(IIi(1 LAH NO. IS A\UGUST, 
1923
Alabama Agricultural Experiment Station
Alabama Polytechnic Institute
AUBURN
1) N TU. (W , Ilir('0lur
I( Y1Ijii'iCS
SOil
in] {cltil to
Fcrti litv,
I;- V
SOIL, DIVISIONS OF ALABAMA ARE SHOWN ON
THIS MAP
5CAM BiA ~ ~ i/OUS
DLO ?I (OAST 'Pu G LACIC BELT
PPP2 CWAST P1IALU'. PIEDr ANT
OAAA CM NPiATEAXI
?LI'LTONiYA QY EIIGL1PNORIII
SUMMARY
1. The chief needs of Alabama soils, from a fertil-
ity standpoint, are nitrogen and organic 
matter.
2. These needs can be supplied most economically
by the addition of both summer and winter legumes
to the cropping system.
3. The maintenance of an adequate supply of phos-
phorus and, on many soils, the use of lime, are 
neces-
sary for the most successful growth of most winter
legumes.
4. A cover crop of vetch has returned a 
net profit
of approximately $10.00 per acre in experiments 
at
Auburn. (See Table 1.)
5. The yield of corn planted continuously on the
same land has been approximately maintained 
for 27
years by planting peas in the corn middles at the last
cultivation, and the peas turned under for the next
crop of corn. (See Table 1.)
6. Corn planted continuously on the same land, but
without peas at the last cultivation, has declined in
yield to approximately 50 per cent of the yields ob-
tained in earlier years. (See Table 1.)
7. Cotton yields have been more than doubled, and
corn yields nearly doubled, by the addition of peas
and clover in a three year rotation at Auburn. (See
Table 2.)
8. The use of lime may be very profitable. One
dollar invested in lime has returned $8.50 in the ex-
periments at Jackson, Clarke County. (See Table 3.)
9. Vetch, crimson clover, annual yellow melilotus,
and bur clover are the best cover crops for Alabama
conditions. A full discussion of these as winter cover
crops may be found on pages 12-19.
LEGUMES IN RELATION TO SOIL FERTILITY
By M. J. FUNCHESS*
One of the most important problems 
confronting the
farmers of Alabama is that of increasing the fertility
of their farms. Rural communities which secure low
crop yields are not in a position 
to maintain good
homes, good roads, good schools, and 
good churches.
All of these are necessary for a healthy 
and contented
rural population. It is obvious, therefore, 
that the
general welfare of the State is quite largely 
dependent
upon the fertility of her farms.
A fertile soil must contain a good supply of nitrogen,
phosphorus, and potassium available 
to plants. In
addition, the soil must not be too acid or sour, for an
acid condition is unfavorable to the best growth of
many crops. The problem of maintaining or increas-
ing soil fertility may be stated briefly as follows:
Which of the fertilizing elements mentioned above are
most needed, and how can they be supplied most eco-
nomically? Experiments conducted in many parts of
the State have shown that Alabama soils are most in
need of nitrogen and organic matter. Therefore, if
the fertility of Alabama farms is to be increased, 
the
first and most necessary thing to do is to provide a suf-
ficient and continual supply of nitrogen and organic
matter.
Nitrogen may be added to the soil in two ways. It
may be purchased in commercial fertilizers, or it may
be added by growing leguminous crops such as vetch,
clover, peas, and beans, and plowing these crops under;
or by feeding them to livestock, and carefully return-
ing the manure to the land. Leguminous crops, when
well inoculated, secure most of their nitrogen from the
air. A good crop of hairy vetch or bur clover, when
plowed under, will add as much nitrogen to the soil as
is contained in 400 pounds of nitrate of soda. It
is possible to maintain and increase the amount of
nitrogen in the soil by so arranging the cropping sys-
tem that full use be made of legumes for soil building
purposes. In most instances, this will not involve any
*Acknowledgement: Data recorded in Table 1 are taken
from the records of experiments planned by Prof. J. F. Dug-
gar in 1896, and were continued under his direction until
1921. The data in Table 3 are taken from the record of ex-
periments planned by Prof. J. F. Duggar and Mr. J. T. Wil-
liamson in 1916, and supervised by Mr. Williamson since that
time.
radical change in the present 
cropping system. For
example, the farmer who grows 
cotton and corn chief-
ly, needs only to follow his cotton 
with some winter
growing soil building crop, and to 
plant peas or beans
in his corn. All that is needed is that 
full use be made
of crops that the climate of Alabama 
permits to be
grown, and rapid progress can 
be made in building
up soils and increasing crop yields.
