12 
THE CULTIVATOR. 
These examples will show, that one rule, with respect to the 
laying out of drains, is not appliccble to all cases, but that the 
drainer should adapt bis remedy as much as possible to the cause of 
injury. One object, however, to be aimed at in all cases of under¬ 
draining, is to reach the bed, channel, or reservoir, in which the 
water is contained.__ 
MANURES. 
All substances which, when mixed with the matter of the soil 
tend to fertilize it, are, in common language, termed manures. 
Manures may be composed of animal or vegetable substances; 
or they may consist of mineral matter; or they may be partly de¬ 
rived from mineral and partly from animal and vegeta de substances. 
They may therefore be classed, according to their origin, into— 
1. Animal and vegetable manures, 
2. Mineral manures, 
S. Mixed manures. 
In describing this class of substances, it is not my design to treat 
of their chemical mode of action. This investigation forms one 
of the most interesting parts of the chemistry of agriculture; but 
it is not essential to that practical knowledge of the subject which 
will suffice for the common purposes of the farmer. The remarks 
to be made, therefore, on the mode of action of these bodies, will 
be of a very general nature. 
1st. Animal and vegetable manures .—Chemical analysis shews 
us, that all plants, and all the products of plants, are resolvable 
into a small number of simple bodies, in various states of combi¬ 
nation. These bodies are—carbon, hydrogen, oxygen, and, in 
smaller quantity, nitrogen or azote. These form the essential con¬ 
stituents of all vegetable substances. But there are likewise form¬ 
ed in plants, though in comparatively minute quantity, certain 
other bodies, consisting chiefly of the four earths, silica, alumine, 
lime, and magnesia, of the oxide of iron, and of the alkalies, soda 
and potassa, but chiefly the alkali potassa. 
Now, all these bodies, or the elements of all these bodies, exist 
in animal and vegetable manures; for these being animal and vege¬ 
table substances a r e resolvable into carbon, hydrogen, oxygen, and 
nitrogen, with the intermixed earthy and other bodies, existing in 
the living plants. 
In supplying, therefore, animal and vegetable substances to the 
soil in a decomposing state, we, in truth, supply the same sub¬ 
stances which enter into the composition of the living plants.— 
The substances indeed exist in the dead matter of the manures, in 
states of combination different from those in which they exist in the 
living vegetable; but still they are present, and must be believed 
to supply the matter of nutrition which the plants in growing re¬ 
quire. Science has made known to us the truth, that the living 
plants and the dead manures are resolvable into the same element¬ 
ary substances; but experience has not the less taught the hus¬ 
bandman in every age, that all animal and vegetable substances, 
mixed with the matter of the soil, tended to fertilize it, by affording 
nourishment to the plants which it produced. 
The simple bodies which form the substance of manures exist 
in various states of combination, and often in the solid state. Now, 
there is reason to believe, that, in order that these solid matters 
may be absorbed by the roots of the growing plants, they must be 
dissolved in water. The absorbing pores of the roots of plants are 
so minute, that they are only to be discovered by the microscope. 
The solid bodies, therefore, which find their way into these pores, 
may reasonably be supposed to be held in solution by that aqueous 
matter which enters into the roots of plants, and forms the sap. 
Water is apparently the medium by which all the matter of nutri¬ 
tion, in whatever form, is conveyed into the roots of plants, and 
without which, accordingly, vegetation is never known to take 
place. 
Holding this opinion to be just, the substances which form ve¬ 
getable and animal manures, before they can be rendered available, 
as nutriment to plants, must be rendered soluble in water. 
Of the means which nature employs for this purpose, fermenta¬ 
tion appears to be the chief. By this process, the elementary parts 
of the substance fermented assume new forms of combination, and 
become fitted to supply the matter of nutrition to plants in that 
form in which it can be received, by the pores of the roots. The 
fermentative process is completed after the substance to be used 
as a manure is mixed with the matter of the soil; but it is com¬ 
mon also to cause it to undergo a certain degree of fermentation 
before it is mixed with the earth. This is the method of preparing 
this class of manures for use, which is employed in the practice 
of the farmer. 
