1876 .] 
89 
AMERICAN AGRICULTURIST. 
certain list of substances, viz. : potash, lime, 
magnesia, iron, phosphoric acid, sulphuric acid, 
and some compound of nitrog'en. Besides these, 
chlorine, certainly, and silica, probably, are neces¬ 
sary in many, if not all cases, for the perfec¬ 
tion of the plant. If any one of these substances 
be lacking, the plant will not thrive. AVith an 
abundant supply of all, and other conditions favor¬ 
able, its growth will be luxuriant. 
How has all tills been learned ? 
In the first place, in every analysis that chemists 
make of any plants, be it corn, or grass, or turnips, 
be it iu New England or in Old England—and 
thousands of these analyses have been made—each 
one of these substances has always been found. It 
is fair to suppose, then, that, being always present, 
they have each a work to do in the plant. Still, 
this is not positive proof. As every ordinary soil 
contains all of these substances, is it not possible 
that the plants may take up some of them in the 
water it absorbs from the soil, just as a towel, one 
end of which has fallen into a dish of water, will 
absorb the water and whatever it holds iu solution? 
This question might be tested by growing plants 
in soils with one of these substances absent from 
it, potash for example. But it is difficult to find a 
soil entirely free from potash. It is easy, however, to 
dissolve in pure water any or all of these substances, 
in any desired proportion, and it is well known that 
plants will grow with their roots in water. In view 
of these facts, the German chemist, Knop, some 
years ago conceived the idea of 
Experiments in “Water-Culture.” 
This consists in raising plants without any soil at 
all, but with their roots immersed in water, in 
which are dissolved the soil-ingredients of plant- 
food. Seeds are germinated, or “ sprouted ” in 
pure sand or moist cotton.—At the same time, the 
ingredients of plant-food, which are to be supplied 
to the plants, are dissolved in water in the desired 
proportions, and these solutions put into glass jars. 
At -the tops of these the just germinated plants arc 
placed, properly supported, with their roots dipping 
into the solutions, and thus allowed to grow.... 
Nearly all of the experiments of this class have been 
made by German chemists, prominent among whom 
have been Knop, Sachs, Nobbe, Stohmann, Kuehn, 
and AVolff _Solutions containing all the soil-in¬ 
gredients or plant food are called “ Normal Solu¬ 
tions . ” In these, plants are raised as large, as 
healthy, and in every way as perfect as those grown 
in the soil. Wolff raised in such a solution four 
perfect oat plants with 46 stems, and 1,535 well de¬ 
veloped seeds. Nobbe obtained a Japanese Buck¬ 
wheat plant, 9 feet high, weighing, air-dry, 4,786 
fold the weight of the seed, and bearing 796 ripe, 
and 103 imperfect seeds. Aud Knop used to de¬ 
light in showings his friends a young oak tree, very 
small indeed, but the growth of which had been 
normal, though its roots had been immersed only 
in watery solutions... .The above were obtained 
in the “normal solutions.” AYhat would result if 
one of the necessary food ingredients were omitted ? 
This is answered in 
Hr. Nobile’s Experiment. 
The Engraving with the explanations shows that 
in the normal solution the buckwheat was vigorous 
and healthy, and grew to be nearly 3(4 feet high. 
