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Samuel W. (Samuel William) Johnson.

How crops grow. A treatise on the chemical composition, structure and life of the plant, for students of agriculture. With numerous illustrations and tables of analyses online

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THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

LOS ANGELES



UNIVERSITY of CALIFORNT-

;''l i

LOS ANGELES
LIBRARY



UNIVERSITY of CALIFORNIA

AT

LOS ANGELES
L1BRAJRY




SAMUEL W. JOHNSON, M. A.






HOW CROPS GROW.

A. TREATISE ON THE

CHEMICAL COMPOSITION, STRUCTURE
AND LIFE OF THE PLANT,

FOB STUDENTS OF AGRICULTURE.




2. 2. / 3 -5
BY

SAMUEL W. JOHNSON, M. A.,

PROFESSOR OF THEORETICAL AND AGRICULTURAL CHEMISTRY TS THE SHOT

FIELD SCIENTIFIC SCHOOL OF YALE UNIVERSITY ; DIRECTOR O

THE CONNECTICUT AGRICULTURAL EXPERIMENT STATION;

MEMBER OF THE NATIONAL ACADEMY OF SCIENCES.



StVISED AND ENLARGED EDITiqy.



OEANGE JUDD COMPANY,

1911



Entered, according to Act of Congress, In the year 1890, by the

ORANGE JTJDD COMPANY,
in the Office of the Librarian of Congress, at Washington.



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PREFACE.

The original edition of this work, first published in
1868, was the result of studies undertaken in preparing
instruction in Agricultural Chemistry which the Author
has now been giving for three and thirty years. To-
gether with the companion volume, "How Crops Feed,"
it was intended to present concisely but fully the then
present state of Science regarding the Nutrition of the
higher Plants and the relations of the Atmosphere,
Water, and the Soil, to Agricultural Vegetation. Since
its first appearance, our knowledge of the subject treated
of in the present volume has largely participated in the
remarkable advances which have marked all branehes of
Science during the last twenty years and it has been the
writers' endeavor in this revised edition to post the book
to date as fully as possible without greatly enlarging its
bulk or changing its essential character. In attempting
to reach this result he has been doubly embarassed, first,
by the great and rapidly increasing amount of recent
publications in which the materials for revision must be
sought, and, second, by the fact that official duties have
allowed very insufficient time for a careful and compre-
hensive study of the literature. In conclusion, it is
hoped that while the limits of the book make necessary
the omission of a multitude of interesting details, little
has been overlooked that is of real importance to ;i fajr
presentation of the subjects discussed.
Ill



TABLE OF CONTENTS.

INTRODUCTION 1

DIVISION I. CHEMICAL COMPOSITION OF THE PLANT.

CHAP. I. THE VOLATILE PART OF PLANTS 12

1. Distinctions and Definitions..- 12

2. Elements of the Volatile Part of Plants 14

63. Chemical Affinity 29

$4. Vegetable Organic Compounds or Proximate Elements 36

1. Water 37

2. Carbhydrates 39

3. Vegetable Acids 75

4. Fats S3

. Albuminoids and Ferments 87

6. Amides 114

7. Alkaloids 120

8. Phosphorized Substances 122

CHAP. II. THE ASH OF PLANTS 126

1. Ingredients of the Ash 126

Non-metallic Elements 127

Carbon and its Compounds 128

Sulphur and its Compounds 129

Phosphorus and its Compounds 132

Chlorine and its Compounds 132

Silicon and its Compounds 134

Metallic Elements 138

Potassium and its Compounds 138

Sodium and its Compounds 139

Calcium and its Compounds 139

Magnesium and its Compounds 14*

Iron and its Compounds 141

Manganese and its Compounds 142'

Salts 143

Carbonates 144

Sulphates 146

Phosphates 147

Chlorides 149

Nitrates 149

2. Quantity, Distribution, and Variations of the Ash 151

Table of Proportions of Ash In Vegetable Matter 152

3. Special Composition of the Ash of Agricultural Plants 161

1. Constant Ingredients 161

2. Uniform composition of normal specimens of

given plants 161

Table of Ash-analyses 164

3. Composition of Different parts of Plant 171

4. Like composition of similar plants 173

6. Variability of ash of same species 174

6. What is normal composition of the ash of a plant? 177

7. To what extent is each ash-ingredient essential

or accidental 18C

Water-culture 180

Essential ash-ingredients 186

Is Sodium Essential to Agricultural Plants ? 186

Iron indispensable 192

Manganese unessential 193

Is Chlorine indispensable ? 194

Silica is not essential 197

Ash-ingredients taken up in excess 201

Disposition of superfluous matters 203

State of Ash-ingredients in plant 207

6 4. Functions of the Ash-ingredients 210

CHAP. III. 1. Quantitative Relations among the Ingredients of

Plants 220

52. Composition of the plant in successive stages of

growth 223

Composition and Growth of the Oat Plant 223

T



VI TABLE OF CONTENTS.



