and grasses, to double the productive capacity of thousands of acres of
our western corn and wheat lands. This is shown by the experiments at
the Kansas Station and by the reports of farmers. In 1906, a careful
investigation of the corn yields of Jewell County, Kansas, made by Hon.
J. W. Berry, formerly a member of the board of regents of the Kansas
State Agricultural College, showed that the average yield from land
previously in alfalfa was over eighty bushels per acre, while similar
land on the same farm and adjoining farms, which had not been in alfalfa,
yielded less than sixty bushels per acre on the average, and the average
yield of corn in Jewell County for that year was less than thirty bushels
per acre.
It has been shown by the experiments carried on for the last six years
at the Station that it is possible to increase the yield of corn ten per
cent simply by practicing better methods of preparing the seed-bed. When
corn has been planted with the lister, winter or early spring plowing or
listing of the ground previous to the planting has given an increase in
crop as an average for six years, amounting to six bushels of corn per
acre each year, as compared with ground which received no cultivation
previous to planting.
Different methods of cultivation of corn, deep or shallow, etc., have
not affected the yield so much as different methods of preparing the
seed-bed, except where the cultivation of the corn was neglected. The
lack of sufficient cultivation means greatly reduced yields or crop
failure.
It is possible to increase the wheat yield of Kansas fifty per cent by
practicing better methods of seed-bed preparation. As an average for
two years’ trials, 1908 and 1909, at the Station the yield of wheat due
to preparation of seed-bed alone varied from 21.6 to 37.4 bushels per
acre, an increase of seventy-three per cent in yield due to the better
preparation of the seed-bed.[6]
[6] See Kansas Experiment Station Circular, 2.
In 1911, one of the driest years which Kansas has ever experienced, this
experiment was repeated with remarkable results. The most poorly prepared
seed-bed (ground disked, not plowed) yielded a little over four bushels
of wheat per acre, while the largest yield was thirty-eight bushels per
acre from early deep plowing, which received frequent cultivation after
plowing until seeding time. Ordinary loose ground, plowed late, yielded
fourteen bushels per acre, while ground cultivated early with the lister
plow and leveled with the disk harrow gave thirty-five bushels per acre.
The better methods of seed-bed preparation employed in these experiments
are such as may be successfully practiced throughout the Western winter
wheat belt.
Of the three factors concerned with increasing the acre-yields, the last
named, “Practicing Proper and More Thorough Cultivation of the Soil,”
is the simplest and most readily applied. Probably more low yields and
crop failures are due to insufficient or improper cultivation than to any
other single factor over which the farmer has control in the production
of any particular crop. With a soil of average fertility, the preparation
of the seed-bed by the proper tillage and cultivation methods very
largely determines the yield of the crop.
There are four important objects to be accomplished by cultivating the
soil: 1. To secure a proper physical condition of the soil favorable
to sprouting seed and promoting plant growth. 2. To kill weeds. 3. To
conserve soil moisture. 4. To develop or prepare plant food.
The texture of the soil is nearly always more important than mere
richness. Many “worn” lands have simply been robbed of their organic
matter, often still containing an abundant supply of the mineral
elements of plant food. Others have been injured in texture and hence in
productiveness by careless or faulty management.
The maintenance and improvement of soil texture are more dependent upon
plowing than upon any other operation of tillage. A finely divided,
mellow soil is more productive than a hard lumpy one of the same chemical
composition, because it affords greater feeding ground and more favorable
environment for the plant roots; absorbs and retains more moisture, has
better aeration, and less variable extremes of temperature. Also, because
it promotes nitrification and the development of available plant food by
giving favorable conditions for the development of soil bacteria, and for
the decomposition and solution of the soil minerals. In all these ways
and others, “mellowness” renders plant food more available and affords a
more congenial, comfortable place in which the plants may grow.
Plowing, especially in the spring, tends to ventilate, warm and dry the
seed-bed, and if properly done, lessens evaporation from the deeper soil
by the development of a soil mulch above it.
