HOW SHALL THE SOIL BE IMPROVED? 
145 
HOW SHALL THE SOIL BE IMPROVED ? 
In considering the important question, how 
shall the deterioration of the soil be most readily- 
prevented and its fertility increased, I have been 
not a little perplexed with the different views en¬ 
tertained, and the different directions given by the 
savans [ 1 ] in agricultural science. 
For instance, a few years ago, great value was 
attributed to nitrogen , as it exists in manure, Lie¬ 
big, in his “ Organic Chemistry,'” asserts that there 
are “ numerous facts, showing, that the formation in 
plants of substances containing nitrogen, such as 
gluten, takes place in proportion to the quantity of 
this element which is conveyed to their roots in the 
state of ammonia, derived from the putrefaction of 
animal matter?' 1 And again, speaking of the great 
importance of the nitrogenous principle in manure, 
the same author says—“ Animal manure acts only 
by the formation of ammonia.’ 7 
To prove this, he cites an instance where a soil 
manured with cow dung, which contains but a small 
quantity of nitrogen, produced wheat of which one 
hundred parts afforded only 1V95 parts of gluten, 
and 64*34 parts of starch 5 whilst the same quantity 
of wheat grown on a soil manured with human 
urine, which contains a large proportion of nitro¬ 
gen, yielded 35-1 per cent, of gluten. 
Liebig, however, held that ammonia was not only 
evolved by animal bodies, but that it also “ existed 
before the creation of human beings, as a part, a 
primary constituent, of the globe itself, 7 ’ He de¬ 
tected the substance in rain water and snow water, 
and thence deduced that it was brought to the earth 
by the descent of vapor in those forms. He be¬ 
lieved that charcoal, decaying wood, humus , or 
vegetable mould, possessed the property of attract¬ 
ing or absorbing the ammonia of the atmosphere, 
and that by the application of these matters to the j 
soil, they became a means of supplying plants with 
their necessary nitrogen. Charcoal, he stated, was 
capable of absorbing “ ninety times its volume of 
ammoniacal gas, and decayed oak wood seventy- 
two times its volume.” 
These views became very extensively dissemi¬ 
nated and adopted. Their announcement in this 
country, together with other theories of the great 
German chemist, created no little excitement, and; 
some were very enthusiastic in their advocacy of 
the new doctrine. To secure ammonia and render 
it subservient to the uses of plants, seemed to be the 
great idea and object. Various were the “traps 7 ’ 
devised for taking and holding this volatile sub¬ 
stance. The papers teemed with directions for 
making 11 steeps 77 of ammonia and nitre for seeds, &c. . 
One individual, somewhat distinguished, of late 
years for his zeal in the- cause of agricultural im- 
rovement, and who, to use his own language, 
ad, as “ a practical agriculturist, devoted the best, 
energies of his mind for years to the study of ag¬ 
ricultural chemistry, vegetable and animal physiol- i 
ogy,” strongly recommended common charcoal as; 
“ the cheapest and therefore the best material to i 
apply to cultivated fields’ 7 for the purpose of fixing 
ammonia. He stated that “ the liberal application . 
of this well-known substance (charcoal) to the 
wheat fields of France, had mainly, in connexion 
with lime, added within the last ten years (from 
IS33 to 1843), 100,000.000 bushels to the annual 
crop of wheat grown in that kingdom .’ 7 He pro¬ 
ceeded to say, in the same connexion, that he con¬ 
sidered the subject “ of vast practical importance 
and adds, “ by studying -the science of agriculture, 
you may grow fifty bushels of good wheat on any 
acre of your land, * * * bating, of course, extreme 
casualties.” It is evident that a knowledge of the 
use of charcoal, or of its application for the purpose 
above described, was considered an important part 
of the •'•‘ science of agriculture,” from which such 
“ vast ’ 7 benefits were expected. 
But within the lapse of only a few years, men, or 
their theories, have greatly changed. Liebig now 
holds that the ammonia of manures is of no “ mo¬ 
ment”—that plants derive an abundant supply of 
that element, as he supposes they do of carbon also, 
from the atmosphere ! He holds that the organic 
part of manures, including the ammonia, is not ne¬ 
cessary in supplyiijg/botf to plants—that vegetable 
matters only operate mechanically on the soil. In. 
accordance with the basis of this theory, it has been 
argued that we might as well burn manures and 
apply the ashes only to crops! 
In the London “Farmers’ Magazine,” for De¬ 
cember last, there is a translation of part of a letter 
which was addressed by Liebig to the editor of the 
“Revue Scientifique et Industrielle,” in which he 
(Liebig) states that he had formerly regarded 
“ azote as not only useful but also necessary, 7 ’ 
but that the results of experiments and observation 
have induced him to alter his opinion. In refer¬ 
ence to his present views he says—“ It has been 
demonstrated that ammonia is a constituent part of 
the atmosphere, and that as such, it is directly ac¬ 
cessible and absorbable by all plants. If, then, the 
other constituents necessary to the growth of plants 
be satisfied—if the soil be suitable, if it contain a 
sufficient quantity of alkalies, phosphates, and sul¬ 
phates, nothing will be wanting ; the plants will de¬ 
rive their ammonia from the atmosphere , as they do 
carbonic acid. We know that they are endowed 
with the power of assimilating these two elements ; 
and I really cannot’see why we should search for them 
in the manures we use. 77 
This theory seems to have obtained considerable 
credence in this country, and singular as it may 
seem, some of its most strenuous advocates are among 
those who but a short time since attributed such 
wonderful virtues to ammonia. But with them, 
charcoal and ammonia have had their day, and are no 
longer reckoned among the things needful to sustain 
the fertility of the soil, (a) Even the individual from 
whose remarks in recommendation of charcoal an 
extract is given above, has lately declared, in an 
article on the “ Theory of Agriculture,” that if the 
farmer will only “ restore all the earthy part of 
each harvest to the field whence it was taken, he 
may grow any crop, year after year, * * * without 
injury to the soil.” ! ! 
This announcement would naturally be received 
with some surprise by farmers who had been accus¬ 
tomed to the ordinary course of manuring ; but 
when it is known to proceed from one who only a 
a short time since was so earnest in the recommenda¬ 
tion of charcoal and ammonia, it appears startling! 
I have nothing to say in regard to the opposite 
character and inconsistency of the theories above- 
mentioned ; but in regard to sustaining or restoring 