DIVISION II. THE STRUCTURE OP THE PLANT AND OFFICES
OF ITS ORGANS.

CHAP. I. GENERALITIES 241

Organism, Organs 242

CHAP. II. PRIMARY ELEMENTS OF ORGANIC STRUCTURE ...243

1. The Vegetable Cell 243

2. Vegetable Tissues 254

CHAP. III. VEGETATIVE ORGANS 256

1. The Root 256

Offices of Root 260

Apparent Search for Food 263

Contact of Roots with Soil 266

Absorption by Root 269

Soil Roots, Water Roots, Air Roots 273

2. The Stem .282

Buds 283

Layers, Tillering 286

Root-stocks '. 287

Tubers 288

Structure of the Stem... 289

Endogenous Plants 290

Exogenous Plants 296

Sieve-cells 303

3. Leaves 306

Leaf Pores 309

Exhalation of Water Vapor 311

Offices of Foliage 314

CHAP. IV. REPRODUCTIVE ORGANS 315

1. The Flower 316

Fertilization 319

Hybridizing 324

Species. Varieties 326

2. Fruit 330

Seed 332

Embryo 333

3. Vitality of -seeds and their influence on the Plants

they produce 335

Duration of Vitality 335

Use of old and unripe seeds 338

Density of seeds 339

Absolute weight of seeds 340

Signs of Excellence 345

Ancestry. Race- vigor 346

DIVISION III. LIFE OF THE PLANT.
CHAP. 1. GERMINATION 349

1. Introductory , 349

2. Phenomena of Germination 350

3. Conditions of Germination 351

Proper Depth of Sowing 355

4. Chemical Physiology of Germination 357

Chemistry of Malt 358

CHAP. II. 1. Food of the Plant when independent of the Seed 366

2. The Juices of the Plant. Their Nature and Movements369

Flow of Sap 370

Composition of Sap 376

Kinds of Sap. 378

Motion of Nutrient Matters 379

3. Causes of Motion of the Juices 385

Porosity of Tissues 385

Imbibition 386

Liquid Diffusion 390

Osmose or Membrane Diffusion 393

Root Action ... 399

Selective Power of Plant 401

4. Mechanical effects of Osmose 406

APPENDIX.
TABLE. Composition of Agricultural Products 409



HOW CROPS GROW.

2.2/33

INTRODUCTION.



The object of agriculture is the production of certain
plants and certain animals which are employed to feed,
clothe and otherwise serve the human race. The first
aim, in all cases, is the production of plants.

Nature has made the most extensive provision for the
spontaneous growth of an immense variety of vegetation ;
but in those climates where civilization most certainly
attains its fullest development, man is obliged to employ
art to provide himself with the kinds and quantities of
vegetable produce which his necessities or luxuries de-
mand. In this defect, or, rather, neglect of nature, ag-
riculture has its origin.

The art of agriculture consists in certain practices and
operations which have gradually grown out of an obser-
vation and imitation of the best efforts of nature, or have
been hit upon accidentally, or, finally, have been deduced
from theory.

The science of agriculture is the rational theory and
systematic exposition of the successful art.

Strictly considered, the art and science of agriculture
are of equal age, and have grown together from the ear-



2 HOW CROPS GROW.

liest times. Those who first cultivated the soil by dig-
ging, planting, manuring and irrigating, had their suffi-
cient reason for every step. In all cases, thought goes
before work, and the intelligent workman always has a
theory upon which his practice is planned. No farm
was ever conducted without physiology, chemistry, and
physics, any more than an aqueduct or a railway was ever
built without mathematics and mechanics. Every suc-
cessful farmer is, to some extent, a scientific man. Let
him throw away the knowledge of facts and the knowl-
edge of principles which constitute his science, and he
has lost the elements of his success. The farmer without
his reasons, his theory, his science, can have no plan;
and these wanting, agriculture would be as complete a
failure with him as it would be with a man of mere
science, destitute of manual, financial and executive skill.

Other qualifications being equal, the more advanced
and complete the theory of which the farmer is the mas-
ter, the more successful must be his farming. The more
he knows, the more he can do. The more deeply, com-
prehensively, and clearly he can think, the more econ-
omically and advantageously can he work.