Deep plowing brings up new stores of inert plant food, enlarges the
moisture reservoir, deepens the seed-bed, gives more root room and more
material for the soil bacteria to work over into available plant food.
Deep plowing or subsoiling also serves to break up the plant food, to
break up the “furrow-sole” or “hard-pan,” thus loosening up compact,
impervious, clayey subsoils.
Plowing is an efficient means of destroying weeds and many kinds of
injurious insects which prey on farm crops. Hard, clayey or “gumbo” soils
are mellowed by late fall or winter plowing, and further, proper and
timely plowing is the most efficient and practical means of preparing a
suitable seed-bed for nearly all farm crops. Too many farmers who have
allowed their land to become deficient in fertility seek to restore its
productivity by application of expensive commercial fertilizers, without
first putting it in good tilth. This is a great mistake. The way to treat
such land is to “plow” it well, and work up a physical condition suitable
for the best growth of crops. After all this is done, the application of
concentrated commercial fertilizers may give profitable returns.
In order to secure the ideal condition for seed germination and plant
growth, a seed-bed for planting small seeds should not be too deep and
loose; rather the soil should be mellow, but well pulverized only about
as deep as the seed is planted. Below the depth at which the seed is
planted it should be firm and well settled, making a good connection with
the subsoil, so that the water stored therein may be drawn up into the
surface.
The firm soil below the seed, well connected with the subsoil, supplies
the moisture to the seed, while the mellow soil above it allows
sufficient circulation of air to supply oxygen and favors warming by
gathering the heat of the sunshine during the day and acting as a blanket
to conserve the soil heat, maintaining a more uniform temperature during
the night.
The mellow soil above the seed conserves the moisture, acting as a mulch
to keep the water from reaching the surface, where it would be rapidly
lost by evaporation. The same condition favors the upward growth of the
young shoots into the air and sunshine.
The loose, deep seed-bed is almost wholly dependent upon rains for
sufficient moisture to germinate the seed and start the young plant.
If the crop starts, it is very apt to be injured by short periods of
dry weather, because of the rapid drying out of the loose surface soil.
In such a seed-bed the crop is more apt to “burn out” in the summer,
or “freeze out” in winter, than a crop grown in the “ideal” seed-bed
described above.
It should not be inferred from this description of the “ideal” seed-bed
that the soil should not be plowed deeply; rather, deep plowing should
be encouraged, but timely, so that the soil may settle and fill with
moisture, and such cultivation should be given after plowing, so as to
secure a favorable physical condition of the seed-bed.
So far as cultivation is concerned there are three principal steps in the
conservation of soil moisture:
1. The soil must be loosened to a considerable depth in order to prepare
a reservoir to receive the rain and carry the water downward. This may be
accomplished by deep plowing, by listing, or by disking unplowed lands.
2. The water which is carried down into the subsoil must be brought
back again into the surface where the seed is germinating and the young
roots are growing, and to accomplish this a good connection must be made
between the furrow-slice and the subsoil, and this is the purpose in the
use of the subsurface packer immediately after plowing.
3. Finally, in order that the water which is drawn up again towards the
surface may not reach the air and be wasted by evaporation, the upper two
or three inches of the soil must be kept mellow in the form of a soil
mulch, and this is accomplished in the growing of crops, by frequent
cultivation, which is not so practicable with wheat, and other small
grains, as with corn and other intertilled crops.
The most important step in soil moisture conservation is to get the water
into the soil. When this has been accomplished, the keeping it there
and returning it gradually to the growing crop is a relatively simple
matter. Many farmers have yet failed to learn this most important fact
of dry farming, that the storing of the moisture is the first and great
principle of soil moisture conservation. The firming and pulverizing to
prepare the seed-bed, and the surface cultivation to maintain the mulch,
are each without avail unless there has been stored in the deeper soil
a sufficient amount of moisture to support the growing crop in time of
drouth.
Now the moisture should be stored at all times during the season, but
especially during the interval between harvest and planting. This
requires early plowing so that the soil may be in condition to catch the
rain and absorb it.