The position of phosphorus and potash in a soil -fer-
tility program should be clearly understood. There is
no way to increase the amount 
of phosphorus and pot-
ash in a soil except by additions in the form of some
kind of fertilizer material. When a cover crop 
is grown
and turned under, certain amounts of these two fer-
tilizer elements may be changed into forms that are
more available for the following crops; but there is no
increase in the stock supply of the soil 
when such a
procedure is followed. The experimental work con-
ducted by the Alabama Experiment Station has demon-
strated very conclusively that many Alabama soils are
too deficient in phosphorus to grow good crops of leg-
umes, and that it is necessary to increase the supply
of phosphorus in such soils before a satisfactory crop
of legumes may be grown. On the other hand, there
is apparently no need for an application of potash fer-
tilizer for such crops.
The use of lime is still another factor in a soil fer-
tility program. Wherever soils are found to be very
acid, applications of lime will be necessary for the best
growth of any but acid tolerant crops. This topic is
discussed on page 10.
Summarizing a soil fertility program, there are the
following points:
1. The fullest possible use of both summer and win-
ter legume crops for the purpose of increasing the or-
ganic matter and nitrogen content of the soil.
2. Maintenance of a plentiful supply of phosphorus
in the soil by additions of phosphatic fertilizers.
3. Applications of lime to those soils that are found
to be so acid as to need lime for a satisfactory growth
of soil building crops.
This program is simple, inexpensive, and makes pos-
sible the maintenance of the soil nitrogen which is the
most expensive fertilizer element. It also makes pos-
sible the maintenance of the supply of organic matter,
a material that is impractical to purchase. Commer-
cial fertilizers must play an 
important part in such a
program, but it is hopeless to depend on them
alone. The maximum return can be had from 
manu-
factured fertilizers only on those soils 
that are ade-
quately supplied with organic matter, since this ma-
terial markedly influences the water holding capacity
of the soil, and lessens drought damage.
The Alabama Experiment Station has conducted a
number of experiments to demonstrate the value of
the 'fundamental principles set forth above. The ob-
ject of this circular is to present briefly the results ob-
tained in such experiments, and to explain how crop
yields may be materially increased, thus producing
more profit from the labor expended on each acre of
land.
RESULTS OBTAINED IN SOIL FERTILITY EXPERIMENTS
The Value of Legumes in Rotations.-The value of
legumes as soil building crops is well shown by 
long
continued experiments conducted on the Alabama Ex-
periment Station farm, the results of 
which are re-
ported in Table 1. Plot 1 in these experiments is
planted to corn each year, with peas planted 
in the
corn middles at the last cultivation. The peas pro-
duced are turned under for the next crop of corn. Plot
2 is also planted to corn each year, but no peas are
planted in the corn middles. The marked 
decline in
yield on plot 2 shows what may be expected when land
is cropped continuously, and no effort made to keep
up the fertility of the soil. During the 27 years that
this work has been in progress, the yield of corn on
plot 2 has steadily declined, until it is now producing
but half as much corn as plot 1.
The value of legumes is further shown by the results
obtained from other plots in this experiment. 
Plot 6
has been planted to cotton continuously without leg-
umes for soil building purposes. The yield of cotton
has fallen from 803 pounds in the first ten year period,.
to 360 pounds as the average for the last three years.
Plots 3 and 8 are also planted to cotton each year, but
vetch is planted on these plots in the fall, to be turned
under the following spring as green manure for cot-
ton. During the first 10 year period these two plots
produced an average yield of 813 pounds of seed cot-
ton per acre; and an average of 602 pounds in the last
three years. When 
valued at 6 cents per 
pound, the
seed cotton produced 
by the plots carrying 
a cover
crop of vetch is worth 
$14.52 more than cotton 
pro-
duced by plot 6, which gets no 
cover crop. The cost
of the vetch seed plus the cost 
of planting would not
amount to more than $4.50 
per acre, thus leaving 
a
profit of approximately $10.00 from the 
use of a cover
crop. Plots 5 and 9 are worked into 
a two year rota-
tion of cotton and vetch one year, followed 
by peas
to be turned under for cotton the next year. This
treatment has produced a yield of cotton that is actual-
ly greater than that obtained in the earlier years of
the experiments. The accumulated data and the de-
tails pertaining to these experiments are given in
Table 1.
