110 
THE CULTIVATOR. 
useless plants increase, and not those which are beneficial and afford food 
to pasturing animals. Land, when properly laid down to grass, therefore, 
tends to recover its wasted powers of production. Land not properly laid 
down has less of this healing property, and may be more full of weeds, 
and no richer when ploughed up again after a time, than when first laid 
down. Under good management, however, the laying down of cultivated 
land to grass aud other herbage-plants to be consumed upon the ground, 
is a means of resting the soil, and renovating its powers of production; and 
this mode of recruiting an exhausted soil being always at the command of 
the farmer, its application is important in practice. It is to be observed 
also, that the poorer soils require this species of rest and renovation more 
than those which are naturally productive. 
The experience of husbandmen from the earliest times has shown, that 
the same kinds of plants cannot be advantageously cultivated in continued 
succession. The same or similar species tend to grow feebly, or degene¬ 
rate, or become more subject to diseases, when cultivated successively 
upon the same ground ; and hence the rule which forms the basis of a 
system of regular alternation of crops is, that plants of the same or similar 
species shall not be cultivated in immediate succession ; and further, the 
same rule has been thus far extended, that the same species shall recur at 
as distant intervals of the course as circumstances will allow. 
All herbaceous plants whose produce is carried off the ground which 
produces them, may be said to exhaust the soil upon which they grow. 
Hut all such plants do not exhaust the soil in the same degree ; lor after 
some species the soil is seen to be more impoverished than after others. 
And not only do different species of plants exhaust the soil in a greater 
or less degree than others, but the same species does so according to the 
different period of its growth at which the plant is removed from the 
ground. 
When a herbaceous plant is suffered to mature its seeds, it exhausts 
the soil more than when it is removed before its seeds are matured. All 
herbaceous plants, therefore, when cut in their green state, that is, before 
they have matured their seeds, exhaust the soil less than when they re¬ 
main until they have ripened their seeds. Thus the turnip, when used 
in its green state, is one of the least exhausting in the agricultural class of 
plants to which it belongs : but the turnip, when allowed to remain upon 
the ground until it has ripened its seeds, is one of the most exhausting 
plants that is cultivated amongst us ; and so it is with the rape and others. 
Further, certain plants, by the larger or smaller quantity of manure 
which the consumption of them afford, are more or less useful in main¬ 
taining the fertility of the farm. 
When an herbaceous plant is suffered to mature its seeds, and when any 
part of these seeds is carried off the farm, the plant affords, when consum¬ 
ed by animals, a smaller return of manure to the farm than if the same 
plant had been cut down before it had matured its seeds, and been in that 
state consumed by animals. Thus it is with the turnip plant referred to. 
This plant is with us sown before midsummer. In the first season it forms 
a napiform root, and puts forth a large system of leaves. Early in the fol¬ 
lowing season it puts lorth a long stem, which bears flowers, and the seeds 
are generally matured about midsummer. If this plant is removed in the 
first stage of its growth, that is, after it has put forth its large leaves and 
formed its bulb, and is then consumed by animals, it returns a great quan¬ 
tity of manure ; but if it remains until the second state of its growth, then 
the consumption of its stems and leaves returns scarce any manure. The 
juices of the root have apparently been exhausted in affording nutrition to 
the flower-stem, the flowers, and seeds. 
It is beyond a question, that, in order to bring a plant to its entire ma¬ 
turity, by the perfecting of its seeds, a larger quantity of the nutritive 
matter of the soil is sucked up by it than when it is brought only to its less 
advanced stages. When crops of plants, therefore, are suffered to arrive 
at maturity, they are greatly more exhausters of the soil on which they 
grow than when they are cut down while they are green ; and if those 
seeds are in whole or in part carried off the farm, the crops are exhausters 
of the farm, as well as of the ground which had produced them. Were 
the lipened seeds to be wholly returned to the soil, it may be believed 
that they might give back to it all the nutritive matter which had been de¬ 
rived from it. But, in practice, seeds are employed for many purposes, 
and are generally carried off the farm which produces them. When this is 
done in whole or in part, the plants produced are in an eminent de¬ 
gree exhausters of the farm, as well as of the soil on which they have 
grown. 
Further, certain plants, from their mode of growth and cultivation, are 
more favorable to the growth of weeds, than other plants. The cereal 
grasses, from growing closely together, and not admitting, or admitting 
partially, the eradication of weeds, are more favorable to the growth and 
multiplication of weeds than such plants as the turnip and the potato, 
which are grown at a considerable distance from each other, and admit of 
tillage during their growth; and whose broad systems of leaves tend to re¬ 
press the growth of stranger plants. 
Having these principles in view, certain rules may be deduced from 
them, for the order in which the crops of plants in cultivation in a country 
shall succeed to each other on the same ground. 