In order that there may be room to receive and store a heavy rain, deep
plowing is desirable. If plowing can not be done early, the cultivation
of the unplowed land with a disk harrow will keep the soil in good
condition longer and favors the absorption of rain.
A good rule, but it cannot always be followed, is to plow when the soil
is in such condition that it will drop from the mold-board in a mellow,
friable condition.
Loosening the soil by deep plowing favors the absorption of moisture,
but if rains do not come in time such land will suffer from drought more
quickly than though it had been plowed shallow.
The loose soil dries out and capillarity is broken, preventing the
furrow-slice from receiving moisture from the subsoil rapidly enough
to sustain the growing crop. The depth and frequency of plowing should
vary according to the nature of the soil. A light or sandy soil requires
less depth of plowing and less frequent plowing than a heavy, or compact
clayey or “gumbo” soil.
As a general proposition, plowing should be shallow when it precedes
planting only a short time.
Plow deep in the fall, and plow deep for summer fallow.
A long interval between plowing and seeding allows the soil to settle
sufficiently, while freezing and thawing mellow the raw, hard subsoil
which has been brought to the surface.
The relative depths of plowing may be stated as follows:
Shallow plowing 3 to 4 inches.
Medium plowing 5 to 6 inches.
Deep plowing 7 to 8 inches.
Plowing deeper than eight inches with the common plow is not usually
practicable, but the soil may be stirred twelve to eighteen inches deep
with a tillage plow or subsoil plow, and in heavy soil with hard, compact
subsoil, such deep stirring may occasionally be desirable.
When land is allowed to lie for a considerable period after plowing
before the crop is planted, the settling of the soil, together with the
surface cultivation to preserve the mulch and the cementing due to rain,
usually causes it to repack and firm up to a sufficient extent to make a
good seed-bed.
The use of the packer is most essential on late spring plowing, when the
purpose is to plant at once. It is not so necessary to use the subsurface
packer on fall plowing which is not intended to be planted until the
following spring, but for sowing fall wheat, if the plowing precedes the
sowing by a very short interval, the subsurface packer may be used very
advantageously.
The principle involved in the use of the subsurface packer is correct,
and the lighter the soil and the greater its tendency to remain loose and
mellow the more necessary becomes the use of the subsurface packer or
similar implement, in order to prepare a proper seed-bed.
In plowing under trash or manure, subsurface packing, by pulverizing the
bottom of the furrow-slice, sifts the soil through the coarse trash and
causes a better union with the subsoil below, so that the capillary water
may be drawn up into the surface, whereas, if a heavy coat of stubble or
manure plowed under in this way is left without packing or pulverizing,
the furrow-slice is apt to dry out and the crop that is growing on the
land may be injured by a short interval of dry weather.
By setting the disks rather straight and weighting the harrow, a
disc-harrow may be used as a substitute for the subsurface packer,
resulting in a pulverizing and firming effect at the bottom of the
furrow-slice. Very often, however, early plowing, with the proper use
of the common harrow, may largely accomplish the results required in
preparing a proper seed-bed. It is usually advisable to weight or ride
the common straight-tooth harrow in order to cause it to stir and
pulverize the soil deeper and prevent the “slicking” effect which is apt
to result from light harrowing.
The cultivation necessary, after early plowing, to destroy weeds, in
the experience of the writer, has usually been sufficient to settle and
pulverize the seed-bed. For the early cultivation after a good rain and
after the weeds have started, there is no implement superior to the disk
harrow. The double disk which gives two cultivations and leaves the
ground level, being preferred. For late cultivation the common harrow
or the Acme harrow should be used with the purpose of not loosening the
ground too deeply just previous to planting or seeding.
