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varies in weight from 300 to 400 pounds, averaging about 340 pounds. The brush is sorted at any convenient stage of the process. The most crooked brush can best be discarded in the field, while final sorting may be made just before baling. The production of broom corn is best engaged in by those who make it a specialty after having studied the business carefully in all its details.
iv. USE AND PRODUCTION. 559. Use.—As a food for horses, cattle and swine, sorghum seed is not considered the equivalent of maize. It is less palatable and cannot successfully enter so exclusively or so continuously into their diet. On account of their more highly carbonaceous character large quantities of leguminous foods should be fed. The seeds are somewhat astringent, especially in the red Kafir variety, and when fed in large quantities cause constipation. As a food for poultry it is highly prized. As a food for calves raised on skim milk it is highly commended both because of its high proportion of carbonaceous material and because of its tendency to overcome scouring. After a number of feeding trials, the Kansas Station concludes that the best way to feed the grain to fattening hogs is to place it unground into the feeding troughs and to pour over it sufficient water so that a small quantity will be left after the hogs have finished eating the grain. The purpose of the water is to lay the dust which, when the grain is fed dry, causes the hogs to cough severely. For cattle and horses the grain is usually ground, but whether grinding is best has not been experimentally determined. Large quantities of sorghum are raised for the fodder, handled after the manner of maize fodder, or sown thicker and cut less mature as hay. It is also used for soiling, for which it is highly prized, for silage and for pasture. While large quantities of the nonsaccharine sorghum are used for this purpose, sweet sorghum is recommended as preferable. In the Southern States, where sorghum is sown as a hay crop, sometimes two and even three crops are harvested in one season; the plant, when cut
1 Kan. Bul. 33, p. 40
immature, possessing the ability to throw up new culms. Sweet sorghum is also used for the production of syrup, and formerly for the production of sugar, for which it is well adapted. The production of sugar from sugar cane and from sugar beets being more economical, the production of sugar from sorghum has been practically abandoned.
The seed of both Kafir corn and broom corn has been used to a limited extent in the production of flour. Although bread of an inferior quality may be made from it, it is chiefly used for the production of griddlecakes.
560. Danger from Use.—Many cases have been reported of animals dying suddenly from eating second growth or frosted sorghum. This was formerly believed to be due to bloating, and deaths may perhaps occur from this cause; but it has been pretty well demonstrated that deaths occur from violent poison which is found in sorghum of stunted growth. This poison is now believed to be due to prussic acid. Investigations of the Nebraska Station show that the prussic acid is not present as such but that it is liberated as a glucoside by an enzyme in the plant. It appears that this glucoside is always present in the plant, but the plant is harmless except under conditions which favor the action of the enzyme. The conditions which favor action of the enzyme are not fully understood; but it is believed that dry, clear weather, by arresting the normal development of the plant, is the chief cause of the formation of abnormal quantities of poison.
561. SORGHUM SUGAR.—During the past twenty-five years the production of sugar from sorghum has been thoroughly studied, and several plants have been established in different States for its manufacture. While a considerable quantity of good sugar has been produced, most of the factories have been unsuccessful financially. Some of the difficulties have been:
1. A rather small yield of cane. The yield of cane has varied under normal conditions from about five to ten tons of clean cane per acre.
2. A low average percentage of sugar in the cane. The percentage of sugar is much more variable than in sugar cane or beets. The other solids are higher,
1 Neb. Bul. 77.
thus making the percentage of available sugar still less. The total per cent of sugar in the juice of sorghum manufactured commercially has probably been con. siderably under ten per cent.
3. The rapid deterioration of the sugar in the sorghum from unknown causes, usually considered climatic, or from improper handling. Sugar cane may lie some weeks before it is used; beets may be stored for months; sorghum must be used at once.
4. Imperfect methods of extracting the juice. 5. Improper treatment of the extracted juice.
All these difficulties must be overcome before the manufacture of sorghum sugar can be a success. In the nature of the case the first three items are the most serious.
Manifestly, continued experiment may find some localities especially adapted to the production of high yield. The Delaware Station reports yields of cane varying from ten to twenty-five tons per acre, with available sugar varying from 2,700 to 6,600 pounds per acre, thus comparing favorably with the production of sugar from sugar cane or sugar beets. This result has been brought about partly by local adaptation, partly by cultural methods and partly by selecting during ten years seed from sorghum of high quality. Beginning with an amber cane in 1889 containing eleven per cent of sugar with a purity of sixty-five per cent, canes were produced in 1898 with more than twenty-one per cent of sugar having more than eighty-three per cent purity.
Some improvements in the removal of the leaves and heads from the canes and in the extraction of the juice have been effected, in the opinion of the Delaware Station. It is also proposed that the difficulty due to the perishable nature of the sorghum may be overcome by several small plants for cleaning the cane and extracting and concentrating the juice, with a central factory for the extraction of the sugar.
