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Iillet illin No. IS N 'ew ,riWs l i'irIiryv. 1929 a
Soil Improving Crops
g" JOHN M. SCOTT
State of Florida
Department of Agriculture
NAT IAN MAYO. Commissioner
r' l paredl and J'iblishid in Co-operation witli tlh (Collue1 oft
A' uriclt ate. 'i tY of Florida. G isil.
I/ _--._ -- --^_ t
I)EI',AwrTmE'NT OF' ACR1('It I C MTItIIE
Nat han Mayo. (Comm issioier of Agriviillture'
1'. .1. Brooks. I)irector. IBuirea;ui of I mm igrat ion
Phjiil S. 'Iylor, Suipervi sinmg 11 Qto l .)..)............ ..I
Johnim AI. S(.ott, Ag-ricmmhI mral Ediior
(Fa in tsvii I
Soil Improving Crops
By JOHN M. SCOTT
Prepared and' Published in Co-operation with the College of Agriculture,
University of Florida, Gainesville
P ERHAPS no phase of agriculture is of more importance to
the pr.oslective farmers of Florida, as well as the ones
already here, than that of growing soil-improving crops.
It makes little difference whether one is a citrus grower, truck
grower, potato grower, or a general farmer in Florida, for the
growing of soil-improving crops is about as important to each
one as the growing of any other crop.
Soil-improving crops are, of course, just as important in
many other States as in Florida, for a very large percentage of
the agricultural lands of the United States is depleted of soil
fertility each year by crops. This is quite natural and cannot
he helped, although it is possible and practical to grow soil-
improving crops that, when turned under, will improve tile
fertility of the soil.
Florida is blessed with a number of soil-improving crops that
fit in well with farming operations. A legume always makes
the best soil-improving crop, and there are a number grown in
Florida, all of which are annuals and therefore fit into a crop
rotation much better than perennials.
Soil-improving crops increase the humus of the soil, which
in turn increases the water-holding capacity of the soil, often
an important factor in the growth of a crop. The experience
of most successful farmers has been that thi best crops are
produced on those soils that are well supplied with humus.
The virgin hammock soil of Florida is an excellent example
of land well filled with humus. Very little of the high pine
land contains a sufficient amount of humus for the best growth
and production of crops.
Another reason for growing soil-improving crops is that
when a liberal amount of humus is added from year to year,
the soil is kept supplied with bacterial life. which is very essen-
tial to plant growth. A sandy soil on which clean culture is
practiced does not respond to fertilizers as well as a soil of the
same type to which a soil-improving crop has been added.
Soil without abundant bacterial life never responds to fertilizer
or cultivation to the same extent as does soil that is well sup-
plied with bacteria. Bacterial life in a soil is not only de-
pendent upon the humus content of the soil but also upon the
moisture and acid content.
DElPAlTMA1ENT OF AGRICUILTUJJRE
In other words, it one is to have an abundant supply of bac-
terial life in the soil. it is necessary to have a good supply of
both humus and moisture. However, as the humus content of
the soil is increased, the water-holding capacity of the soil is
also increased. These are two very important factors in the
production of a crop. In many cases moisture is the limiting
factor in the production of a maximum crop.
In addition to the humus that the soil-improving crop may
add. it also adds plant food to the soil. The legume crops, of
course, add more plant food than do the non-legumes.
Since warmth and cultivation tend to destroy or burn out
the humus from the soil faster than any other factor, another
advantage of a cover crop is that it keeps the ground shaded
during the summer and thus conserves the humus content.
On sandy soils, especially where there is a sandy subsoil, it
is necessary to grow a soil-improving crop each year, as such
soils do not retain humus or nitrogen very long. However, on
the clay soils, or where there is a clay subsoil, there is not so
much leaching of the nitrogen or burning out of the humus.
In other words, in the clay soils the results of a soil-inmproving
crop are more lasting.
The growing of soil-improving crops will not take the place
of all commercial fertilizer necessary to produce maximum
crops, but it will materially reduce the amount of commercial
fertilizer needed, and it will put the soil in such condition that
the crops grown will utilize tlhe commercial fertilizer that is
applied to better advantage. As maximum crops are usually
the most economical to produce, every effort should be made
to keep the land in such condition that best results will always
be obtained so far as crop production is concerned.
CHOICE OF SOIL-IMPROVING CROPS
The choice of a soil-improving crop will depend largely upon
the preference of the individual person and the character of
his soil. There are a number of legume soil-improving crops
that are desirable for most conditions in Florida. The legumes
that have generally given the most satisfactory results are
velvet beans, cowpeas, beggarweed, crotalaria, vetch, pigeon
peas an( Austrian winter pea. In addition to the legumes, one
has tlhe choice of a number of non-legumes, such as crab
grass, Natal grass, sand burs. Mlexican clover (which is not a
legume'. and other grasses and weeds that might grow.