Table 1.-The Effect of Legumes Turned Under on the Yields
of Succeeding Crops
CORN--BUSHELS
Average yield
of crops
Plot Fertilizers, Cropping 
system ?
No. Lbs. per acre
Bus. Bus. Bus.
1 IAcid phos._ _160 Corn each year, peas
Kainit _160 at last cultivation 19.2 16.2 17.4
2 Acid phos. _1601 Corn each year,
Kainit ---- 1601 no peas 17.1 10.2 8.8
SEED COTTON-POUNDS
Lbs. Lbs. Lbs.
6 Acid phos.._160 Cotton continuously.
Kainit .. 160 No legumes I 803 573 360
3,81 Acid phos. -160 Cotton continuously.
I Kainit 160 Vetch as cover crop 813 678 602
5, 9 Acid phos.-.-1601 Cotton and vetch. I I
Kainit .... 1601 Cowpeas I 890 958 1042
The plots used in the experiments discussed above
have been fertilized exactly alike for 27 years, so that
the differences in yields now being obtained are due
solely to the use of legumes for soil building. Special
attention is called to the fact that the vetch crops grown
on the plots have never been very satisfactory, but the
poor growth is now known to be due to the lack of
available phosphorus in the soil. Had these plots
been well fertilized with phosphatic fertilizers in-
8
stead of only 160 pounds per 
acre each year, doubt-
less the results would have been more 
striking.
1LtCuiiw Tumin UNDER 1cfs. Crop YiuDks
-. EPLO
CoT TOM
)T 2. CoRN AI~oINx
PLOT 1 t Coh ANI P~A
PLOT 6. COTTON A oNW.
'SO. C0TTOIV VTC~i
P
0
jooT T'ro& Vicli
PT 0 'Cw Thn
RUM w Qr. ,6.COT
The value of legumes when used in the cropping sys-
tenm is clearly shown by the data presented 
in Table 2.
In these experiments cowpeas and crimson clover 
are
used as fully as possible in a three year 
rotation of
cotton, oats, and corn. The reader should note care-.
fully that plots A and B are fertilized exactly alike, the
only difference in treatment being the addition of peas.
and clover in the rotation on plot A. Table 2 follows:
Table 2.-The Effect of Legumes Turned Under, on Yields of-
Cotton and Corn Grown in a Three-Year Rotation
Average yield of
Plt Fertilizers, Copn 
ytm Seed ICorn
Lbs. per acre. cotton
3 yrs. 
9 yrs.
1Lbs. Bus.
A Acid phos.._ 2401 Three year rotation
Kainit--200 peas and clover for
soil improvement I 531 25.3
B I Acid phos. 2401 Three year rotation I
IKainit -- 2001 No peas or clover 227 14.2
C None Three year rotation .
IINo peas or cloverI 142 I 15.7
36:i5
60Z L SS
90 ;: LVSS
The peas and clover turned 
under for soil building
purposes on plot A have more 
than doubled the yield
of cotton, and nearly doubled the 
yield of corn, when
compared with the yields obtained on 
plot B. In re-
cent years the corn crop has been 
more than doubled
by turning under legume crops.
The Value of Lime.-The value of lime in a soil fer-
tility program can scarcely be overestimated. 
While
many soil building crops may be grown 
with a fair
degree of success without the use of lime, it is true that
lime benefits, to a profitable extent, most of 
these leg-
umes. The possible profits to be derived from the 
ap-
plication of lime is shown by the crop yields 
obtained
in experiments conducted at several places 
in Alabama.
Some of the results obtained in experiments at Jack-
son, Clarke County, are given in Table 3.
Table 3.-The Effect of Lime on the Yields of Cotton and Corn
Grown in a Three-Year Rotation
Seven year av-
No. Fertilizers, Cropping 
System erage yield 
of
Plot 
Cropping System
Lbs. per acre Corn Seed
Cotton
Bus. Lbs.