“ To summarize, use seed from cane testing as high as possible in sugar, from 15-18 per cent, with juice purities in excess of 80 degrees. Select land which will produce fifty bushels or more of corn after repeated manuring with crimson clover, which crop may have been pastured down or plowed under, or cured as hay. Fertilize with muriate of potash broadcast at rate of 160 lbs. per acre. To this add 150 lbs. of nitrate of soda, provided some crop other than crimson clover has immediately preceded sorghum. Seed during the last fortnight in May, in rows 36 inches apart. Let each row consist of two lines of plants 4 inches apart, and in these lines let the plants stand at regular intervals of 6 inches. To each plant would then be given 108 square inches of soil surface. Cultivate as if for Indian corn. Prepare to begin milling during the last fortnight in September, provide cane for sixty days' work, to close November 15th. Such a field so planted and tilled should yield raw sugar in excess of 5,000 lbs. per acre." ]
562. SORGHUM SIRUP.-Sweet sorghum is mainly grown for the production of sirup, although its production for this purpose has declined. Sorghum juice has a larger proportion of solids not sugar than maple juice or sugar cane juice and when
1 Del. Bul. 51 (1901), p. II.
these impurities are not removed they impart to the sirup an undesirable taste. As ordinarily manufactured, therefore, sorghum sirup is not as highly prized as maple or cane sirup, although good sirup can be made from sorghum by properly clarifying the juice. The process of manufacture is extremely simple or complex, depending upon the amount to be handled and the extent of the clarification. As rapidly as the canes are cut, which is when the seeds are in the dough stage, the heads and leaves are removed and the canes crushed between rollers to extract the juice. În the more simple processes the clarification is accomplished by skimming and decanting the liquid after allowing the sediment to settle.
These processes are assisted by neutralizing the natural acids present with lime, by boiling to coagulate organic substances, and by adding clay to weigh down the suspended materials. After clarification the liquid is condensed until it weighs about eleven and one-half pounds per gallon. On account of the rather large proportion of uncrystallizable sugar, there is comparatively little danger of granu. lation with sorghum sirup or "molasses.” With a properly adjusted mill, the cane will yield sixty per cent of its weight of juice and yield as a maximum about twenty gallons of sirup per ton of clean cane.
563. Sorghum Crop of the World. The seed of sorghum, under the name of millet or durra, enters into the dietary of a large proportion of the people of Africa and the drier and warmer portions of Asia. There are no statistics concerning its production. While it is not so palatable, it is not improbable that it is quite as important as is rice. The use of sorghum for sugar has been largely confined to America. It is somewhat but not extensively raised in Europe for fodder. Broom corn is raised both in Italy and France as well as in the United States.
564. Sorghum Crop of the United States.—Something less than 200,000 acres of sorghum seed were reported by the census of 1900 under the name of Kafir corn, almost all of which was raised in Kansas, Oklahoma, Texas and California. Much larger quantities, however, are raised for forage. The production of sorghum for forage is not listed separate from maize by the census, but of three millions so listed, more than half is grown in Kansas, Oklahoma and Texas, and one-third by Kansas, where both the sweet and nonsaccharine varieties are known to be extensively raised. In 1899 sweet sorghum was raised for sirup upon 447,000 farms, each farm raising on an average less than an acre. The principal acreage is in the Southern States. None of the North Atlantic or Western States produces any considerable quantity. Kansas and Missouri are the principal producers among the North Central States. The yield per acre of cane was 6.5 tons and of sirup fifty-eight gallons. The total acreage of Kafir varieties in Kansas in 1899 was reported at 619,000 acres, of which 155,000 acres were raised for seed.
565. Yield per Acre.—As a grain crop, sorghum is more productive than maize in the semiarid districts. The Kansas Station reports an average yield for eleven years ending 1899 of forty-six bushels per acre of Kafir corn and thirty-five bushels per acre of maize. Their highest yield in any one year was Kafir corn ninety-eight bushels and maize seventy-eight bushels. In the semiarid districts west of the Kansas Station it is believed that the relative difference in yield is still greater. The average yield of broom corn in 1889 was 509 pounds of brush per acre, averaging four cents per pound, which has been the average price of broom corn brush in Illinois for the twenty-five years ending 1901. One-third of a ton of standard brush or one-fifth of a ton of dwarf brush per acre is considered a satisfactory crop.
566. History.-Sorghum is probably indigenous to tropical Africa, whence it was introduced into Egypt in prehistoric times and from there into India and finally into China. Sweet sorghum was introduced into the United States in 1845 and widely disseminated through the influence of Orange Judd. The Kafir varieties now generally grown for seed were introduced about 1885 by the United States Department of Agriculture. Their cultivation has been rapidly extended in the regions to which they are especially adapted. Broom corn has been cultivated in this country for more than 100 years. Brewer believes the use of sorghum for the production of broom origi.
i Origin of Cultivated Plants, p. 382.