
It has been ascertained that 100 parts of wheat stalks 
yield 15.5 parts of ashes ; the same quantity of barley 
stalks 8.54 ; and oats only 4.42 of ashes, which are all 
of the same composition. It would appear from these 
facts that upon the same field which will yield only one 
harvest of wheat, two crops of barley, and three of oats 
may be raised. There are some plants, such as the 
leguminosce, (peas, beans, See.,) and buckwheat, which 
are remarkable for the small quantity of alkalies they 
contain, and the first named plant, it is well-known, is 
successfully used in a rotation of crops, as one which 
may precede wheat advantageously. 
Prof. Liebig is a strenuous advocate for a rotation of 
crops, and his reasons are based on the theory of De- 
candolle, which he considers as fully established : 
“Decanclolle supposes that the roots of plants imbibe soluble 
matter of every kind from the soil, and thus necessarily absorb 
a number of substances which are not adapted to the purposes 
of nutrition, and must subsequently be returned to the soil as 
excrements. Now, as excrements cannot be assimilated by 
the plant which rejected them, the more of these matters which 
the soil contains, the more unfertile must it be for plants of the 
same species. These excrementitious matters may, however, 
still be capable of assimilation by another kind of plants, which 
would thus remove them from the soil, and render it again fer¬ 
tile for the first. And if the plants last grown also expel sub¬ 
stances from their roots, which can be appropriated as food by 
the former, they will improve the soil in two ways.” 
Macaire Princep established this latter fact, and 
proved that as some plants assimilate the rejected mat¬ 
ter of others, a rotation of crops, founded on the facts 
so demonstrated, could not be otherwise than beneficial. 
On this subject, no well informed farmer has now any 
doubt, and the rotation of roots, grains and grasses has 
become part of every well arranged system. The ex¬ 
periments of these distinguished men have been verified 
by others, but for their history we must refer to Prof. 
Liebig’s work itself. This excrementitious matter in 
time undergoes a change into a substance like humus, 
or which supplies its place, as a source of carbonic acid. 
The time to effect this change depends on the composi¬ 
tion of the soil, and on its greater or less porosity. It 
is the quickest on a calcare.ous soil, for the power of 
organic excrements to attract oxygen and to purify, is 
alway increased by alkaline constituents ; the change is 
slowest on heavy soils, such as wet loam, or clay. 
No fact is better ascertained than that the fertility of 
a soil cannot remain unimpaired, unless those substan¬ 
ces, of which it from time to time is deprived by cropping, 
are replaced, and this is effected by manure. It is on 
this point that Prof. Liebig’s work is invaluble. The 
substances that in plants go to form food for animals, 
and form flesh by assimilation, are here traced to their 
original elements ; and the substances which in the ex¬ 
crements of the cow and horse exert an influence on ve¬ 
getation are pointed out, and the extent of that influ¬ 
ence estimated. A careful analysis of manures proves 
there are other substances which will answer the same 
purpose as animal manures, of which one of the most 
prominent is ashes, lixiviated or otherwise, and which 
contain a large portion of phosphates. 
“With every 100 pounds of the lixiviated ashes of the beech 
which we spread over a soil, we furnish as much phosphates 
as 460 pounds of fresh human excrements would yield. Again, 
according to the analysis of De Saussure, 100 parts of the ashes 
of the grain of wheat contain 32 parts of soluble, and 44-5 of 
insoluble phosphates, in all 76-5 parts. Now the ashes of 
wheat straw contain 11-5 per cent of the same salts; hence 
with every 100 pounds of the ashes of the beech, we supply a 
field with phosphoric acid sufficient for the production of 3,820 
pounds of straw, the ashes being calculated at 4-3 per cent; 
or for 15-18,000 pounds of grain, the ashes of which amount, 
according to De Saussure, to 1 - 3 per cent.” 
Bone manure is still more powerful from this cause. 
The bones of animals are derived from the hay, straw, 
&c. which they take as food. Bones contain 55 per 
cent of the phosphates of lime and magnesia, and hay 
contains about as much of them as. wheat straw, conse¬ 
quently eight pounds of bones contain as much phos¬ 
phate of lime as 1,000 pounds of hay or wheat straw, 
and two pounds of it as much as 1,000 pounds of the 
grain of wheat or oats. The quantity of manure sup¬ 
plied to land with forty pounds of bone dust, is suffi¬ 
cient to furnish three crops of wheat, clover, potatoes, 
or turneps, with phosphates. Prof. Liebig’s work on 
this point strikingly illustrates the effect which a small 
quantity of these salts will produce on a soil. It is a 
matter of indifference in what form the substances ta¬ 
ken from a soil are restored to it, whether in excre¬ 
ments, ashes or bones, the effect is much the same. Prof. 
Liebig, indeed, says : 
“A time will come when fields will be manured with a solu¬ 
tion of glass, (silicate of potash,) with the ashes of burnt 
straw, and with salts of phosphoric acid, prepared in chemi¬ 
cal manufactories, exactly as at present medicines are given 
for fever and goitre.” 
Prof. Liebig shows that excrements, or dung, have a 
very variable and relative value. Their power is main¬ 
ly owing to the nitrogen or ammoniacal salts they pro¬ 
duce or contain, and in common dung this quantity is 
very minute. The nitrogen contained in the fasces of 
man is greater than in that of animals, but is by no 
means constant. In that of the inhabitants of towns 
the amount is greater of this constituent, than in that 
of those in the country ; as in cities more animal mat¬ 
ter is used. “ The faeces of those who live principally 
on bread and potatoes are similar in composition and 
properties to those of animals.” 
The manure from cattle and horses are mostvaluable 
on soils consisting of lime and sand, as such are usual¬ 
ly deficient in silicates and phosphates ; while their ef¬ 
fect is less on soils that are argillaceous or granitic, as 
these usually contain all the potash that is necessary, 
or at least a considerable quantity. In such soils, hu¬ 
man excrements increase the fertility in a remarkable 
degree, and it is here that poudrette exercises an almost 
magical influence. The urine of man and animals con¬ 
tains in its nitrogen a source of the greatest fertility, as 
from it ammoniacal salts are formed in abundance. 
The active properties of urine exist in its urea, tree 
lactic acid, and lactate of ammonia. When urine pu¬ 
trefies. or becomes available to vegetation, the urea is 
converted into lactate of ammonia, or volatile carbonate 
of ammonia, one of the most powerful of the fertilizing 
agents. 
The great obstacle in the use of urine as a fertilizer 
has arisen from the escape of the ammonia, but accord¬ 
ing to Prof. Liebig, it may be fixed and retained for the 
use of plants xvithout difficulty. 
“If a field be strewed with gypsum and then with petrified 
urine, or the drainings of dung-hills, all the carbonate of am¬ 
monia will be converted into the sulphate, which will remain 
in the soil. But there are still simpler means of effecting this 
purpose: gypsum, chloride of calcium, sulphuric or muriatic 
acid, and superphosphate of lime, are all substances of very 
low price, and completely neutralize the urine, converting its 
ammonia into salts, which possess no volatility. * * * If 
we strew the floors of our stables with gypsum from time to 
time, they will lose all their offensive smell, and none of the 
ammonia which forms can he lost, but will be retained in a 
condition serviceable as manure.” 
Pastures act a most important part in returning to the 
soil a supply of nitrogen in place of that taken away in 