1,5,9 None Three year 
rotation
13 1 Peas and clover 
for
( soil improvement 18.6 425
6 Acid phos.__240 Three year rotation
C. S. meal __200 Peas and clover for
Kainit -- 200 soil improvement 23.8 619
10 Acid phos. _240 Three year rotation
C. S. meal _200 Peas and clover for
Kainit .. 200j soil improvement 25.4 781
Lime __2 tons
The fertilizer applied each year to plot 6 would cost
approximately $5.25, while the increase in yield of seed
cotton at 6 cents per pound for seed cotton would be
worth $11.64. Thus the annual profit from this amount
of fertilizer would be $6.39. The two tons of lime ap-
plied to plot 10 in 1916 cost approximately $8.00.
No lime has been applied since the initial application
was made. A comparison of plots 6 and 10 shows that
the lime applied to plot 10 has produced an annual
increase of 162 pounds of seed cotton, which at 6 cents
per pound was worth $9.72 per year, or $68.04 as the
gross return for eight dollars worth of lime applied in
10
1916. Still more interesting is the fact that the effect
of this one application of lime is greater in the seventh
year after application than it was in the earlier years
of the experiment. For example, lime applied in 1916
increased the cotton crop of 1922 by 248 pounds of seed
cotton, which, at 6 cents per pound, was worth $14.88.
The increase in this one cotton crop'was worth nearly
twice as much as the original cost of the lime.
L xMv. IN tc AA ,3COTTON4YEU~- B~
-CHvc~s. No FEAITIL1ZEP
,o' , 4ObL85. 
C OPXPLLhT1h
Piov6, FERT1L1Z hp-
P1OT 51 ?. COvVpLeTE
IL T10 ETitIZ1. &6 LIME
The increasing benefit that is being derived from the
lime applied should not be attributed to its direct ef-
fect on cotton and corn, but to its indirect effect 
on
these crops through increased crops of legumes 
that
are worked into the three-year rotation of cotton, 
corn,
and oats. Crinison clover is planted in both the cotton
and the corn middles in the fall; and 
cowpeas are
planted on the stubble land. The maximum 
benefit
can be derived from the use of lime only 
when full. use
is made of legumes in the cropping 
system. It is very
doubtful if lime will give profitable 
returns through
its direct effect on such crops as cotton, 
corn, and oats.
The results obtained in similar experiments 
conduct-
ed near Atmnore, Escambia County, 
indicate fully as
great returns from lime as those 
obtained at Jackson.
However, since only a partial 
record of this experi-
ment is available, the results will 
not be discussed in
detail.
In similar experiments conducted 
at Albertville, Mar-
shall County, lime has not produced 
as much profit as
j -elv ,If
11
is being obtained in the Atmore and Jackson experi-
ments, but is very profitable. The effect of 
lime
on crop yields at each of these three points is greater
at the end of the seventh year than it was the first year.
The results indicate, therefore, that an application of
two tons of lime per acre will show beneficial effects
over a long period of years, thus making the annual
cost of lime less than a dollar per acre.
It is not intended to convey the impression that
lime is needed on all the soils of Alabama; but on all
soils that are medium or strongly acid, lime will pay
very large profits when used as a means of increasing
the growth of soil building crops.
COVER CROPS ADAPTED TO ALABAMA CONDITIONS
The discussion given in the following pages is limited
quite largely to a few winter legume cover crops since
numerous experiments conducted at Auburn and at
other points in Alabama show that while it is possible
to grow many different kinds of winter legumes only
vetches, crimson clover, bur clovers, and annual yellow
melilotus have enough outstanding good points to war-
rant serious consideration at this time. Such well
known crops as cowpeas, velvet beans, soybeans, etc.,
are not discussed in detail in this publication.
Annual yellow melilotus (or sweet clover) is a relat-
ively new winter cover crop in Alabama, and has been
tested by the Experiment Station but two years. All
discussions dealing with this crop are based on a few
experiments conducted in 1921-22, and a large number
conducted in 1922-23. The conclusions drawn, 
there-
fore, should be considered as tentative, and subject to
change with later experimental work.
Varieties.-The four varieties of vetch 
that deserve
mention at this time are hairy, dasycarpa or Woolly
pod, Oregon, and Purple. Of these, hairy vetch has
been found to be generally adapted, and is recommend-
ed for all sections of Alabama. Woolly pod or dasy-
carpa vetch is a relatively new variety that appears to
be satisfactory in all parts of the State also. It makes
an earlier growth than hairy vetch, but appears to be
more susceptible to disease. In severe winters,. Oregon
and Purple vetches will very likely be severely dam-
aged by cold in the northern half of the state; but both
of these may do well in the southern part 
of Alabama.
