142 
THE CULTIVATOR. 
The soil is always exhausted, in a greater or less degree, by the 
plants it produces ; and much more by those that are annual, than 
by those that are perennial. Air and water alone do not afford a 
sufficient degree of nourishment to plants, for when they have been 
made to grow in well washed sand, watered with distilled water, 
though they have flowered, their fruits did not arrive at maturity. 
Experiments to this effect have been made by Messrs. Giobert, 
Hassenfratz, De Saussure, &c. 
Those annual plants which transpire most, generally exhaust 
the soil in the greatest degree. Pease, beans, and buckwheat, 
though they have succulent stalks, exhaust it least, because they 
transpire but little. 
When annual plants are cut at the time of flowering, they do 
not exhaust the soil, as their succulent roots furnish materials for 
replacing the loss occasioned by their growth; but after having 
produced their fruits, the soil derives but little advantage from the 
dry fibres which are the only remains of their stalks and roots. 
During fructification, plants absorb but litle nourishment from 
the soil; the supply necessary to the formation of the seed is fur¬ 
nished by those juices which already exist in the roots and stalks, 
and this occasions them to become dry and exhausted, so that, 
when the fruit is perfected, the roots and stalks consist only of 
woody fibre. It is necessary that this fact should be known, in 
order that too late mowing of meadows, whether natural or artifi¬ 
cial, may be avoided. The most favorable period for cutting 
grass is that of its flowering; if the operation be postponed till 
the seed is formed, two great disadvantages will arise ; the first 
is, that fodder obtained will have parted with the greater portion 
of its nutritive qualities; and the second, that the plants, having- 
fulfilled all the laws of their nature, by providing for their repro¬ 
duction, cannot flourish again with vigor during the same year.* 
In support of this doctrine, I will mention one well known fact, 
which is, that meadows mown before fructification afford the most 
abundant harvests, and the greatest number of them, as they may 
be mown several times in a year. The perennial plants which 
serve as fodder, may by this means be preserved for several years 
in a state of reproduction, but if mown after the formation of seed, 
the plants are weakened and the reproduction is lessened. All 
farmers know, that when they subject to tillage a piece of artifi¬ 
cial grass land, which has for several years been constantly mown 
at the time of flowering, it will yield several harvests without any 
dressing; but if the grass has been left to go to seed, it will be 
necessary to supply the earth with manure before it will yield a 
good return. As those plants that are cut at the time of flowering 
do not exhaust the soil so much as those that remain for seed, the 
belief has arisen amongst farmers, that before the period of fruc¬ 
tification, they are nourished by the constituent principles of the 
surrounding air and water; but that during the time of the forma¬ 
tion of the seed, their support is almost wholly derived from the 
earth. But this opinion will not hold in regard to all plants ; let¬ 
tuce, turnips, tobacco, woad, endive, cabbages, and onions ex¬ 
haust the soil greatly, though they are gathered before producing 
seed. Potatoes, though they produce but few seeds, impoverish 
land more than almost any other vegetable. Plants raised in a 
nursery, and afterwards transplanted, exhaust the soil in which 
they spring, more than the one in which they complete their 
growth. 
Thus we see, that during the whole time of their vegetation, 
plants derive their nourishment from the air, and from the substan¬ 
ces contained in the earth; but if they are mown at the time of 
flowering, they leave in the soil their roots and portions of their 
stalks, which restore to the earth nearly as much as they have 
received from it; whilst, if they remain uncut till they have com¬ 
pleted their course, they return little or nothing to the soil to com¬ 
pensate it for the nourishment they have received from it. 
It is well known to farmers, that ploughing in a green crop of 
any kind whatever, prepares the soil for producing well without 
* Tiiis holds good only in part in regard to timothy (Phleum ptalense.) Ac¬ 
cording to Sinclair, this grass contains more than double the nutriment when 
in seed, than when in bloom. At the same time the remark of Chaptel is cor¬ 
rect, that the root is much more exhausted by maturing its seed, the aftergrowth 
is comparatively trivial, and tho subsequnt crops are diminished. By cutting 
rye in flower, or before, which is either annual or biennial, it may be almost 
rendered perennial, as vve have witnessed, in sowing it with lucern. We 
have observed the same fact in regard to many garden productions—whose 
existence and vigor are prolonged by preventing the formation of the seed— 
Cult. 
any other manure ; since, by this process, all that the soil has yield¬ 
ed is returned to it, with some additions resulting from the decom¬ 
posed principles of air and water, which are contained in the plants. 