It is very essential that sufficient and proper cultivation be given to
destroy weeds. This is more important than to maintain a soil mulch,
since weeds exhaust both the soil moisture and the available plant
food. If a proper mulch is maintained, however, the weeds will be kept
in subjection. In the ideal system of culture the purpose is to keep a
mellow soil mulch on the surface of the land all of the time, not only
during the growing of the crop, but also in the interval between harvest
and seeding time. Thus, after the corn is planted the land is cultivated
with the weeder or harrow in order to break the surface crust and
prevent the loss of moisture, and following out the same principle the
harrowing or work with the weeder is continued after the grain or corn is
up, and during the growing period frequent cultivation is required for
intertilled crops.
Again, after the crop is harvested, the cultivation is continued;
the land is plowed at once or listed, or the surface of the soil is
loosened with the disk harrow, and thus the land is kept continually
in a condition to not only prevent the loss of water already stored in
the soil, but also this same condition and mellow surface favors the
absorption of rain and largely prevents the loss of water by surface
drainage.
The smooth, finely-pulverized surface left by continuous light harrowing
really defeats the purpose of the cultivation, since soil in such
condition will shed heavy rains, causing a waste of water which should
have been stored, and the surface often becomes too fine and compact,
preventing the proper aeration, and producing an unfavorable seed-bed
condition. Thus during the interval between crops, it is often advisable
to use the Acme harrow or the disk, or spring-tooth harrow, in order to
keep the surface of the soil open and mellow.
A new method for preparing the seed-bed is now coming into general
practice in Western Kansas. In preparing land for wheat, the plan is to
list the ground with the ordinary corn lister as soon after harvest as
possible. The lister furrows are run about three to three and a half feet
apart, very much the same as when the lister is used for planting corn.
Later, when the weeds have started, the soil is worked back into the
lister furrows by means of a harrow or disk cultivator.
Several cultivations are usually required by the harrow, and disk harrow,
in order to level the field and bring it into good seed-bed condition.
Once over with the disk cultivator is usually considered sufficient,
the further work necessary to prepare the seed-bed being given with the
common harrow or other cultivating implement.
In a dry climate this method of preparing the seed-bed has several
advantages, as follows:
The cultivation of the land soon after harvest tends to conserve the
moisture already stored in the soil. The furrowed land is in good
condition to catch and store the rain and the later cultivation clears
the land of weeds and volunteer wheat and leaves a mellow soil mulch to
conserve the moisture which has been stored in the subsoil. The early and
continued cultivation of the soil favors the action of the bacteria and
the development of available plant food.
By practicing this method the farmer may cultivate a larger area early
in the season when the soil is in good condition, when if it had been
necessary to plow the whole area, some of the land might become too dry
to plow well. Likewise the later plowing leaves the soil too loose and
not in good seed-bed condition. In preparing land for corn, the listing
may be done late in the fall or during the winter, or early spring. The
usual plan being to split the ridges with the lister later in the spring
when the corn is planted. It is advisable to harrow the listed field
once or twice before planting to destroy weeds, or prevent soil drifting
and to preserve a mellow soil mulch to conserve the water which has been
stored in the subsoil. In preparing land for corn, the early listing has
proved equal to early plowing and superior to early disking, as shown by
the experiments at the Kansas Station.
In the drier portions of the great plains area and throughout the
mountain states, where dry farming is practiced, the annual rainfall is
not sufficient to produce a crop every year, and it becomes necessary to
practice a system of summer fallowing every third or fourth season, or
in alternate years in localities of least rainfall, in order to store
moisture and develop plant food and thus insure the production of a
profitable crop each year.
Deep plowing either in the fall or spring, and frequent surface
cultivation as described above is the method of summer fallowing which
has given the best results at the Montana, Western Nebraska, and Western
Kansas Experiment Stations.
The weeder is better adapted for harrowing wheat and other small grains
than the common harrow, but the harrow may be used when the ground is
firm. I question whether it is necessary or advisable as a rule to harrow
wheat if due precautions have been taken in preparing the seed-bed.
Under certain conditions, where heavy rains firm and puddle the soil,
it may be advisable to harrow, but very young grain may be injured
by harrowing, and after the wheat covers the ground, harrowing is
unnecessary. The harrowing of wheat at regular intervals at the Kansas,
Nebraska and Montana Experiment Stations has not resulted favorably.