12
Southern or spotted bur, and California bur clover
are the two varieties of bur clover commonly grown.
California bur clover is not sufficiently cold resistant
to warrant its general use in the northern half of the
State; but in the southern part of the State it has given
very satisfactory results. There is but one common
variety of crimson clover and of annual yellow meli-
lotus.
Need for Lime.-Vetch, crimson clover, and bur clov-
er, like cowpeas and velvet beans, may be grown on
most Alabama soils without the use of lime. In many
instances, however, lime increases the yield, and can
be used profitably. Of these three crops, vetch is less
likely to need lime, while bur clover is most likely to
respond to applications of lime.
The need for lime by annual melilotus is greater than
for either of the other crops under consideration, and
on many soils the crop will very likely fail unless lime
is applied. However, a farmer should have his soil
tested for acidity before planting yellow melilotus*.
Need for Phosphatic Fertilizers.--Vetch, crimson clov-
er, and yellow melilotus give only a slight response
to phosphatic fertilizers on the sandy soils of the south-
ern part of the State, and good crops may be grown
without applications of such fertilizer made for the di-
rect benefit of these winter legumes. This is especially
true on lands that have been well fertilized for preced-
ing crops. But when winter legumes are to be planted
on land that has not been well fertilized for other crops,
it is highly desirable that a broadcast application of
400 pounds of acid phosphate or basic slag be made for
the specific effect on the cover crops. On the other
hand, on most of the heavy soils of the upper half of
the State, especially those of the Piedmont, Appalachian
Plateau, and Limestone Valleys and Uplands, phos-
phatic fertilizers are much more likely to be needed.
An application of 400 pounds per acre of acid phos-
phate or basic slag may mean the difference between
success and failure on soils of this kind.
* Those who wish to have their soils tested should write to
the Department of Agronomy at Auburn, or apply to their
county agent, for printed instructions to guide them in col-
iecting soil samples. After collecting samples in accordance
with the instructions, they should be sent to the Department
of Agronomy by parcel post or prepaid express. No sample
will be tested unless it is collected according to instructions.
13
Bur clover is more in need of phosphatic fertilizers:
than any other of the winter legumes. In the light of
experiments conducted in recent years, it is now known
that many bur clover failures have been due to a de-
ficiency. of available phosphorus. Consequently, liber-
al applications of acid phosphate or basic slag should
be made for bur clover unless it is planted on land that
has been very well fertilized for preceding crops.
Time of Planting.-Best results are obtained with
either of the crops under consideration when the plant-
ing is done sufficiently early to secure 
a good "plant"
and thorough inoculation before cold weather begins.
In the northern part of Alabama, 
planting should.
be done between the 15th of September 
and the 10th
or 15th of October if moisture conditions 
permit.
Plantings made as late 
as the latter part of October 
or
the early part of November 
may succeed in mild win-
ters, although a heavy crop is not likely 
to result front
such late planting.
In the southern part of Alabama, 
planting should be
done between the first and the last of October if suit-
able moisture conditions are obtained during this per-
iod. Plantings made as late as the middle 
of Novem-
ber may succeed in the extreme southern 
part of Ala-
bama, but there is considerable risk involved when
these crops are planted this late.
Methods of Planting.-Seed of vetch, crimson clover,
and yellow melilotus are commonly sown broadcast
without any special preparation of the land. 
Either
clean cultivated cotton middles, corn middles, or 
stub-
ble land is a satisfactory place for planting these 
crops.
Vetch seed may be covered with a disk harrow, sweep,
scrape, or spring tooth cultivator, covering the seed
half inch to an inch in depth. The small seed of crim-
son clover and yellow melilotus should not be covered
deeper than about half an inch. Very satisfactory re-
sults have been obtained from open furrow plantings
of bur clover. Small furrows 12 to 18 inches apart are
opened by means of a shovel or scooter, and the seed
sown in these furrows; the seed may be left uncovered
or very lightly covered. If the covering is done with
a light application of well rotted stable manure, a suc-
cessful crop almost invariably results. Another method
is to thoroughly disk the land and sow bur clover seed
broadcast, covering with a drag harrow or cultipacker
14
Rate of Seeding.-The usual rate 
of seeding vetch,
-crimson clover, and 
yellow melilotus varies 
from 16
to 20 pounds. It is advisable 
to seed at the heavier 
rate
when these are being planted 
for the first time. After
the soil has been thoroughly 
inoculated, the lighter rate
is satisfactory for crimson 
clover and yellow melilotus,
but it is best to sow vetch seed at the 
rate of 20 pounds
per acre under all conditions.