1st, Crops consisting of plants of the same or similar species, shall not 
follow in succession, but shall return at as distant intervals as the case wiL 
allow. 
2d, Crops consisting of plants whose mode of growth or cultivation 
tends to the production of weeds, shall not follow in succession. 
3d, Crops whose culture admits of the destruction of weeds, shall be 
cultivated when we cultivate plants which favor the production of weeds. 
And further, crops whose consumption returns to the soil a sufficient quan¬ 
tity of manure, shall be cultivated at intervals sufficient to maintain or in¬ 
crease the fertility of the farm. 
And, 4th, when land is to be laid to grass, this shall be done when the 
soil is fertile and clean. 
These rules may be applied to the plants which form the subject of com¬ 
mon cultivation in the fields. In this’country, the plants chiefly cultivated 
on the large scale are,—the cereal grasses, chiefly for the farina of their 
seeds ; certain leguminous plants, as the bean and the pea ; plants culti¬ 
vated for their fibres' as the flax and hemp ; for their leaves, roots, or tu- 
burs, as the turnip, the cabbage, and the potato ; and certain leguminous 
and other plants for forage or herbage. The plants of these different clas¬ 
ses are yet to be described ; and they are now only referred to with rela¬ 
tion to the order in which they may succeed to each other in cultivation. 
The 1st class of these plants consist of the cereal grasses. These are 
chiefly wheat, barley, oats, and partially rye. All these plants are in an 
eminent degree exhausters of the farm. They are all suffered to matuie 
their seeds, and are wholly or partially carried away from the farm. Fur¬ 
ther, from the manner of their growth, and mode of cultivation, they all 
tend to favor the production, of weeds. For these reasons, and on the 
general principle that plants of the same or similar kinds should not follow 
in succession, the cereal grasses should not succeed each other, but should 
be preceded or followed by some crop, which either exhausts the soilless, 
or admits of a more perfect eradication of weeds. 
2d, The leguminous plants cultivated for their seeds, as the bean and 
the pea, are all exhausters of the soil.* They ripen their seeds, and the 
seeds are for the most part carried off the farm. Some physiologist sup¬ 
pose that they are less exhausters of the soil than the cereal grasses. It 
is probable that they do exhaust the soil somewhat less than the cereal 
grasses. But the essential difference between them, when considered 
with relation to their effect upon the soil, is, that, from their growth, and 
the manner of cultivating them, they are greatly less favourable to the 
production of weeds than cereal grasses. By their broader system of 
leaves, they tend to stifle the growth of weeds more than the cereal gras¬ 
ses; and further, they admit of tillage during a great part of their growth. 
This is especially the case with the bean, [and maize] which is therefore 
regarded as a useful cleaning crop, and so is cultivated in rotation with 
the cereal grasses, as a mean of preserving the land clean. 
3d, Hemp and flax, which are cultivated chiefly for their fibres, and all 
plants cultivated for their oils, are exhausters of the soil. They are suf¬ 
fered to form and ripen their seeds, and their stems afford no return of 
manure to the farm. 
The next class of plants, form the large return of manures which the 
consumption of them affords, may be regarded as enriching or restorative 
crops, in contradistinction to the others, which may be termed exhausting 
crops :— 
1. The turnip, the rape, and other plants of the cabbage genus, cultiva¬ 
ted for their roots and leaves, and consumed upon the farm. 
2. The potato, the carrot, the parsnip, the beet, and other plants, culti¬ 
vated for their tubers, and roots, and consumed upon the farm. 
3. The leguminous plants,—the clover, the tare, the lucerne, and others, 
—when cut green for forage, and consumed upon the farm. 
The plants of the latter class, namely the leguminous, when mixed with 
gramineous plants, as the rye-grass, are commonly termed the artificial 
grasses, but would be more correctly termed the cultivated herbage or 
forage plants. They are often suffered partially to ripen their seeds, and 
are made into hay; and in this case they follow the general law, exhaust¬ 
ing the soil more than when used green. And when the hay-crop is car¬ 
ried away from the farm, they are to be regarded as exhausting rather 
than restorative crops. 
In speaking of these different classes of plants, the following terms may 
be employed:—• 
1. The cereal grasses may be termed Corn-crops. 
2. The leguminous plants cultivated for their seeds, Pulse [and maize] 
crops. 
3. The turnip, and other plants of the same kind, cultivated for their 
roots and leaves, may, with reference to the mode of consuming them, be 
termed Green crops; or, with reference to the manner of preparing the 
ground for them, Fallow-crops. 
4. The potato, and plants of other families cultivated for their roots and 
tubers, may, in like manner, be termed Green or Fallow crops. 
5. The leguminous plants cultivated for green food, as the lucerne and 
tare, may be termed Green Forage-crops. 
And, lastly, the mixture of gramineous and leguminous plants cultivat- 
* Indian corn may be included in this class of plants.— Cultivator. 