Soil, I.MPR\l'VIN(; ('HI'M S
There is nIo de(linite information as to tIie exact date tilhe
velvet libean was intro(duIced into Florida. The name velvet
bean appears toi have been applied to the plihnt for the first
time by the Florida Ii lxperimeii Station in 11ulletin No. 35
(18!) ). illh ltnLo'h it ihad been rowln ill thli State several years
prior to this. T'lhis variety has lbeein called Florida Velvet Bean
ever silce that tillle.
As late as 1907 there was oily on(e variety of velvet beain
known to sotliheastern 'llnited Sitates. Tha' was the Florihda
velvet hean. Sinee that time other varieties have been intro-
tuced into the United States by tlie liureau of Plant Industry
of the I'nited States l)Deparltiient of A,,ricullture. In addition
to these introductions. the Florida Experiumient Station and tilhe
Bureau of Plant Industhry have developed iew varieties by
crossinli somen of the iiimportedl varielieis.
The varieties now grown ill tle State are Florida velvet.
Lyon, velvet. ('hinies. velvet. (;orgia or early speckled velvet.
and Osceola velvet. There are oilier varieties, but those given
above are tlie best known and more generally grown.
The velvet heall is a long seasoll crop; by this is meaInt, lhat
it grows from early spring until killed by frost in tlie fall.
How to Plant
Every grower has his own metllod of planting. 1H however,
best results will be ohtainled hvy pinitiig i rows 'roiu th iree
to four feet apart and droppii.,u the seed eighteen to twenty-
four iindhes apart in the row. It may lie possible to increase
tlie yield of foliage by planting, i in rows six or seven feet apart
and between the rows of helis plant corin io sorghu mln. Tlhe
eorni oMr sorg liiu11 will for'l' a Il'lis uponl whvlich Ihe heans
When planted with (olrn or sor.gh'iiii. aboll one peek of
velvet, bean seed is required to phlal an a1re. Ift planted alone,
it will take about one-half bushel of seed to plant an aire. One
bushel of seed weighs i6 pounds.
When to Plant
Since tle velvet blleai is sensitive to onhl. there is no great
hurry about plantiuig early ill tlie spring. In f'at. velvet beans
will grow olt quicker and make a iiiore satisfactory growth if
they are inot planted until the grou1nmd lias become thoroughly
Fig, 1, Florldi Be BeVSos growlrg is i soil Improving crop. Courtesy Fli. Ept, SttIon,
SOIL IMPROVING CROPS 7
warmi so that they will not le checked in their growth. Satis-
factory results wil! ordinarily he obtained by planting any time
in April or early in May. In the southern part of State, plant-
ing mIay be made in February or March.
Preparation of Seedbed
The land is prepared about the samei as for corn or cotton.
The ground is first plowed Ibroadcast about four to six inches
(leep. i" there is not a great deal of vegetation on the ground,
the land may be prepared with the disk harrow. It ma*y be
necessary to doubl'e-disk the ground in order to put it in good
It will pay to cultivate the crop at least twice. for this will
lend to hasten the growth of the young plants and at the same
time keep down weed growth. As soon as the plants begin
to put out vines, they will cover the ground so as to keep down
all weed growth.
The yield of green material per acre of velvet beans will
vary from1 four to five tons up to ten or fifteen tons, depending
upon the character of the soil.
Flg. 2, Chitese Vedvet BeROS growing H8 1 s$i0 ImprOVig crOp, Courtesy F18. Expt, Station.
8011 IMLPR()OVING 'ROI'S
Fig. 3. Nitrogen nodules on roots of Velvet Bean. Courtesy Fla. Expt.
I In, W-
10 DEPARTMENT OF' AGRICULTURE
YIELD AND ANALYSIS OF VELVET BEANS IN ALABAMA,
LOUISIANA AND FLORIDA*
Ala. La. Fla.
Pounds Pounds Pounds
Weight of green material from an acre............ 19,040 22.919 21.132
Weight of dried material from an acre........ 8.2.10 7,495 5,953
Weight of dried roots from an acre ................ 1,25 191 690
Weight of nitrogen !n vines from an acre .... 201.3 170 131.5
Weight of nitrogen in roots from an acre ........ 12.6 2.9 9.7
Total nitrogen in crop from one acre .......... 213.9 172.9 1-11.2
Fl;. IExp> riment Slaitlon Hulletin No. 60:456: 1902.
