CORNELL READING-COURSE NO. I
Issued by the College of Agriculture, Cornell University, NOVEMBER, 1902.
Ithaca, N. Y, in the months of November. December.
January, February and March under Chapter 430 of the 4TH EDITION.
Laws of 1899.
Entered at the Post Offce, at Ithaca, N. Y.. as second-class BY L. H. BAILEY.
The Soil: What It Is.
I. The basis of soil is fragments of rock.-As the earth cooled,
the surface solidified into rock. The processes of nature have
been constantly at work in breaking up this rock and making it
2. Weathering is the great agency in making rocks into soil.-
Rain, snow, ice, frost have worn away the mountains and
deposited the fragments as soil. Probably as much material
has been worn away from the Alps as still remains, and this
material now forms much of the soil of Italy, Germany, France,
Holland. Our own mountains and hills have worn away in like
3. Weathering is still active.-All exposed rocks are wearing
away. Stones are growing.smaller. The soil is pulverized by
4. The particles of soil are worn and transported by water.-
Every stream carries away great quantities of soil and deposits
it in the shallows and the bays. After every rain, the streams
and ponds are muddy or roily. Observe the sediment or fine
mud which remains when a "mud puddle" dries up. The
smallest rivulet carries away tons of earth every year; and this
earth is deposited somewhere, and sometime it may, perhaps,
come into use again for the growing of plants. Many of our
best and richest farm lands are the deposits of former streams
and lakes. Such lands are fine and silt-like. Most lowlands
belong to this category; and even some of our higher lands are
formed from deposits from water. The mixed and varied char-
acter of soils is largely due to the fact that they are the results
of transportationlfrom different places.
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Observe the flat lands about lakes. These flats are formed by
the deposition of material from the surrounding highlands ; but
they are often'exposed before their natural time by the lowering
of the water level in the lake. All lakes and ponds are filling up.
Nearly every stream makes a delta at its mouth; but if the stream
into which it empties is swift, the delta may be carried away.
Observe also, the broad rounded hillocks and knolls in valleys
and ravines. Many of them have attained their present form
from the action of moving water.
Every farmer knows that overflowed lands are rich. He has
heard of the wonderful fertility of the Nile. He should explain
5. All productive soils also contain organic matter.-Organic
matter is the remains of plants and animals. As found in soils
in a decaying condition, it is called humus. It is the humus
which gives the soil its dark or "rich" look. It also tends to make
soils loose, warm and mellow. It holds moisture. The addition
of humus makes soils loamy. A sandy loam is a soil of which
the original mineral matter is sand, and a clayey loam is one of
which the basis is clay. Soils which have no humus are hard,
" dead"' and unproductive.
6. Humus is supplied by means of roots and stubble, green-crops
and barn manures.-If the farmer practices a rotation of which
meadow and- pasture are a part, the supply of humus will be
maintained. In such cases green-manuring is unnecessary
except now and then upon lands which are very hard or poor.
The roots and stubble, with the droppings of the animals on the
pasture, and manure applied with one of the crops in the rota-
tion, keep the land well supplied with vegetable matter. When-
ever possible, it is better to feed the crop to stock and return the
manure to the land, than to plow the crop under; for one will
get back the greater part of the fertilizing value of the crops and
maintain the animal at the same time. In western New York
there are hundreds of acres of refuse lands, and at this day there
are thousands of tons of herbage on the ground, and no stock to
eat it. It is wasteful.
Many soils which are said to be worn out are robbed of their
humus rather than of their plant-food ; others have been injured
in their texture by careless or faulty management: In supplying
humus, it is better to add small quantities often. Lands which are
under constant tillage, in corn, wheat, oats, potatoes, may be
supplied with humus if catch crops are sown with the crop, now
and then, late in the season. Rye, Canada peas, crimson clover,
and the like may be used for this purpose. Plow them under as
soon as the land is ready in the spring, even if the plants are
Observe how the forest supplies its humus. Year by year the
leaves add to the soil cover, slowly passing into vegetable mold
or humus. The trunks finally decay and pass into the soil.
The work is effectively done, but it consumes times; and man is
in a hurry. When the forest is removed the land is very pro-
ductive. It is called "virgin soil" notwithstanding the fact
that an enormous crop of trees has just been taken from it, and
that it may have grown hundreds of such crops. The real vir-
gin soil is the barren soil. But however rich this forest soil may
be when the timber is first removed, it generally soon loses its
exuberant fertility. The pigmy crops of the farmer seem to be
harder on the soil than the gigantic crops of Nature. Some of
this loss of productivity is due to the loss of humus.