Another plant (II), grown under precisely the same 
circumstances, except that no potash was supplied, 
led a starving and sickly life, and attained a liight 
of scarcely 3 inches. Without potash no full de¬ 
velopment -was possible. AVhen this was added 
later (in II 3 ), the plant revived, pushed out with 
some vigor, but was unable to overtake its better- 
fed neighbors. Nor did the plants grow well in 
lack of either, lime (IX), or chlorine (X), or nitro¬ 
gen (XI)_These are the results, not of single, 
but of many repeated trials. Dr. Nobbe made in 
this case, a number of different series of experi¬ 
ments, each corresponding to the numbers I, II, 
etc. There were, for instance, several of series I, 
some larger, and others smaller. From these, I 
and la were selected as of average size and develop¬ 
ment. So II, III, etc., were each selected as fair 
average samples of the plants of those series. The 
selected plants were photographed, as shown in 
the picture.Many such series of experiments 
have been carried on with various plants by Nobbe 
and numerous other investigators, and they all 
agree in this 
One General Conclusion: 
No agricultural plant can attain full growth with¬ 
out a sufficient supply through its roots from the 
soil of:' Potash, Lime, Magnesia, Iron, Phosphoric 
Acid , Sulphuric Acid, aud some compound of Nitro¬ 
gen. Besides these, Chlorine, and perhaps Silica, 
are sometimes, if not always, indispensable to 
complete development. If any one of these essen¬ 
tial ingredients be lacking, the plant will suffer in 
growth and development....To settle all these 
points, was not, however, 
THc Heal Object of Hr. Nobbe’s Experiments. 
For this much was well-known before. He de¬ 
sired to go farther and learn what was the use, the 
function, of each essential ingredient in the plant, 
and the form in which it would best do its work. 
In this series he tested potassium, proposing to 
himself three questions. I give the first in his own 
words, translated from the German: 
“Mow will the plant comport itself in a solution 
containing all the ingredients essential to its growth ex¬ 
cept potash, and what will he the explanation of the 
peculiar phenomena that mag he manifested? ” 
Now for the answer. If we examine a green leaf 
with a microscope, we may find in it thousands of 
minute sacs, or cells, as they are called. Some of 
these contain a green substance called chlorophyll, 
(from two Greek words signifying green and leaf), 
which gives the leaf its green color. Inside these 
grains of chlorophyll appear still smaller grains of 
starch. Starch is composed of the elements carbon, 
oxygen, and hydrogen. It is produced inside the 
leaves, which have the power of taking carbon from 
the carbonic acid (a gas consisting of carbon and 
oxygen), in the air, and uniting it with hydrogen 
and oxygen of water to form starch and other 
similar compounds. This is done by aid of chloro¬ 
phyll. After the starch is so formed, it is con¬ 
veyed in the sap to the other parts of the plant, and 
either stored away, as iu potatoes or grain, which 
consist largely of starch, or transformed into woody 
fiber or other materials of the body of the plant. 
And this formation of starch in the chloroplijdl 
grains, and transportation, transformation, and 
storage to build up the plant, is going on contin¬ 
ually as the plant grows. If. then, no starch is 
formed by the chlorophyll in the leaves, growth is 
impossible. 
PotusH Necessary for tlic FonnaiionofStarcii. 
Now in every one of Dr. Nobbe’s plants grown 
without potash, after the starch of the seeds was 
used up, no more appeared in the leaves. As Dr. 
Nobbe says at the conclusion of over a hundred 
pages of description of his experiments, without 
potash the plant “ cannot assimilate (the materials 
needful for its growth), and shows no increase in 
weight, because, without the co-operation of potash 
in the chlorophyll grains, no starch is formed.” 
Dr. Nobbe’s second question was: Of the differ¬ 
ent compounds of potassium, as sulphate, phos¬ 
phate, nitrate, or chloride, which is best adapted 
for the buckwheat plant? In the solutions, the 
chloride proved the best; but there is good rea¬ 
son for believing that in ordinary soils where 
chlorides are present, the other compounds would 
be equally good, and, for many plants, much better. 
The third question was, in substance, 
Cam Any Oilier Element Take tlie Place of 
Potassium. 
The elements sodium and lithium are chemically 
very closely allied to potassium, and it has been a 
question whether these could not perform the 
function of potassium; but in the experiments, 
sodium was totally inefficient, and lithium posi¬ 
tively hurtful. 
THc Results of tlicsc Experiments to be Espe¬ 
cially Remembered, are : 
1st. No agricultural plant can grow without an 
abundant supply, in an available and appropriate 
form, of each of the essential ingredients of plant- 
food. 
2d. Of these, potassium is necessary to the forma¬ 
tion of starch in the clilorophjdl grains of the leaf. 