('Cowpeas is another annual legume that grows to perfection
in all )parts of Florida. It is a crop thal matures in from 65
to 90 days. depending u1pon conditions adl the variety, and
nma., therefore, he termed a short season erop. This makes it
well adapted to planting after a late spring or summer vege-
There are a large number of varieties of cowpeas suitable
to Florida. During the past twenty years the Florida Experi-
menl t Station has tested more than one hundred varieties, but
at the present time the Brabliam anid Iro varieties are best for
Florida conditions. Both of lhese varieties are more or less
vining in habit of' growth. C(owpeas, however. do not make
as mnii(h growth of vines as do velvet beans.
The Brabham and Tron varieties are more resistant to root
knot and( wilt than any other varieties, and this is an important
feature in Florida.
Preparation of Seedbed
The preparation of the seedbled for cowpeas is the same as
for velvet beans. The ground should he disked or plowed
thoroughly before tle seed are planted.
When to Plant
Since cow\peas are a short seasoll erop, they call be planted
much later in the season than velvet beans and still make a
heavy growth of vines and leaves before fall. There seems
to be no "best tine" for planting cowpeas, as they may be
planned any time from Marh to tthe first of August in South
Florida. from March 15 to July 15 in Central Florida. and from
April 1 to July 1 in North Florida.
Fig Cowpeas planted Bhtmecn corn rows As a soil improviqp crap, Courtesy Fla, Expt, Station,
12 DEPARTMENT OF AGRICULTURE
Cowpeas may he planted alone or as a companion crop. It is
a common practice to plant cowpeas with corn, the cowpeas
usually being planted at the last cultivation of the corn.
How to Plant
The heaviest growth of cowpeas will be produced by planting
in rows two and a half or three feet apart. drilling the seed in
the rows. About three pecks to one bushel of seed will be re-
quired to plant an acre.
The yield of cowlpeas will vary.v depending on the character
of the land and time of planting. From two up to five or six
tons per acre of green material is about the average.
Fig. 5. Cowpeas In a citrus grove growing as a soil improving crop.
SOIL IMPROVING CROPS 13
Another annual legume well adapted to Florida conditions
as a soil-improving crop is beggarweed. Its habit of growth
is quite different from that of velvet beans or cowpcas, as beg-
garweed is an upright growing plant that reaches a height of
four to eight feet. When the stand is thin, the plants branch
freely, but when the stand is thick the plants make a straight,
slender growth with many leaves.
Preparation of Seedbed
The preparation of the seedbed for beggarweed is the same
as for any other crop. The ground must be thoroughly disked
or plowed and then smoothed by the use of a harrow.
How to Plant
Beggarweed is best grown by sowing the seed broadcast.
The seed, which are small and resemble alfalfa seed, should be
sown at the rate of fifteen to twenty pounds to the acre. A
harrow is generally used to cover the seed.
Fig. 6. Beggarweed growing as a soil Improving crop in a citrus grove.
Fig, 7, A heavy growth of beggarweed,
Soil, IMPROVINGCROl)S 1
When to Plant
The best time to sow beggarweed seed is from May 15 to
.1une 20, although under very favorable conditions it mlay be
sown as lalc as July 1 with good results. Beggarweed seed
require a walrm moist soil for best germillatiou and growth,
and nothing is gained by sowing 1too early in tlie season.
If lbeg-arweed is allowed to ripen seed in ilhe fall. it will re-
seed itself and come ulp the following' sprinii. Some people
may get thlie impression that beggarweed will become a pest in
a cultivated field, but there is no danger of this since the young
beggarweed plants are very easily killed by cultivation.
When land that has grown hegg'arweed one season is planted
to corn 1le following season, very little beggarweed is apt to
appear until thlie corn has been laid by,. which is generally the
latter part of .June. By Auu ist or September the chances are
that there will be a fine crop o- f beggarweed to plow under.
Fig. 8, Crolslira ilpicihbilli, lormirly ciItid C. lirocii, used Asi loll improving crop in Tong Oil grovi,
__SOIL ]MI-'ROVIN ('CROPS 17
Crotalaria is a much newer legume to Florida than any of
the ones just mentioned: however, it has been grown here a
number of years and has given such satisfactory results as a
soil-improving crop that it is now grown in all parts of the
Crotalaria is an annual legume that makes an erect growth
three to six feet in height. When the stand is thin the plants
branch freely, but when planted thick the plants make an up-
right growth with few branches and a good percentage of
There are two species that are now generally grown in
Florida. These are Crolalaria, spectabilis, formerly called C.
scricea, and Crotalaria striati. There are other species, but
these two have been so satisfactory that there should be no
question about planting either of them.