A rotation prevents the exhaustion of plant-food, supplies
nitrogen in leguminous crops, one crop leaves the land in better
condition for another, the roots and stubble improve the texture
of the soil, it keeps weeds in check, provides for continuous labor
because stock is kept.
The rotation should differ with the kind of soil and general
style of farming. The Cornell rotation is:
Clover and timothy, i year,
A good rotation for weed-infested land is:
Sod, i year,
Potatoes, or some other tilled crop,
Oats or barley.
On fruit farms, rotations are not so practicable as on grain
farms; but the fields which are not in fruit can often be worked
in rotation to great advantage. The general tendency of fruit-
farmers is to keep too little stock. If stock cannot be kept, the
humus can be maintained by catch-crops and cover-crops.
7. The fertility of the land is its power to produce crops. It is
determined by three things : the texture of the soil, its richness in
plant-food, and its available moisture.-The texture of the soil is
its physical condition,--as to whether it is mellow, loose, leachy,
cloddy, hard, and the like. A rock or a board will not raise
corn, and yet it may contain an abundance of plant-food. The
plant cannot get a foothold ; and it would do no good to apply
fertilizers. Spreading potash on a lump of clay is not farming :
it is the wasting of potash. A cow will not appreciate the fan-
ciest ration if she is uncomfortable; neither will a plant. It is
only on land which is in good tilth that fertilizers pay. The
better the farming, the more it will pay, as a rule, to buy plant-
food; but poor farmers cannot make it pay.
8. Nature secures good texture in soil by growing plants in it.-
Roots make the soil finer, and plants supply it with humus.
Plants break down the soil by sending their roots into the
crevices of the particles, and the root acids dissolve some of it.
Observe Nature working at this problem. First the moss or
lichen attacks the rock ; the weather cracks it and wears it away ;
a little soil is gathered here and there in the hollows; a fern or
some other lowly plant gains a foothold; year by year, and cen-
tury by century, the pocket of soil grows deeper and larger ;
and finally, the rock is worn away and crumbled, and is ready to
support potatoes and smart-weed. Or, the rock may be hard and
bare, and you cannot see any such process going on. Yet, even
then, every rain washes something away from it, and the soil
beneath it is constantly receiving additions. Some soils may be
said to be completed: the rock is all broken down and fined.
Other soils are still in process of manufacture : they are full of
stones and pebbles which are slowly disintegrating and adding
their substance to the soil. Did you ever see a rotten stone ?"
The longer plants are grown on any soil, and returned to it,
the richer the soil becomes. But Nature has centuries at her
disposal; man has but a few short years and must work rapidly,
and he cannot afford to make mistakes.
9. The texture of the soil may be improved (r) by under drain-
ing (2) by tilling (3) by adding vegetable matter (4) by adding cer-
tain materials, as lime, which tend to change the size of the soil par-
ticles.-The reader will say that Nature does not practice tile-
draining. Perhaps not ; but then, she has more kinds of crops to
grow than the farmer has, and if she cannot raise oats on a cer-
tain piece of land she can put in water-lilies. We shall have an
entire lesson devoted to drainage and tillage, and also one to
manures and fertilizers. It is enough for the present to say that
the roots which are left in the ground after the crop is harvested
are very valuable in improving the soil. This is particularly
true if they are tap-roots,-if they run deep into the soil.
Clover bores holes into the soil, letting in air, draining it, warm-
ing it and bringing up its plant-food. Roberts reports (" Fer-
tility of the Land," p. 345) that a second growth of clover, two
years from seeding, gave a yield of air-dried tops of 5,417 lbs.
per acre, and of air-dried roots 2,368 lbs. in the first eight inches
of soil. Add to this latter figure the weight of roots below
eight inches and the stubble and waste, and it is seen that the
amount of herbage left on the clover field is not greatly less than
that taken off. In this instance, the roots contained a greater
percentage of nitrogen and phosphoric acid than the tops, and
about the same percentage of potash.
Make an estimate of what proportion of the plant growth you
raise is actually taken off the field. Figure up, as accurately as
you can, the portion left irl roots, stubble, leaves and refuse.
Even of maize, you do not remove all from the field. This cal-
culation will bring up the whole question of the kind of root- sys-
tem which each sort of plant has. Have you ever made a close
examination of the roots of potatoes, maize, wheat, clover,
cabbages, buckwheat, strawberries, Canada thistles, or other
crops ? From what part of the soil do these plants secure their
nourishment ? What power have they of going deep for water ?