In order fully to understand this doctrine, which appears to me of 
great importance to agriculture, it is necessary to consider the 
successive changes which take place in annual plants during their 
growth; first, they produce green leaves, which, by coming in 
contact with the air, receive from it the principles of which I have 
spoken; subsequently the stalks increase in size and number, and 
are covered with numerous leaves, which absorb from the atmo¬ 
sphere a degree of nourishment suited to the increasing wants of 
the plants; the strength, fullness, and depth of hue of the leaves 
and the stalks, particularly of the latter, increase in proportion to 
the richness of the soil. 
This state continues till after the period of flowering, when a 
change, worthy of note, takes place; the roots dry up, the stalks 
wither and change their colour; and when fructification is at length 
completed, both roots and stalks have become mere skeletons, 
which answer but little purpose either for nourishing animals or 
manuring earth. During this period of vegetation what becomes 
of the juices that were so abundant in the roots and stalks ? They 
have been consumed by the formation of the seeds. It is un¬ 
doubtedly the case that plants still continue during fructification to 
absorb some portion of their nourishment from the air and soil; 
and this assists in the formation of their seeds; but by far the 
greatest share of the formation of these is owing to the deposites 
contained in the organs of the plants.* 
The same holds true of perennial plants ; and it may be observ¬ 
ed, that when a tree produces fruit too abundantly it becomes ex¬ 
hausted and dried, and bears only that which is small and misshapen. 
The difference between annual and perennial plants is, that the 
former die as soon as the process of fructification is completed ; 
whilst the latter preserve their leaves green and their roots fresh, 
for the purpose of absorbing new portions of nourishment, to be 
deposited in their vessels for food when the returning warmth of 
spring shall cause them to require it. 
M. Matthieu de Dombasle, one of our most enlightened agricul¬ 
turists, has confirmed by experiments the doctrine I have here ad¬ 
vanced. On the 26th of June, 1820, at the time of flowering, he 
selected, within a small space, forty wheat plants of equal size 
and strength, each having three stalks bearing heads ; he pulled 
twenty of the plants with all their roots, and left the rest to com¬ 
plete their fructification. Having carefully freed from earth the 
roots of those he had taken up, he cut the stalks two inches above 
the base, and dried separately the roots, and the stalks surmounted 
by their heads. 
The roots and the portion of the stalks remaining with them 
weighed, ...grains, 647 
The stalks, heads, and leaves,. “ 1946.5 
Total,. 2603.5 
On the 28th of August, the time of harvesting, he plucked up 
the twenty plants which had been left for seed, separating the 
roots, and cutting the stalks as of the first; of these the weight 
was as follows : 
Roots, ..grains, 419.53 
Straw, husks, and beards,. “ 1318.75 
Grain,. “ 1025.69 
Total,.... 2763.97 
During these two months, the roots and the portions of 
stalks adhering to them had lost,. 237.52 
The stalks, head, and leaves had lost. 624.67 
Total,... 862.19 
But as the seed weighed 1025.69 grains, the whole had increas¬ 
ed in weight 160.57 grains, Troy. From this experiment we may 
conclude, that the juices contained in plants, at the time of flower¬ 
ing, contribute to the formation of the grain, in the proportion of 
T§ll M and that the excess of the weight of the grain which is 
* Thus the succulent stalks of the maize contain, when the grain has at¬ 
tained its growth, die deposites of food necessary to ripen and mature the 
crop, and it supplies this nutriment to the grain, although separated from the 
root, for a considerable time after the grain is put in stooks. And hence 
wheat and rye may be cut before the grain is hard with benefit rather than 
prejudice.— Cult. 