Crotalaria may be planted in rows or sown broadcast, but
the larger part of the crop in the State is sown broadcast.
Ten to twenty pounds of good seed will plant an acre, after
which the seed are covered with a light-tooth harrow.
Preparation of Seedbed
The preparation of the seedbed is the same as for beggar-
When to Plant
Crotalaria may be planted any time front March to the
middle of June. When the crop is allowed to mature and ripen
seed in the fall, there will be sufficient seed shattered to reseed
and give a good crop the following spring.
Crotalaria seed may be sown broadcast or drilled between
the rows of corn at the last cultivation, and it will make a
good growth before frost kills it in the fall. In fact, this is
one of the most satisfactory ways to use the crop.
Crotalaria is perhaps the heaviest yielding soil-improving
crop grown in Florida. It is not at all uncommon to get yields
of five to eight tons of green material per acre, while there are
a number of records of eighteen and twenty tons of green ma-
terial per acre. It may, therefore, be said that the yield will
depend very largely upon t te time of planting and local condi-
tions. Under average conditions a yield of six to ten tons of
green material per acre is not too much to expect.
Fi1lvCotIr~ tI~I citri goeo o mrvo rp
Fig, 10, Crotalaria striata growing as a soil improving crop,
h i, :i~ill8.~ 1;
DEiPARTME\ IES )1~ \GRI( I:I ~ R
Fig. 11. Crotalaira striata root system showing nitrogen nodules. Courtesy
Agronomy Dept. Fla. Expt. Station.
Fig. 12. Crotalaria spectabilis, showing Individual plants in bloom and seed
pods. Courtesy U. S. D. A.
SOIL 1.11PIO)VING (IMPS
DEPAIr'MENT OF AGRICULTURE
Fig. 13. Crotalaria striata, showing single plant. Courtesy U. S. D. A.
.., +: +
Fig, 14, Crotilaria spectabilis, formerly called C, sericea, growing as a soil improving crop, This field produced a yield of 26 tons
green material per acre in 198,
l)EPA RTMiENTr (w vaucuuriiiiri .i F
l'i_,.eill pea i a rather ii\. crop,, for FloridaI,. lit a iulnlie.r
ot t ht, inllicate that there is ia good future for this crop in
;ill parts of tli State. This is also .an annual legIumeI that
111;llis It heaI vy growth (Ildrillg thle sulillell(r seasolln nIl od will
ltl(l Il ila e ( lIanllity (it' orgp illic 1111ni 1itt r to tit1 soil. Thert alre
; Ililllb r it' f v\iariit. ie. hill Iot! tiio'litl work has been d' one toi
dl-tt.riiiiin which l ill li, th li miot ,.iti-f.etry for Flirida tl von-
Sinve this is in crop' that makes a rapid growth, it Imeans that
it will lproduce'II a heavy tonllilat of green ninlterial to he r'e-
itrned 1ti tlie soil. Ill firt, ti growth is so li h avy t hat it is
oftenii lifTicult to, ploiw under in thit fall r winter. It miiy I'v
founil aidvisahile to make a cutting (of this
and lihen let it make a second crop that will be ready to turn
under iln the fall o early winlter. Ilandling the crop in this
way will not r'ediicee til total yichl for litl year. buSt it keeps
thlle rp from lie ,oil.inr .4- liare and cumiilbersoe thlat it will
bie lilYiniilt to incorporated with the soil.
If tiht crop is cut in .July -each slinum er. it slihould be cut high
enughli to leave a istulbble ten to twelve inches high, as the
stubble will then sprout out and make a setontd growth.
Preparation of Seedbed
The preparation of thec seedbed for pigeon pen is aiomut the
sile 11 It'sor cowlpeVs or beggarrwied.
When to Plant
As pigeon I).asI are ratilhr sensitive to cold, they should not
he planted( in lhe spring unil danger olf frost is p)ast. Iln the
extrelmie sottlierni part of lthe State. phlatiing may be made al-
mist any time after February 15 up to .Iuly 1. In central
FlHridih. planTing may be made any time from about Miarchi 21
to .June 1. and in north Florida from April 15 to .Jilne 1.
How to Plant
I'laint in rows four to six feet apart and drill tile s.edIl in thl
row. The seed are small so that a peck or peck and a half will
lie sufficient to plilt, an ere.