Animal matters decompose with facility when acted upon by 
moisture and the air, the greater proportion of their elementary 
parts making their escape in various forms of gaseous combination, 
and leaving the earths, alkalies, and carbonaceous matter, remain¬ 
ing. 
When this decomposition takes place beneath the surface of the 
ground, these gaseous compounds, as well as the carbon, (which 
there is reason to believe assumes also the gaseous state by com¬ 
bining with oxygen,) may be supposed to be partially or wholly 
retained in the earth to afford the matter of nutrition to the plants. 
Purely animal substances, therefore, which thus readily decom¬ 
pose, do not absolutely require fermentation before they are mixed 
with the soil. Yet even in the case of purely animal substances, 
certain beneficial consequences result from subjecting them to a 
previous state of fermentation. Thus the urine of animals, when 
applied in i*s recent state to the soil, is not found to act so benefi¬ 
cially as a manure, as when a certain degree of previous ferment¬ 
ation has been produced. 
And there is another purpose promoted by causing even pure ani¬ 
mal matter to undergo fermentation, and this is, that, being mixed 
with vegetable matter it promotes the more speedy decomposition 
of vegetable fibre. 
Vegetable fibre is, under certain circumstances, a slowly decom¬ 
posing substance. When vegetables are green and full of juices, 
it hey readily ferment; but when the stems are dried, as in the case 
of straw and other litter, they decompose with slowness, and the 
'mixing them with animal matter hastens the putrefactive fermenta¬ 
tion. This mixing of animal with vegetable matter is the process 
employed for preparing the greater part of the dung of the farm¬ 
yard. 
The dung of the farm-yard is the produce of the hay, straw, 
turnips, and other substances used as forage or litter upon the 
farm. It is collected into one or more yards, and fresh litter and 
all other refuse being added to the mass, it gradually accumulates, 
until it is carried out to the fields for use. 
The manner of feeding cattle in their houses and yards will be 
afterwards explained. It is sufficient with relation to the present 
subject, to observe, that the larger cattle may either be fed in 
stalls in close houses, or in yards in which they receive their food. 
When they are fed in close houses, their dung and soiled litter 
are carried to the heap in the yard, where it gradually accumulates, 
and when they are fed in the yards, then dung, in like manner, 
accumulates there, being in the mean time compressed by their 
treading upon it. 
In the practice of the farm, to be afterwards especially described 
as suited to the circumstances of this country, the larger cattle of 
different kinds are brought home to their houses and respective 
yards before winter. Some are kept in their stalls in dose houses, 
and their dung and soiled litter are carried out daily to the yards, 
whilst others receive their food in the yards themselves, and thus 
tread upon the heap. In this manner the mass of dung accumulates 
during the period of feeding, and at the proper period, in the fol¬ 
lowing spring or summer is carried out to the fields and applied to 
the land. 
The dung of the farm-yard is thus sure to be a collection of ani¬ 
mal and vegetable substances. It consists of the excrements of 
the animals kept and fed upon the farm, together with the straw 
or other materials used as litter, and generally of the refuse and 
offal produced about the homestead. This mixed mass is collected 
during the period of feeding, when it undergoes a certain degree of 
fermentation. When trodden by the feet of the animals kept in 
the yards, the effect is to exclude the external air, and to prevent 
the fermentative process from proceeding with that rapidity which 
would take place were the mass not compressed. 
The principal animal substances which are mixed with the ligne¬ 
ous fibres of the litter, and which cause it to undergo decomposi¬ 
tion, are the dung and urine of the animals. 
The properties of this dung, to a certain extent, depend upon the 
kind of animals, and the nature of their food. The dung of horses 
is easily fermented, and is more readily decomposable in proportion 