That there is any opposition or conflict between science
and art, between theory and practice, is a delusive error.
They are, as they ever have been and ever must be, in the
fullest harmony. If they appear to jar or stand in con-
tradiction, it is because we have something false or incom-
plete in what we call our science or our art ; or else we do
not perceive correctly, but are misled by the narrowness
and aberrations of our vision. It is often said of a ma-
chine, that it was good in theory, but failed in practice.
This is as untrue as untrue can be. If a machine has
failed in practice, it is because it was imperfect in theory.
It should be said of such a failure the machine was
good, judged by the best theory known to its inventor,
but its incapacity to work demonstrates that the theory
had a flaw*



ttftBODUCTIOK. 3

But, although art and science are thus inseparable, it
must not be forgotten that their growth is not altogether
parallel. There are facts in art for which science can, as
yet, furnish no adequate explanation. Art, though no
older than science, grew at first more rapidly in vigor
and in stature. Agriculture was practiced hundreds and
thousands of years ago, with a success that does not com-
pare unfavorably with ours. Nearly all the essential
points of modern cultivation were regarded by the Ro-
mans before the Christian era. The annals of the Chi-
nese show that their wonderful skill and knowledge were
in use at a vastly earlier date.

So much of science as can be attained through man's
unaided senses, reached considerable perfection early in
the world's history. But that part of science which re-
lates to things invisible to the unassisted eye, could not
be developed until the telescope and the microscope had
been invented, until the increasing experience of man and
his improved art had created and made cheap the other
inventions by whose aid the mind can penetrate the veil
of nature. Art, guided at first by a very crude and im-
perfectly-developed science, has, within a comparatively
recent period, multiplied those instruments and means of
research whereby science has expanded to her present
proportions.

The progress of agriculture is the joint work of theory
and practice. In many departments great advances have
been made during the last hundred years ; especially is
this true in all that relates to implements and machines,
and to the improvement of domestic animals. It is,
however, in just these departments that an improved
theory has had sway. More recent is the development of
agriculture in its chemical and physiological aspects. In
these directions the present century, or we might almost
say the last fifty years, has seen more accomplished than
all previous time.



4 HOW CROPS GEOW.

The first book in the English language on the subjects
which occupy a good part of the following pages, was
written by a Scotch nobleman, the Earl of Dundonald,
and was published at London in 1795. It is entitled:
"A Treatise showing the Intimate Connection that sub-
sists between Agriculture and Chemistry." The learned
Earl, in his Introduction, remarked that " the slow pro-
gress which agriculture has hitherto made as a science is
to be ascribed to a want of education on the part of the
cultivators of the soil, and the want of knowledge in such
authors as have written on agriculture of the intimate
connection that subsists between the science and that of
chemistry. Indeed, there is no operation or process, not
merely mechanical, that does not depend on chemistry,
which is defined to be a knowledge of the properties of
bodies, and of the effects resulting from their different
combinations. " Earl Dundonald could not fail to see that
chemistry was ere long to open a splendid future for the
ancient art that always had been and always is to be the
prime support of the nations. But when he wrote, how
feeble was the light that chemistry could throw upon the
fundamental questions of agricultural science ! The
chemical nature of atmospheric air was then a discovery
of barely twenty years' standing. The composition of
water had been known but twelve years. The only ac-
count of the composition of plants that Earl Dundonald
could give was the following: "Vegetables consist of
mucilaginous matter, resinous matter, matter analogous
to that of animals, and some proportion of oil. * *
Besides these, vegetables contain earthy matters, formerly
held in solution in the newly-taken-in juices of the
growing vegetable." He further explains by mentioning
on subsequent pages that starch belongs to the mucil-
aginous matters, and that, on analysis by fire, vegetables
yield soluble alkaline salts and insoluble phosphate of
lime. But these salts, he held, were formed in the pro*



INTRODUCTIOH. 5

cess of burning, their lime excepted, and the fact of their
being taken from the soil and constituting the indispen-
sable food of plants, his Lordship was unacquainted with.
The gist of agricultural chemistry with him was, that
plants are " composed of gases with a small proportion of
calcareous matter;" for " although this discovery may
appear to be of small moment to the practical farmer, yet
it is well deserving of his attention and notice, as it
throws great light on the nature and food of vegetables."
The fact being then known that plants absorb carbonic
acid from the air, and employ its carbon in their growth,
the theory was held that fertilizers operate by promoting
the conversion of the organic matter of the soil or of
composts into gases, or into soluble humus, which were
considered to be the food of plants.