I'lliltiing, in rows gives chance to (ultivate tlhe crop. This
will haste en til.e gritlW it as well as keep (lown weeds intil the
plants I,-iini-. i-'taiblished and have ihade a gIoid growthi.
Fig, 15, Pigeon peas, This crop produced an immense yield of green material,
- I 'A I
DI)ElAR'I'ENT 0F A(;RICT-LTURE
TABLE I. AVERAGE COMPOSITION OF PIGEON PEA PRODUCTS*
(Based on all available analyses made in Hawaii to February 15. 1920.)
C 2 Caroliohydrats
cl.ini't-r of -tplil -"
"- 3 -.
Fresh green forage..'.. 70.40 2.64 7.11 10.72 7.,S 1.1: 1.65
WholE plant as hay
and groundll Into meal 11.19 3.53 1.1.83 28.7 39.89 2.37 1.72
Seed and pod meal .... 11..15 3 .85 17.65 30.73 34.53 I 2.82 1.49
Seed meal .............. ....... 12.26 3.55 22.34 6.44 53.94 3.57 1.46
Thrashed pod meal .... 1:.30 2.66 8.75 35.44 39.22 1.40 1.0:
Iulletin No. 46. Ifawaii Experiment Station, 1921.
Supper third of plant with s-.td in pold.
S tHy-prHodll(ct I sud prod(luctlOll.
COMPARISON OF SOIL-IMPROVING CROPS
The followiiig tilales give information as to the conipairative
vale11 of a iinl)uliibe of soil-imiprovili. crops. 'The yields given
iare 1 ill tons of InIy per acre. lleretofore inl this I)il!ltin
mention has been Iliade as to the yields in tons of green Iia-
terial. It might l)e well to state that the yield of green Ila-
terial per acre will he about two or two and a half times the
yield of hay.
Table II gives the yield of hlay ill loans of four legumes for
each of three ears. and tile average for the three years., when
gI)ownl at (ainiesville. Florida. The variation in the yieldl of
the legIlllnes is shown to be rather large.
TABLE II. YIELDS OF FOUR LEGUMINOUS CROPS IN TONS OF
AIR-DRY MATERIAL PER ACRE AT GAINESVILLE. FLA.*
Crop 1924 1925 1926 Average
Beggarweed ....... . .. ... 0.79 0.92 0.15 0.62
Velvet Beans ......... ....................... 0.98 0.82 0.76 0.85
Cow pe s ..................... ............ ........ 1..81 1.30 0.52 1.10
Crotalaria ......................................... ....... 2.59 1.90 4.18 2.89
h'lie yield of the same leguntle crops when grown at Lake
Alfred. Florida. is shown in Table III. although at Lake Al-
fretd records of tile yie!d were obtained for only two years. Thie
average' ohl the two years at Lake Alfred is muciih better llian
Tlie tihree-year avieraoge at (ailiesville.
St,,ks. W. E.. .A rolnomist. IFlo )rila Agrictlltullr .l Exiri mlent Station.
,I.l'm ti l ,f th, i .*',i,',n1 ',ritn "f \iiO e vet ,Lt. V\ l. 1:1. N.. In. (ft'i hl-r. !'1'T7.
__ SOIL IMPROVING CROP()S 27
TABLE III. YIELDS OF FOUR LEGUMINOUS CROPS IN TONS OF
AIR-DRY MATERIAL PER ACRE AT LAKE ALFRED, FLA.*
Crop 1925 1926 Average
Beggarweed .................... ... .................... 2.29 1.78 2.03
Velvet Beans ... .......................... .. ........ ..... 1.27 1.53 1.40
Cow pleas .... .. ...................... ..... .......... .. 1.27 1.01 1.14
Crotalaria ....... ...... ......... ............... ..... .......... 2.7( 3.69
Table I V gives the percentage of nitrogen in each of the four
legumIe crops grown.
TABLE IV. PERCENTAGE OF TOTAL NITROGEN (DRY BASIS) IN
CROPS GROWN AT GAINESVILLE, FLA.*
Crop Tops Roots
Beggarweed ...... ............. ..................... 1.64 1.07
V elvet Beans .... ............. ......... ........ ..... 2.51 1.4S
Cowpeas .............. ......... ................. .... 2.29 1.65
C rotalaria ............... .. .................. ... ... .... .................. 2.78 0.92
Tables V and VI show how he yield of corn and sweet pota-
toes was increased when different legume ro)ps were plowed
under in comparison with a non-legume. These two tables are
given here so that an idea may be obtained as to the value of
legumes in increasing the yield of crops.