What proportion of them is root ? Because the roots are hidden,
we have neglected to examine them.
Io. The soil is plant-food; but this food becomes usable or availa-
ble slowly.-Roberts has compiled the analyses of 49 representative
soils, made by American chemists, and the following is the
result: The tables reveal the fact that even the poorer soils
have an abundance of plant-food for several crops; while the
richer soils in some cases have sufficient for two hundred to three
hundred crops of wheat or maize. The average of 34 analyses
gives to each acre of land, eight inches deep, 3,217 pounds of nitro-
gen, 3,936 pounds of phosphoric acid, and 17,597 pounds of pot-
ash, and this does not include that which is contained in the stones,
gravel and sand of the soil which will not pass through meshes
of one-fiftieth of an inch, which, by weathering and tillage,
slowly give up their valuable constituents.-Roberts' "Fertility
of the Land," p. 16.
Fortunately, this great store of plant-food is locked up, else it
would have leached from the soil or have been used up long ago.
By careful husbandry, a little of it is made usable year by year;
and the better the management of the land the more of this food
is available to the plant. When the farmer has done his best to
get out of the land all that it will give him, then he may add
fertilizers for bigger results.
Plant-food is available when it is in such condition that the
plant can use it. It must be both soluble and in such chemical
form that the plant likes it. Plant-food which is not soluble in
rain water, may still be soluble in soil water (which contains
acids derived from the humus) ; and the acid excretions from the
roots may render it soluble. But solubility is not necessarily
availability, for, as we have said, the materials must be in such
combination that the plant will tale them. Thus, nitrate of
soda (Na NO,) is available because it is both soluble and in the
form in which the plant wants it. But nitrite of soda (Na No,)
is not available although it is soluble,-the plant does not like
i i. Nitrogen must probably be in the form of nitrates before it
can be used by most plants.-Nitrogen is abundant. It is approx-
imately four-fifths of the atmosphere, and it is an important con-
tent of every plant and animal. Yet, it is the element which is
most difficult to secure and to keep, and the most expensive to
buy. This is because the greater part of it is not in a form to be
available, and because, when it is available, it tends to leach from
the soil. It is available when it is in the form of a nitrate-one part
of nitrogen, three parts of oxygen, united with one part of some
other element (Na NO,, nitrate of soda; K NO,, nitrate of pot-
ash or saltpetre ; H NO,, nitric acid, etc.). The process of chang-
ing nitrogen into nitrates is called nitrification. This process is
the work of germs or microbes in the soil; and these germs work
most efficiently when the soil is not water-logged, and when it is
well tilled. The farmer should make his nitrogen supply as he
goes along; and he makes it with tile drains, plows, harrows
But there are some plants which have the power of using the
nitrogen which is in the air in the soil. These are leguminous
plants, clovers, peas, beans, vetch, alfalfa. If therefore, the
farmer cannot secure sufficient nitrogen by other means,
he may use these plants as green-manures. If his system of
farming will not allow him to use these plants, or if he does not
secure sufficient nitrogen when he does use them, then he can go
to the warehouse and buy nitrogen.
12. The soil is not a mere inert mass : it is a scene of life and
activity.-This is the new and the true teaching. Soil which is
wholly inactive is unproductive. Movements of air and water,
actions of heat and evaporation, life-rounds of countless micro-
scopic organisms, decay and disintegration of plants and soil
particles,-these are some of the activities of the fertile soil. If
our ears were delicate enough, we could hear the shuffle of the
workers, the beating of the hammers, and the roll of the tiny
machinery. All things begin with the soil and at last all
things come back to it. The soil is the cemetery of all the ages,
and the resurrection of all life. If the soil is not idle, neither
should the farmer be.
NOTE. Persons who desire to pursue this subject further should procure
King's book The Soil and Roberts' Fertility of the Land." Published
by the Macmillan Co., New York, at 75 cents and $1.25 respectively.
This Reading-Lesson is sent free to all persons in New York State
who are interested in agriculture. A supplement or quiz accom-
panies it, asking questions on the Lesson. Those who answer these
questions will receive subsequent issues of Lessons. These Lessons
are published by the College of Agriculture, Cornell University.
The Reading-Lessons now cover three principal topics. the soil
and the plant; dairying and cattlefeeding; fruit growing. The
subject matter of these Lessons will be of the nature of review work
for some, while to others the principles as such will be new. I
trust they will be interesting and useful to all.
Farmers' Reading Course,
Ithaca, N. Y.
John Craig, Supervisor,