3d. No other ingredient can fulfill the office of 
potassium in the plant. The same is also known 
to be true of nitrogen, phosphoric acid, and each of 
the other essential ingredients. Each has its own 
work which no other can perform. 
Pracliciil Application of these Principles. 
The Chief Ollice of Fertilizers. 
Crops can no better grow without a sufficient sup¬ 
ply of each of these essential elements in the soil 
than could the plants in the solution. In removing 
crops from our land, we carry away great quanti¬ 
ties of plant food. By continued cropping the 
available supply of one or more of the essential 
ingredients becomes too small for profitable pro¬ 
duction, unless by some means they are replaced. 
The ones most generally deficient are nitrogen, 
phosphoric acid, and potash. The chief use of 
manure is to supply these lacking materials. Stable 
manure is a complete fertilizer, as it furnishes all 
the ingredients of plant food, and improves the 
land besides. Superphosphates, bone-manure, 
guanos, potasli, salts, aud other like artificial fer¬ 
tilizers are valuable chiefly for their nitrogen, phos¬ 
phoric acid, and potash. In their use we should 
first learn what materials the plant needs, and then 
select the fertilizers which furnish these in the 
largest quantity, best form, and at the lowest cost. 
The needs of a given soil can be best learned by 
experience and experiment. The only safe guar¬ 
antee for the composition of commercial fertilizers 
is in chemical analysis. 
Forest Tree Planting-. 
SECOND ARTICLE. 
Last month in advocating the planting of forest 
trees, first, for the profit they would afford if used 
or sold as timber and fuel; and secondly, for the in¬ 
direct profit in sheltering the dwelling, the bams, the 
orchards, and the crops, we omitted to state a third 
source of profit, the fruit or nuts. No doubt a for¬ 
est of chestnuts, hickories, and in favorable locali¬ 
ties the pecan, would pay in the crop of nuts a fine 
rental upon the land, while the value of the timber 
is annually increasing. In advocating the planting 
of forest trees, we are at once met by the question, 
“AVhat shall I plant?” In this article, which in 
the crowded state of our columns must he brief, 
we give a list of the most desirable trees; we do 
not propose to enumerate all that may be planted 
to advantage, but those which will yield the most 
prompt direct and indirect returns. First, as to 
deciduous trees—those which drop their leaves 
in autumn, in distinction from evergreens. If one 
settles in a prairie country, he needs trees which 
will give him shelter and firewood in the quickest 
possible time, and these are soonest afforded by the 
Willows and Poplars.— One advantage of these 
is that they will grow readily from cuttings. How¬ 
ever, the AVliite AA’illow may have been over-praised, 
it is a most valuable tree; in the absence of this its 
yellow variety, the Golden Willow, may he used. 
The same may be said of the poplar, best known as 
Cottonwood ; and the AATiite Poplai*, or Abele, ob¬ 
jectionable in cultivated grounds on account of 
suckers, is also valuable. The willow affords a better 
fuel than the others, and straight poles, which may 
be used as fence rails. A belt of either will pay as 
a wind-break alone, and protect other forest trees 
as well as orchards. The Lombardy Poplar, often 
commended, is liable to be killed by borers by the 
time it gets large enough to be useful. No trees 
will give useful wood and good fuel so quickly as 
The Maples. —Unfortunately, two are cailed 
Soft Maple: Acer ruhrum, and A. dasycargmm; 
to avoid confusion, the name soft should be dropped 
and the trees called Bed and Silver Maples. While 
the last named is a most valuable tree for the 
planter, the other is of little use but for ornament. 
Those who as Soft Maple get the Bed will be dis¬ 
appointed. The Silver Maple ripeus its seed in 
June, and they must be sown then. It has grown 
in seven years from the seed, large enough to make 
three ten feet rails to the tree ; its wood is useful 
for inside work, and the fuel is excellent. Next in 
value is the Ash-leaved Maple, or Box Elder {Negun- 
I do aceroides) ; it naturally spreads widely, but when 