On a two-year average the legume cover crops plowed under
increased the yield of corn all tle way from 3.7 to S.0 bushels
an acre. Well sweet potatoes were grown. the leglumle cover
crops, when plowed under, increased the yield of potatoes
fromi 9.3 to 27 bushels an acre.
TABLE V.-CORN YIELDS IN BUSHELS PER ACRE FOLLOWING
NON-LEGUMES AND LEGUMES TURNED UNDER *
Non- Velvet Beggar-
Year legume Crotalaria Beans Cowpeas weed
1925 .................. 15.13 21.71 22.99 22.28 19.28
1926 .................... 8.40 17.65 1 .66 12.90 11.75
Average .............. 11.7 19.68 19.82 17.59 15.31
TABLE VI.-SWEET POTATO YIELD IN BUSHELS PER ACRE
FOLLOWING NON-LEGUMES AND LEGUMES TURNED
Non. Velvet Beggar-
Year legume Crotalaria Beans Cowpeas weed
1925 ................. .. 37.50 78.00 54.50 1.00O 55.00
1926 ..................... 26.0 39.72 34.33 33.75 27.19
Average ................ 31.79 538.Si 44.41 -17.37 41.09
The yield of hay per acre, Iercentage of nitrogen in tlhe crop.
and the total pounds of nitrogen produced per acre by each of
the four legumes grown at Gainesville are slown in Table VIT.
A cover crop tlia will add from 17 to 141 pounds of nitrogen
SStO.kes. \V. E., .\Agl'rll"lnis' Fl-' riaI Agriculllr ii l *:xp.i rillln.l St;tioIn.
SIourtH I of th" Atmrirmon Sw it't!f ol .tr'ono iy, V'ol. 11), No. Ill. Oct, ( o lber. 7T.
DEPARTMENT OF AGRICULTURE
per acre each year will, if not leached out by excessive rains,
increase the fertility of the soil from year to year. A farmer
knows from actual experience the value of nitrogen. He knows
that it is the most expensive fertilizer element that lie pur-
TABLE VII.-YIELDS OF HAY FROM FOUR LEGUMES GROWN AT
GAINESVILLE, FLA., AND ESTIMATED AMOUNT OF
NITROGEN IN CROPS PER ACRE
Yields in tons, Percentage of Pounds Nitrogen
Crop 3-year average' Nitrogen: per acre
Beggarweed ...................... 0.62 1.443 17.890
Velvet Beans .................... 0.85 2.208 37.536
Cowpeas ............................ .10 2.015 44.330
Crctalaria .......................... 2.89 2.446 141.378
SeeC Table 1I.
Not only do cover crops plowed under add nitrogen to the
soil, but they will also increase the organic matter in the soil.
Table VITT shows how cover crops, when plowed under, in-
crease both the nitrogen and organic matter in the soil. The
results shown in Table VIII were not secured in Florida, it is
true, but the test was carried on at Cairo, Georgia, on Norfolk
fine sandy loam. Since there are hundreds of acres of Norfolk
fine sandy loam soil in Florida, the results obtained in Georgia
are applicable to Florida soil of this same type. If such results
can be obtained on Norfolk fine sandy loam, it is reasonable to
expect similar results on any good soil throughout Florida.
Table VII brings out the fact that the results obtained in
Georgia by plowing under the cover crops, all of which were
not legumes, indicate that the percentage of organic matter in
the soil was more than doubled in five years, and tlie nitrogen
content was also doubled.
TABLE VIII.-ANALYSIS OF SOIL FROM A PECAN ORCHARD ON
NORFOLK FINE SANDY LOAM AT CAIRO, GEORGIA, ON
WHICH COVER CROPS WERE GROWN AT DIF-
FERENT SEASONS OF THE YEAR*
Spring and Constituent
Summer Cover Fall and Winter Constituents
Year Crop Cover Crop Organic
1918 Fallow.................. Bur Clover .......................... 0.64 0.031
1919 Cowpeas.............. 'Oats .....................................
1920 Beggarw eed .........! R ye ..........................................
1921 I Cow peas...............! Rye ..................................... 0.90 0.040
1922 | Velvet Beans....... Rye and Oats ....................... 1.23 0.050
1923 j Velvet Beans.......! Rye and Oats .......................... 1.39 j 0.061
U. S. D. A. Department Bulletin No. 1378, p. 4-5.
SOIL IMPROVING CROPS 29
Organic matter and nitrogen are two very important factors
to have in the soil, and it is to the advantage of every farmer
to sec that the percentage of these two constituents is kept as
high as possible in all of his land.