Without question, the proper preparation of seed-bed is a much more
important factor in the growing of small grains, than the cultivation
after seeding.
While it is a disputed point among authorities whether it pays to harrow
wheat and other sowed crops, there is no difference of opinion regarding
the necessity or value of frequent cultivation of corn and of all other
crops usually planted in rows. Regarding the depth and frequency of
cultivation desirable, I favor rather deep cultivation in our drier,
hotter climate, and after every hard rain, if possible, or at least
sufficient to keep the weeds in check.
It is not necessary or practicable to attempt to cultivate after every
rain and there is no virtue in the admonition “Keep the Cultivator going
in a dry time.” If the soil has been well stirred and the mulch is of
sufficient depth, to cultivate again would be loss of time and might do
actual harm by drying out the deeper portions of the soil mulch and also
causing a too fine and dusty condition of the surface soil, unfavorable
to the absorption of moisture when the rain comes.
It is not necessary to have extra machinery in order to successfully
practice the system of culture outlined above. The only implements
required or recommended which are not in general use on every well
equipped farm, are the subsurface packer and the weeder.
The principles stated above have been known and practiced more or less
for a long time and are mostly included in the “Campbell” system of
culture. H. W. Campbell was among the early apostles of dry farming in
the West, and has perhaps done more to call the attention of western
farmers to the necessity and advantages of thorough cultivation of the
soil than any other investigator.
Scientific farming pays, everywhere. I believe in the practicability of
thorough tillage and good cultivation on every farm, and the increase in
crops by such farming will more than pay for the extra labor. But the
great problem in Western agriculture today is not how to get larger crops
out of the soil for a few years, but rather how to produce paying crops
every year and at the same time maintain the fertility and productiveness
of the land.
Simple tillage will not maintain soil fertility. It becomes necessary
finally to replace the plant food, exhausted by the continuous growing
of crops, with the application of manure, or chemical fertilizers, and
by green manuring and the rotation of crops, in which the legume crops,
such as alfalfa and clover are introduced in order to restore again the
nitrogen and organic matter, the supply of which has only become more
rapidly reduced because of intensive cultivation.
There is little question regarding the value and even the necessity of
the summer fallow in the drier areas of the West. The tests at a number
of Western stations and the general experience of farmers prove this; yet
there are serious objections to the continued practice of bare summer
fallowing.
First, there is the tendency for the soil to waste by drifting in strong
winds and by washing away in heavy rains.
Second, summer fallowing with frequent cultivation hastens nitrification
and decay, thus more rapidly exhausting the organic matter in the soil.
It is possible for the soil to become more rapidly exhausted in fertility
by alternate bare summer fallowing and cropping than by continuous
cropping. At least the bare summer fallow does not add any fertility to
the soil. In order to maintain the productivity of our Western lands, it
will become necessary to add fertility to the soil preferably during the
year of fallowing.
I am beginning the practice of a method of green manuring and partial
summer fallowing, which I believe to be superior to bare summer fallowing
and which will largely overcome the objections to summer fallowing.
The plan is to plant some fall crop or early spring crop and plow it
under late in May or early in June, practicing a summer fallow with
surface cultivation for the rest of the season, until seeding time.
Certain crops adapted to the West are being tested for this purpose with
some degree of success. The more promising are sweet clover and sand
vetch for fall seeding and field peas for early spring seeding. These
crops are hardy, rapid growers, and somewhat drouth resistant and may
be used also in part for pasture, thus giving some return other than
their fertilizing value. Some experiments have already been made at the
Hays Station in Western Kansas and the yields of wheat secured from the
green-manuring summer fallow compare favorably with the yields from
the bare summer fallow. And in my judgment, this method of fallowing
will soon be generally adopted and will solve the problem for a long
time at least, of increasing the organic matter and maintaining the
productiveness of our western lands.