Sudan grass

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Issued June 16, 1919.

UNITED STATES DEPARTMENT OF AGRICULTURE,

Department Circular 50.

Dureau”’of Plant Industry,

(New and Rare Seed Distribution),
WM. A. TAYLOR, Chief.

SUDAN GRASS (Andropogon sorghum var.).

OBJECT OF THE DISTRIBUTION.—The distribution of new and rare seeds has for
its object the dissemination of new and rare crops, improved strains of staple
erops, and high-grade seed of crops new to sections where the data of the de-
partment indicate such crops to be of considerable promise. Each package con-
tains a sufficient quantity for a preliminary trial, and where it is at all practi-
eable the recipient is urged to use the seed for the production of stocks for
future plantings. It is believed that if this practice is followed consistently, it
will result in a material improvement in the crops of the country. Please make
a full report on the inclosed blank regarding the results you obtain with the seed.

HISTORY.

This grass is an annual belonging to the sorghum family. It was
secured from Khartum, Sudan, in 1909, as the result of a search for
the natural forms of Andropogon intermediate between the culti-
vated sorghums and Johnson grass. In leaf, stem, and seed char-
acters Sudan grass resembles Johnson grass very closely, but it lacks
the underground stems, or rootstocks, which make Johnson grass
difficult to eradicate. In root characters Sudan grass is more like the
sorghums, and by several investigators it is thought to be the wild
form of the common sorghums.

DESCRIPTION,

When planted in rows and cultivated on fairly rich soil, it grows
to a height of 7 to 9 feet and has stems one-fourth of an inch in diam-
eter. Broadcasted it rarely exceeds 3 to 5 feet in height and the
stems are much finer, one-eighth of an inch or less in diameter. The
seed head is loose and open, like that of Johnson grass. The hulls,
or glumes, are awned when in flower and often purplish in color at
that time. When ripe there are both straw-colored and black seeds,
and most of the awns are broken off in thrashing. The seed itself

when thrashed closely resembles Johnson grass seed, except that it
121235°—19

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is a larger and well-matured seed and has a greater percentage of
hulled seed’ in it. In general, however, it can only be distinguished
from Johnson grass seed by the close scrutiny of a seed expert, and
therein lies, perhaps, the greatest danger in the use of Sudan grass
by the American farmer. Unscrupulous seedsmen will find it easy
to adulterate it with Johnson grass seed. This danger, however, will
be present for only a few years, as it is much easier and cheaper to
produce Sudan grass seed than that of Johnson grass. The danger
of the future will come about in the use of Sudan grass seed pro-
duced on land infested with Johnson grass, thus bringing about a
natural admixture of the seed.

CLIMATE AND SOIL REQUIREMENTS.

Sudan grass is not particular about the soil, but it does best in a
fairly rich clay loam. In sandy or poor soils the growth is rather
weak and the yields low. Belonging to the sorghum family, it shares
with the rest of this group the preference for a warm growing season.
Tt will stand slight frosts, but continued cool weather interferes
with its normal development, and this fact prevents its success in
high altitudes. It is fully as drought resistant as the ordinary culti-
vated sorghums, and when grown in rows and given similar cultiva-
tion it can be relied upon to produce a crop of hay with very little
rainfall. It has a short growing season, maturing for hay in about
75 or 80 days and for seed in from 100 to 106 days from seeding
time if the weather is warm. This quality allows of its use as a
catch crop throughout the corn belt and extends its territorial mit
north in the Great Plains region to the north line of South Dakota
and a like distance in all other regions characterized by hot summers.
Excessive humidity, such as is found in the Gulf coast region, is .
injurious to Sudan grass, because it induces red-spot and other dis-
eases which make its growth unprofitable. Disease-resistant strains
are being developed to overcome this weakness. j

SEEDING.

Sudan grass should not be planted until the soil has become warm
in the spring. Planting in cold soil only delays germination and
dwarfs the early growth. It can be sown any time during the
summer as a catch crop, so long as 70 to 80 days intervene before
the date of the first expected frost. Sudan grass can be sown in
rows 18 to 42 inches apart and cultivated like corn, or it can be
drilled in with a grain drill or sown broadcast by hand. In the
semiarid sections it is much more profitable to seed it in rows and
cultivate, and even in the huzaid regions a small amount of cultiva-
tion appears to give added vigor to the plants. The rows should

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™ be as close er ee as the tools available for cultivation will permit.
‘s Where sugar-beet cultivators are at hand 18 to 24 inch rows are best,

‘\™ but in most cases the farmer will find it more convenient to place the

‘S rows 36 to 42 inches apart, so that he can use his corn cultivator.
Seeded in rows 36 to 42 inches apart, 2 to 3 pounds of good seed to
an acre are sufficient. In rows 18 to 24 inches apart, 4 to 6 pounds,
and drilled or broadcast 16 to 24 pounds per acre are required,
according to the rainfall.

HARVESTING.

Sudan grass is easy to cut with a mower and cures readily, so
that the haying process is much the same as that of millet or any
other hay grass. Where it is harvested for seed, an ordinary grain
binder is best suited for handling the crop. When cut for hay, it
is best to cut it just after full bloom, so that it will have as much
time as possible for the second growth. After cutting, it renews
its growth promptly when moisture conditions are favorable, and in
about 40 to 50 days another cutting is ready. The grass stools
abundantly after the first cutting, and the second and third cuttings
are very fine stemmed. In 1912 four cuttings were secured at Chilli-
cothe, Tex. Ordinarily two or three cuttings may be expected from
the central United States southward, and one cutting north of the
middle.

UTILIZATION.

Sudan grass makes a very nutritious and palatable hay, which is
greatly relished by both cattle and horses and has no worse fault
than its slight laxativeness. Yields of 2 to 4 tons per acre of cured
hay are common, and under irrigation they run as high as 8 to 10
tons. Sudan grass can also be cut green and used as a soiling crop
to good advantage. No data on its value for pasture have yet been
secured, but, being an annual, it would have to be resown each
season. ‘The same care should be used in pasturing the second
growth as is customary with the sorghums. In feeding value it is
no doubt practically identical with the sweet sorghums, as the
analyses show it to possess about the same percentages of the different
food principles.

REMARKS.

Sudan grass matures for hay in about the same length of time as
millet and the yields are equal or better, especially where several
cuttings can be secured. The quality of the hay is much superior
to millet hay; therefore it is recommended as a substitute for millet
as a catch crop.

+

UNNI

As a hay crop for the southern Great Plain” 202 766
superior, and it gives promise of being of great value in all Be
of the South except in the humid regions adjacent to the Gulf coast.
Under irrigation three cuttings are obtained and the yields and
quality of the hay are second only to that of alfalfa.

Owing to the high price of seed, seed production has been a source
of great profit. Actual yields of 500 to 2,000 pounds of seed per
acre are reported. As the supply of seed becomes more adequate,
seed production should be limited quite largely to the North, where
the land is free from Johnson grass. Sudan grass crosses quite
readily with the cultivated sorghums, so that in seed production it
is necessary to rogue the fields in order to remove these sorghum
crosses, but when the field is to be used for hay the presence of
crosses is not of any great importance.

WasurneTon, D. C., September 9, 1916.

WASHINGTON : GOVERNMENT PRINTING OFFICH : 1919

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IBRARY OF CONGRESS