Table IX shows how the water-holding capacity of the soil
is increased when organic matter is added. The table shows
that when 5 percent of organic matter is added to coarse sand,
the waterholding capacity is increased 40 percent. When 10
percent of organic matter is added, the water-holding capacity
is increased 85.7 percent.
TABLE IX.-EFFECT OF ORGANIC MATTER ON RETENTION OF
MOISTURE IN SAND*
Soil Material water retained Increase
by 100 grams percent
Coarse Sand ........................... ................. 13.3
Coarse Sand with 5 per cent Peat .................... 18.6 40.0
Coarse Sand with 10 per cent Peat .................... 24.7 85.7
Coarse Sand with 20 per cent Peat .................... 40.0 200.7
Peat ............................................. ............................ 184.0 1283.4
Sa il I'I/hysivi and .lanagcr ii( n t, by .1. (. Mosier and A. 1.'. (U;ustafson, p. 119.
The question is often asked, "What is the actual value in
dollars and cents of legume crop when used as a soil im-
prover?" This will depend entirely upon the yield of green
material that can be produced. The value as a soil improver
or as a fertilizer may be stated about as follows:
The nitrogen content of the green material is about seven
tenths of one per cent, or, in other words, each ton of green
material contains about 14 pounds of nitrogen, which is equiva-
lent to about 100 pounds of nitrate of soda. To put it another
way, each ton of green material produced per acre is equivalent
to the nitrogen in 100 pounds of nitrate of soda. If the yield
of green material produced is four tons, then it would contain
as much nitrogen as 400 pounds of nitrate of soda.
There is a difference in the form of nitrogen produced by a
soil-improving crop and that in nitrate of soda. The nitrogen
in nitrate of soda is very quickly available to the crop to which
it is applied, while nitrogen supplied by a soil-improving crop
is not nearly so quickly available for use by the growing crop.
For this reason it is often necessary to also give the growing
crop an application of commercial fertilizer containing nitrogen
in a quickly available form. This is especially true when a
short seasoned or quickly maturing crop is being grown. Corn
following winter legumes will need no fertilizer.
'i I'll, fd i lltl 2 Iaref I'' lltt (i' til willtel- IvL'.ZI1tn1.. that a' L. III...i
11 oil lit' t lif- NI at v w ilel -v Nv \\ill t 4.1. 11evil I lw, va lilt- I t I.\
at I iii hiis l t I I I I It lit I'idg tv s avi i 111 t 4r.i L ll-val. it I-il l' ill,,s v
111tI I~- In. sill al L miiill usa! ii \\.i~i"S hsht.hlt a'.sitW~tlZV
When to Plant
lIl~tii' \(etehil tIit' lic pl~anrtedi Ill.\. 11114. fri111 1hI lttihuer Io Dc-
(14111111(.1:. I'laittiigs ill Nmulli anu \Vest Fltilda uay he tioih
1*ll'livrl Ill Illv fa'ill 111,111 ill S()Ill1 F1 I fI a Sill e Ila i-v i
a \ I I cl ql1 f 1.1. it 1, 11 it \v I #- I ( 11), ;1 itI to )I ea 1.1 11 1 1 It-, a l I~ ,1 I1'
I h at art. I I 1 4.1 11 v I i i IIt I I \v a I- Ill. F I. I I ,'., I-ea .Iills lilt-
Preparation of Seedbed
Tlw cX r 1f.1,10.111... (11, .1 1II I,'I I~f ha, \\'I\ 1; i t.1' ll dial 11.
Il11Ii.. prepar;l.;ti''ll ()f Ow NO-1.(1(/1111-d is 14211? fill- velv1(J. I f
Iini is It. Ii4JlV v iri'.Vtll I)I1 tIn tt.ll( Itd. tl sdt Illalv beu' sim\-
Ill-mllic;I' h ;111 11uhv ('4iio.-'l-e \\.itlt II li a .l ht' m 'l,'. 11111 suu 1114u the
..ru''' It i ll., landl b1. 'ivIIit, a Illlilt 1t*0 I(4 \\.Ithi ll V. n..rw tllh
-1-41111141I is 411,14,11 lievs-sanl.! I, to 1)11 1 it -ml~ id~ cm)~(liticoll afte1I'1
How to Plant
Ilair'. \iti i sie hl iihul Itl smv.'ii h l(ittihiitst st I I i s a n e oit 20(
Ii s1) ::0Imiiiil'. i4f mtel to theil- ar. atter h tiielt the sveil shtithil
!- -1--1 \\ilt ;Ii il i'.I hait'* i.