It is almost impossible to secure 
a good stand of bur
clover the first year unless very 
large amounts of seed
are sown. The most practical 
way to start this crop
is to sow the seed in the bur at 
the rate of 30 or 40
pounds per acre, and, from 
the thin stand thus se-
cured, grow on the land a sufficient 
amount of seed to
insure a good stand the next 
season. The seed crop
will normally mature about the middle of May, 
after
which the land may be prepared and planted 
to any
crop that is suitable for planting at this date.
Seed Production on the Farm.'-Vetch is the poorest
seed producer of the four crops being considered. 
Con-
sequently it is not feasible to produce a home 
grown
supply of vetch seed; and the 
relatively high cost of
seed is the chief objection to this crop. Crimson clover
is a fairly good seed producer, but the seed are 
not
easily harvested. By means of a seed stripper seed 
may
be harvested satisfactorily on a small scale, provided
the clover is almost entirely free from weeds. A
stripping machine may be made by 
any farmer who
can handle tools well.* Another method of harvesting
crimson clover seed is to cut the crop with a mower
just as the seed are full ripe, and thresh the seed with
a common grain threshing machine.
One of the most desirable qualities of annual yellow
melilotus is its ability to produce seed under Alabama
conditions; and the ease with which the seed may be
harvested. The method of harvesting the seed is simple.
When most of the seed are ripe the crop is cut with a
grain binder and the seed threshed with a grain
thresher from which most of the concaves have
been removed. While there are no exact records of
the amount of seed that may be made on an acre of
land, there are indications that 600 to 1000 pounds per
acre are possible ields. A simple calculation will show
*Blue prints and instructions for making a seed stripper
maybe had from the Department of Agricultural Engineering
at Auburn.
15
that the seed needed for 
a large farm may be harvested"
at an expense of a relatively 
few hours of labor.
Bur clover also produces large 
amounts of seed, but
there is no satisfactory method 
for harvesting the seed
on a large scale. Usually the 
vines are raked off the
field as soon as the crop is fully 
ripe, and the shattered
burs collected by means of stiff brooms.
Reseeding.-Crimson clover will not reseed even
though a full crop of seed is allowed 
to mature on the
land. Vetch will usually reseed 
itself, but no very sat-
isfactory procedure has been worked 
out for handling
the crop so as to insure reseeding. 
Very little is known
of the ability of yellow melilotus 
to reseed the land, but
it is believed by those who have 
had most experience
with this crop, that it will reseed if a full crop 
of seed
is ripened and left on the ground where 
it was grown.
After a full crop of bur clover seed has been 
pro-
duced on an area, reseeding should not be necessary if
the land is properly handled. Bur 
clover produces a
high percentage of hard seed and it is necessary to
grow a seed crop only every other year, or possibly
every third year, to insure a stand each year. Corn or
some other crop that may be planted after the middle-
of May should be planted after the seed are ripe. The
following spring the bur clover may be turned under
as green manure for cotton before any seed are ripe,
since the hard seed present insures a stand the follow-
ing fall as explained above. This being true, 
bur
clover fits well into a two year rotation of cotton and
corn, the seed supply for the two years period being
matured on the land before corn is planted.
Soil Adaptation.-Vetch is adapted to a wider range
of soils than either crimson clover or bur clover. It
has been grown successfully on almost every impor-
tant soil type in Alabama. Poorest crops have been
obtained on thin sandy soil infested with root knot.
Crimson clover has a fairly wide soil adaptation but it
is not well adapted to very poor land of any character,
especially poor, sandy soils. Bur clover has made its
best showing on relatively heavy soils. Gray sandy
soils over yellow subsoils of the Coastal Plain have
produced rather poor crops of bur clover, and it is
doubtful if this crop will give satisfactory results on
soils of this character. Good crops of annual yellow
melilotus have been produced on many different types.
16
,of soil, especially when lime was 
used as a part of the
:soil treatment. The experimental 
results obtained in-
dicate that it may be grown 
on most Alabama soil
types, provided lime is applied 
where it has been found
to be needed. Since it is relatively free from disease
and root knot troubles, yellow 
melilotus appears to be
especially well adapted to the sandy soils 
of the south-
ern part of Alabama.