The first accurate analysis of a vegetable substance was
not accomplished until fifteen years after the publication
of Dundonald's Treatise, and another like period passed
before the means of rapidly 'multiplying good analyses
had been worked out by Liebig. So late as 1838, the Got-
tingen Academy offered a prize for a satisfactory solution
of the then vexed question whether the ingredients of
ashes are essential to vegetable growth. It is, in fact,
during the last fifty years that agricultural chemistry has
come to rest on sure foundations. Our knowledge of the
structure and physiology of plants is of like recent devel-
opment. What immense practical benefit the farmer has
gathered from this advance of science ! Chemistry has
ascertained what vegetation absolutely demands for its
growth, and points out a multitude of sources whence
the requisite materials for crops can be derived. Cato
and Columella knew indeed that ashes, bones, bird-
dung and green manuring, as well as drainage and aera-
tion of the soil, were good for crops ; but that carbonic
acid, potash, phosphate of lime, and compounds of nitro-
gen are the chief pabulum of vegetation, they did not



HOW CROPS GROW.

know. They did not know that the atmosphere dissolves
the rocks, and converts inert stone into nutritive soil.
These grand principles, understood in many of their de-
tails, are an inestimable boon to agriculture, and intelli-
gent farmers have not been slow to apply them in prac-
tice. The vast trade in phosphatic and Peruvian guano,
and in nitrate of soda ; the great manufactures of oil of
vitriol, of superphosphate of lime, of fish fertilizers ; and
the mining of fossil bones and of potash salts, are indus-
tries largely or entirely based upon and controlled by
chemistry in the service of agriculture.

Every day is now the witness of new advances. The
means of investigation, which, in the hands of the scien-
tific experimenter, have created within the writer's mem-
ory such arts as photography and electro-metallurgy, and
have produced the steam-engine, the telegraph, the tele-
phone and the electric light, are working and shall ever-
more continue to work progress in the art of agriculture.
This improvement will not consist so much in any re-
markable discoveries that shall enable us to "grow two
blades of grass where but one grew before;" but in the
gradual disclosure of the reasons of that which we have
long known, or believed we knew ; in the clear separa-
tion of the true from the seemingly true, and in the ex-
change of a wearying uncertainty for settled and positive
knowledge.

It is the boast of some who affect to glory in the suf-
ficiency of practice and decry theory, that the former is
based upon experience, which is the only safe guide. But
this is a one-sided view of the matter. Theory is also
based upon experience, if it be worth the name. The
fancies of an ignorant and undisciplined mind are not
theory as that term is properly understood. Theory, in
the strict scientific sense, is always a deduction from,
facts, and the best deduction of which the stock of facts
in our possession admits. It is therefore also the inter*



INTKODUCTION. 7

pretation of facts. It is the expression of the ideas which
facts awaken when submitted to a fertile imagination and
well-balanced judgment. A scientific theory is intended
for the nearest possible approach to the truth. Theory
is confessedly imperfect, because our knowledge of facts
is incomplete, our mental insight weak, and our judg-
ment fallible. But the scientific theory which is framed
by the contributions of a multitude of earnest thinkers
and workers, among whom are likely to be the most gifted
intellects and most skillful hands, is, in these days, to a
great extent worthy of the Divine truth in nature, of
which it is the completest human conception and ex-
pression.

Science employs, in effecting its progress, essentially
the same methods that are used by merely practical men.
Its success is commonly more rapid and brilliant, because
its instruments of observation are finer and more skill-
fully handled ; because it experiments more industriously
and variedly, thus commanding a wider and more fruit-
ful experience ; because it usually brings a more culti-
vated imagination and a more disciplined judgment to
bear upon its work. The devotion of a life to discovery
or invention is sure to yield greater results than a desul-
tory application made in the intervals of other absorbing
pursuits. It is then for the interest of the farmer to
avail himself of the labors of the man of science, when
the latter is willing to inform himself in the details of
practice, so as rightly to comprehend the questions which
press for a solution.

Agricultural science, in its widest scope, comprehends
a vast range of subjects. It includes something from
nearly every department of human learning. The natu-
ral sciences of geology, meteorology, mechanics, physics,
chemistry, botany, zoology and physiology, are most in-
timately related to it. It is not less concerned with so-
cial and political economy. In this treatise it will not be



8 HOW CROPS GROW.

attempted to touch, much less cover, all this ground, but
some account will be given of certain subjects whose un-
derstanding will be of the most direct service to the agri-
culturist. The Theory of Agriculture, as founded on
chemical, physical and physiological science, in so far as
it relates to the Chemical Composition, the Structure and
the Life of the Plant, is the topic of this volume.