DI-'I'ART.N1EN'I' (IF A(;RICFITI'kE
Fig.1 Austrian winter peo left, hairy vetOh center, Monanthi veth right,
Fig, 17, Hairy vetch In pecan grove, grown as a soil Improver, Courtesy Agronomy Dept, Fla, Expt, Station
The yield of \v'I!I i., not its nititie as for s lll' so te the- summiler
Ieguiiics, 1)1bu thle Nic(I1 is slhffiviit to wariaiiill )Ipailtilig if the
Iigh1t I, yje of soil is selvtted.
Thel vichI of irreeli materials 1,1Na Varl-1rolm t hree to five tolls
per1i(lI. 10h ile llItT fbilvora'blel conldlitionlls itYield of eight t
It'll to!l,' (it, zl*((.l material p~ er e Oll'. h e exjieeted. `iiehls of
as hiitrli as' twlvei 1e 111N per actle h1;1e beeni reported several
tililes ill l'loriula
'flie haiamlliti ofthlisi ii op is the same as for hairy veteci.
AUSTRIAN WINTER PEA
Atist'.T a w1 ilnter pIva i. aniotlhier winter jrlellnne thall vlai bo
!'It'ox-ui sat ist Isfactolrl.. especialiv thlrulvl North and;Il \\est
Florid. 1Fr10m01 1() 35 pou n)oiids Id sl il(ld sIeda. qliuireld forI all
Soil p~reptaration,. seevling. aind timne of Jplawnlog are tile( salil
as It for veli.
SMI, 1,1111MVING' CIMPS
Fig, 18, Austrian Winter Peas, Seeded Octobe, 1928; photo taken January, 1929
SoIll li\Ll1ROV1N(G (M'l)S
In planting Austrian winter peas, hairy vetch. and Monantha
vetch for the first time in a field, it is very important that the
seed be inoculated before sowing. It is not necessary to inocu-
late velvet beans, cs, o erotalaria, or be''ggarweed seed.
It is neither difficult nor expensive to inoculate. The inocu-
lating material can generally be purchased with the seed. or it
may be obtained front any reliable seed house. If the seed are
not inoculated, the chances are that a very unsatisfactory
growth of these legumes will be obtained, which may mean
that the crop will be considered of no value and discarded. It
will also be found that a m1uch better crop will be produced the
second and third year than was produced the first. It is. there-
fore, advisable to plant these legumes on tlhe same land each
year for two or three years, for in this wayi tlie soil becomes
thoroughly inoculated and as a result much better crops are
Instructions as to how to inoculate always come with tlhe
material whenI purchased.
In addition to artificial inoculation, good results may also
be obtained by using soil from a field that has grown two or
more successive crops of well inoculated vetch or Austrian peas.
The growing of soil-improving crops is one problem, and
plowing them under so they will Ieconme part of the soil is
quite another problem. In the past it has been rather difficult
to get farmers in Florida to grow soil-imlproving erops largely
because it was not an easy matter to plow them under. To
plow under a heavy crop requires good machinery and plenty
of horse power. An ordinary 12- or 14-inch plow will not do
the work satisfactorily.
About the best way to do the job is to first go over the field
with a heavy disk harrow, a double disk being the most satis-
factory. In many cases it is necessary to weigh down tle disk
with two or three sacks of sand.
There is some question as to tlie best time to plow under a
soil-improving crop. Some farmers advocate doing tlie disking,
in November or December, while other suggest that it is better
not to disk until just previous to planting the spring crop.
The ideal way would be to disk down tlie crop the latter
part of September or early in October, and plant the land to
vetlch or Austrian winter peas. Then the vetch or Austrian
Fig. 19, Disking under crotal8ria, Jaritary, 1929,
peas should be turned under ten days or two weeks before
Planting the spring crop.
If no spring crop is to he planted. it will he found a good
plan to break down the heavy sinnmer growth any time from
November to .January and let it remain on the surface of the
soil, provided there is no danger of fire. Should there be
danger of fire, it is desirable to go over the field once or twice
with a disk harrow so as to do away with tle fire hazard.
When Austrian winter peas, vetch, oats. or rye are grown
during the wilnter season, they should be allowed to grow until
about two weeks before the spring crop is to be planted. They
an then either le plowed under or disked in with a good disk
harrow. When these crops are grown on land that will not
be planted to an early spring erop, they should be allowed to
grow as late as possible in tlie spring so as to have as mulch
organic mnatteri as possible to add to the soil. As the warm
spring weather approaches, tle Austrian winter pea and
vetches will cease growing. It is desirable to turn them under
just before this stage is reached. Oats and rye should be
turned under before they begin to show seed heads.
SOIL IMPROVING CROPS