Use as Hay Crops.-Bur clover should not be con-
:sidered as a hay crop under 
normal conditions. Vetch
and crimson clover have been tested many times as
hay crops in the experiments 
at Auburn. In the ex-
periments of 1921, vetch planted 
alone produced 3953
pounds per acre, while oats and vetch 
mixed produced
3568 pounds of hay. Crimson 
clover, in the same ex-
periments, produced 3360 pounds 
of hay. Corn planted
-on this land after the hay crop was harvested produced
the following yields:
Bushels
Corn on land idle in winter 28.4
Corn after vetch 36.6
Corn after vetch and oats 32.1
Corn after crimson clover 40.0
The land that produced no winter crop yielded only
28.4 bushels of corn, while the land that produced hay
at the rate of more than a ton and a half per acre ac-
tually made more corn than did the area that was idle
during the winter. The increase in corn yields follow-
ing the legume hay crop is attributed to the nitrogen
left in the roots and stubble when the hay was cut and
taken off the land.
Farmers who are intei'ested in the use of legumes
for soil improvement should remember that at least 90
per cent of the nitrogen contained in a crop of vetch,
or other similar crop, is in the part of the plant above
the ground, and that if the crop is cut for hay not mor.
than 20 per cent of the nitrogen contained in the
entire plant is left on the land in the roots and stubble.
Therefore, it is necessary to turn under the entire
growth of such crops in order to get the full benefit of
cover crops planted for soil improvement.
IMPORTANCE OF INOCULATION
Many winter cover crops fail because of a lack of
proper inoculation. When planted for the first time,
17
:and on land not already inoculated, the utmost care
should be taken to insure thorough inoculation.
Method of Inoculation.-Inoculation may be se-
cured by one of two common methods. 
Commercial
cultures may be bought at a nominal price, if 
inocu-
lated soil is not available. When such cultures are
used, the printed instructions on the container 
should
be followed very carefully.
Well inoculated soil is usually surer and cheaper
than bought cultures: Soil for inoculation purposes
should be collected and air dried. At planting time
the seed to be inoculated should be thoroughly mois-
tened with water that is well sweetened with sorghum
or sugar cane syrup, after which the dry soil should
be dusted over the seed and thoroughly mixed. A suf-
ficient amount of the dry soil should be sown very
early in the morning or late in the afternoon; or, better
still, the sowing may be done on a cloudy day. In
either case the seed should be covered immediately, as
a few minutes of strong light will kill the bacteria ap-
plied to the seed. When unhulled bur clover seed are
sown artificial inoculation is unnecessary because a
sufficient amount of inoculation adheres to the burs, or
is carried in the dirt and trash accompanying the seed.
TIME TO TURN UNDER COVER CROPS
Legumes planted for soil building purposes should
not be turned under too early. Either of the cover
crops discussed in this circular will make its most
rapid growth between the 20th of March and the last
of April. It is necessary, therefore, to leave the crop
on the land until it has had time to make a growth
sufficient to justify its use. In central Alabama this
stage is reached between the 10th and the 20th of April,
under average conditions. The data collected by the
Experiment Station indicate that a sufficient growth 
of
vetch or crimson clover may be produced by this time
to contain 40 to 60 pounds of nitrogen per acre.
PLANTING COTTON OR CORN AFTER A COVER CROP
It is somewhat risky to plant cotton immediately 
af-
ter a heavy cover crop has been turned under, 
since
the rotting green manure may cause the seed to 
rot
also. It is safest, therefore, to allow at least ten days
to elapse between the turning of the green manure and
18
the planting of the cotton seed. However, a number
of farmers who are turning under green manure 
crops
each year are planting cotton immediately after 
plow-
ing under the cover crops, and have had 
reasonably
good success in securing stands.
The stand of corn may be seriously injured by bud
worms, if corn is planted immediately after a green
manure crop is turned under. This trouble may 
be
avoided if planting is delayed about three 
weeks after
plowing under the cover crop. It should be stated 
that
bud worm injury is not very common and 
those who
care to take the slight risk of having to replant 
should
plant corn as soon as convenient after 
turning under a
green manure crop. If serious bud 
worm injury de-
velops, the crop should be plowed up 
and replanted.