Some preliminary propositions and definitions may be
serviceable to the reader.

Science deals with Matter and Force.

Matter is that which has weight and bulk.

Force is the cause of changes in matter it is appre-
ciable only by its effects upon matter.

Force resides in and is inseparable from matter.

Force manifests itself in motion and change.

All matter is perpetually animated by force is there-
fore never at rest. What we call rest in matter is simply
motion too fine for our perceptions.

The different kinds of matter known to science have
been resolved into some seventy chemical elements or sim-
ple substances.

The elements of chemistry are forms of matter which
have thus far resisted all attempts at their simplification
or decomposition.

In ordinary life we commonly encounter but twelve
kinds of matter in their elementary state, viz. :

Oxygen, Carbon, Mercury, Tin,

Nitrogen, Iron, Copper, Silver,

Sulphur, Zinc, Lead, Gold.

The numberless other substances with which we arc
familiar, are mostly compounds of the above, or of twelve
other elements, viz. :

Hydrogen, Silicon, Calcium, Manganese,

Phosphorus, Potassium, Magnesium, Chromium,
Chlorine, Sodium, Aluminum, Nickelt



INTRODUCTION.



So far as human agency goes, these chemical elements
are indestructible as to quantity, and not convertible
one into another.

We distinguish various natural manifestations of force
which, acting on or through matter, produce all material
phenomena. In the subjoined scheme the recognized
forces are to some extent classified and defined, in a man-
ner that may prove useful to the reader.



- Repulsive

\ Att ctive

distances I



Act only at
insensible
distances



Attractive



HEA? } Radiant




ELECTRICITY inductive
MAGNETISM j" 3




GRAVITATION Cosmical


Physical


COHESION






CRYSTALLIZATION






ADHESION

SOLUTION


^-Molecular




OSMOSE






AFFINITY


Atomic Chemical


VITALITY Organic Biological



Within human experience the different kinds of force
are mostly convertible each into the others, and must
therefore be regarded as fundamentally one and the same.
Force, like matter, is indestructible. Force acting on
a body may either increase its Kinetic Energy, or be
stored up in it as Potential Energy. Kinetic (or ac-
tual) energy is the energy of a moving body. Potential
(or possible) energy is the energy which a body may be
able to exert because of its state or position. A falling
stone or running clock gives out actual energy. The
stone while being raised, or the clock while winding, ac-
quires and stores potential energy. In a similar manner
kinetic solar energy, reaching the earth as light, heat and
chemical force, not only sets in operation the visible ac-
tivities of plants, but accumulates in them a store of po-
tential energy which, when they serve as food or fuel, re-
appears as kinetic energy in the forms of animal heat,
muscular and uervous activity, or as fire and light.

The sciences that more immediately relate to agricult-
ure we Physics, Chemistry and Biology.



10 HOW CROPS GROW.

Physics, or "natural philosophy," is the science
which considers the general properties of matter and such
phenomena as are not accompanied by essential change
in its obvious qualities. All the forces in the preceding
scheme, save the last two, manifest themselves through
matter without destroying or masking the matter itself.
Iron may be hot, luminous, or magnetic, may fall to the
ground, be melted, welded, and crystallized ; but it re-
mains iron, and is at once recognized as such. The forces
whose play does not disturb the evident characters of sub-
stances are physical.

Chemistry is the science which studies the proper-
ties peculiar to the various kinds of matter, and those
phenomena which are accompanied by a fundamental
change in the matter acted on. Iron rusts, wood burns,
and both lose all the external characters that serve for
their identification. They are, in fact, converted into
other substances. Chemical attraction, affinity, or chem-
ism, as it is variously termed, unites two or more ele-
ments into compounds, unites compounds together into
more complex compounds ; and, under the influence of
heat, light, and other agencies, is annulled or overcome,
so that compounds resolve themselves into simpler com-
binations or into their elements. Chemistry is the science
of composition and decomposition ; it considers the laws
and results of affinity.

Biology, or physiology, unfolds the laws of the
propagation, development, sustenance, and death of liv-
ing organisms, both plants and animals.

When we assert that the object of agriculture is to de-



Online LibrarySamuel W. (Samuel William) JohnsonHow crops grow. A treatise on the chemical composition, structure and life of the plant, for students of agriculture. With numerous illustrations and tables of analyses → online text (page 1 of 34)