Letters on British Agriculture—XL 
. ON DEEPENING THE SOIL. 
Amherst, January 16, 1854. 
L. Tucker, Esq. —When speaking of the Field Cul¬ 
ture of English farmers, I stated that their theory, 
■with regard to deep cultivation, is in advance of their 
practice. By this I meant no reproach to them as a 
class. 
It would be strange, if the leading minds of a great 
industrial interest should not assure themselves well 
of the truth of a theory, before they reduce it to prac¬ 
tice ; and it would be stranger still, if the mass of their 
brethren, in a country where every thing is conserva¬ 
tive, should not be slow to imitate new things , even 
when proved to be beneficial. These considerations 
sufficiently explain the slight diserepancy, of which I 
have spoken, between talk and works. 
But what is the prevailing theory of British farm¬ 
ers, with regard to deep cultivation ? and what proofs 
are there of its soundness! Ought that theory to be 
practiced in that country and in this ? 
1. The prevailing theory of British farmers is, that 
the ground, when no manifest reason for the contrary 
exists, should be loosened, not merely from three to five 
inches, but from thirteen to twenty. Some woffd ad¬ 
vocate trenching with the spade. The effect of this 
would be to mix the upper and lower soil nearly equal¬ 
ly together. If by possibility this course might be ju¬ 
dicious on any of their soils, where produce is dear, 
and where labor is worth but from Is. 6d. to 2s. 6d. a 
day, without board, it would by no means follow that 
it would be wise with us, where labor is dearer and 
produce cheaper. 
Others would advocate trench plowing, to a depth of 
13, 15 or 17 inches, the effect of which would be part¬ 
ly to mix, but mainly to invert the soil. To do this at 
random would be little less than insane. What if the 
subsoil should be so charged with the sulphate or pro¬ 
toxide of iron, or with some other poisonous ingredient, 
that no crop could grow on it for two or three years? 
Or what if the subsoil were so porous, a mere bed of 
gravel, as sometimes (not often) happens, that the sur¬ 
face soil would run away through it? or what if the 
newly exposed earth were too cold for successful cul¬ 
tivation the first year? No man should exchange his 
top soil for a deep subsoil, till he knows well what he 
gives and what he gets. If his top soil be unusually 
exhausted, and he knows by analysis or by a previous 
experiment, on a small scale, that his subsoil is fit for 
the • immediate production of crops, it may then be 
wise to trench plow to almost any depth, but not other¬ 
wise. 
This leads me to remark, that while some British 
farmers would recommend spade-trenching, and others 
trench-plowing, more, and, I think, a better class of 
farmers, would advocate plowing, so as to invert the 
soil from three to eight inches, according to its charac¬ 
ter, say, on ordinary lands, about six inches, and then 
following with a subsoil plow, stirring the soil, but not 
inverting it, to a depth of from 13 to 20 inches from 
the surface. This course has the advantage, 1st, of 
avoiding the danger of bringing up to the surface sub¬ 
stances unfit for promoting the growth of plants ; and, 
2 d, of putting the subsoil into a condition to be warm¬ 
ed, and deprived of hurtful ingredients, so as to be fit 
to be brought up at subsequent plowings. The idea is, 
that we should not bring up the subsoil at random, 
when it may prove less valuable than the soil before 
on the surface, and may very possibly ruin one, two or 
three crops before it becomes fit for use; but should 
first subject it to an ameliorating process, by Ioesening 
it, by giving air and water a free passage through it; 
and then should bring it up by degrees, watching the 
effect, and hastening the process more or less, as we 
see the effect to be favorable or otherwise. 
Farmors in all countries, I suppose to be prudent, 
cautious, thinking men. The very nature of their em¬ 
ployment would make them such. They are not arous¬ 
ed to improvements; but they wish to know whether 
proposed changes are improvements, or whether they 
are mere innovations, before they adopt them. For 
any important change, especially for one involving an 
increased expense of cultivation, they want a reasona¬ 
ble theory, .one which approves itself to their judg¬ 
ment, looks as if it might be beneficial; and then they 
wish it tested by actual experiment. Now is the pre¬ 
vailing theory of British farmers, as I have stated it, 
reasonable ? If you invert the soil to a depth of six 
inches this year and subsoil ten or twelve inches deep¬ 
er ; if then you increase the depth of the plowing an 
inch each year, and repeat the subsoiling once in two 
