FIBERS USED FOR BINDER TWINE. By LYSTER H. DEWEY, Botanist in Charge of Fiher-Plant Investigations, Bureau of Plant Industry, INTRODUCTION. Binder twine is used to tie into bundles nearly 90 million acres of small grain harvested annually in the United States. In addition to the sheaves of wheat, oats, barley, rye, rice, and flax, which are cut by the grain binders, increasing areas of corn are being harvested by corn binders. The quantity of twine required varies widely for light or heavy crops and for different crops, also for different kinds of twine, but as an approximate average it may be estimated at about 2 pounds per acre for small grain and 3 pounds per acre for corn. More than 190 million pounds of binder twine are used annually in the United States. The farmer pays for this more than $15,- 000,000. This twine is used but once and in its use is destroyed. Hay rope may be used over and over again before being worn out, and after that it may be converted into paper stock. But not so with binder twine. No attempt is made to recover it for any purpose, and in one operation it uses up completely more than 90,000 tons of new fiber each year. The demand for binder twine has been a most important factor in the development of hard-fiber production. During the 35 years since self-binders came into general use for harvesting grain in the United States, the production of fiber from the henequén plant in Yucatan has increased more than sevenfold. REQUIREMENTS OF BINDER-TWINE FIBER. A fiber to be used for binder twine must be strong, rather stiff, averaging more than 30 inches long, clean^ and straight, not subject to injury by moisture, mildew, or insects, and it must be compara- tively inexpensive. These requirements are best fulfilled by the hard fibers, abacá (Manila hemp), henequén, sisal, cántala, cabuya, and phormium, and to a less degree by the soft fibers, flax, hemp, and jute. Cotton, which has a wider range of uses than any other textile fiber^ is not suitable for binder twine. All of the hard fibers used in the manufacture of binder twine are imported (See PI. Ill, fig. 1.) The principal kinds of binder twine quoted in the markets are the following: (1) Pure manila (650 feet to the pound), made of a good quality of abacá fiber. 20139**—YBK1911 13 193 194 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. (2) Manila (600 feet to the pound), made of abacá with a mixture of other fibers. (3) Standard manila (550 feet to the pound), made of mixed abacá and henequén fiber. (4) Standard (500 feet to the pound), made of henequén (sisal) colored to resemble abacá. (5) White sisal (500 feet to the pound), made of henequén fiber, sometimes with a mixture of other fibers, but not colored. Abacá, commonly called " Manila hemp," and henequén, known as " sisal " in the trade, are used for binder twine more than all other fibers combined. (PL III, fig. 1.) Other hard fibers used to a lim- ited extent, chiefly for mixing with abacá or henequén, are sisal, phormium, Manila maguey, mescal maguey, cabuya, and mauritius. ABACÁ. The best and highest priced grades of binder twine are made of abacá.^ This fiber is obtained from the leaf stems of the abacá plant {Musa textilis). (PL V, fig. 1.) The abacá plant is nearly related to the banana plant, which it very closely resembles, except that its fruit is not edible. It is native in the warm, rainy districts of the Philippines, where, in many localities, it is still abundant in the wild state. The abacá fiber of commerce is obtained exclusively from plants that are cultivated. Attempts have been made to introduce the cultivation of abacá into southern India, the Andaman .Islands, Borneo, Cuba, and Porto Rico, but owing to unsuitable conditions of soil or climate or to lack of facilities for preparing the fiber, the industry has not become established outside of the Philippines, except in Java. The cultivation of these plants, of which about a dozen horti- cultural varieties are recognized, is confined to limited, warm, moist areas in the Philippines and Java. Abacá requires for successful growth a rich, deep, loamy soil of rather loose texture, moist, yet with good drainage. It must have a rainfall of 60 inches or more, well distributed, so that there may be no severe drought at any season, but the drainage must be such that the water will not remain stag- nant about its roots. Many of the best plantations in the Philippines are on volcanic soils, near the bases of mountains sloping south and east, where there is abundance of rain, good drainage, warm sunshine, and protection from strong winds. Abacá plants produce seeds in black, bananalike fruits, but they are commonly propagated by suckers which spring up from the roots. 1 The name abacá is preferred to Manila hemp because neither the plant nor the fiber bears any relation to true hemp. FIBEES USED FOR BINDER TWINE. 195 These are set out in rows about 8 feet apart each way, and the soil around each plant is kept free from weeds by hand cultivation with the bolo or hoe. On some of the well-managed plantations better results are obtained by thorough, clean cultivation with cultivating tools drawn by mules. The plants attain a height of 15 to 20 feet. The first stalks are cut about 18 months after setting out the suckers. The leaves are trimmed off, leaving the trunk 8 to 12 feet long and 5 to 8 inches in diameter, composed of the leaf stems over- lapping in concentric layers, extending nearly from base to summit. The trunk is separated into these component leaf stems 6 to 10 feet long, 5 to 8 inches wide, and about three-eighths of an inch thick. The leaf stems in turn are split into strips 1 to 2 inches wide and the spongy inner portion is scraped away, as the good fiber is only in the thin outer layer of each successive sheathing stem. The thin, flat ribbons, or "tuxies," thus prepared are drawn by hand under a blunt knife pressed by a spring against a wooden block. This process scrapes away the pulp, leaving clean white abacá fiber. The fiber is dried in the sun and after sorting is ready to be baled for market. Twelve different grades of abacá are quoted on the market, the differences resulting chiefly from greater or less care in cleaning and preparing the fiber. These grades range in price from about 5 cents per pound for the lowest to about 10 cents for the highest. Most of the "pure manila" binder twine is made of the "midway," or medium, grade, ranging between the grades known as " fair current " and " good current." HENEQUÉN. The largest quantity of binder twine is made of fiber obtained from the leaves of the henequén plant (Agave fourcroydes). (PI. IV, fig. 1.) This fiber is commonly known in the trade as " sisal," because it was formerly shipped from the port of Sisal in Yucatan, but it is different from the fiber of the true sisal plant. Henequén is native in southeastern Mexico, and it is cultivated in Yucatan and Cam- peche and to a limited extent in the States of Chiapas, Sinaloa, and Tamaulipas, Mexico, and also in Cuba. It is rarely seen outside of these regions. It requires a hot, dry climate and well-drained lime- stone soil. In Yucatan, where it thrives best, the lowest recorded temperature is 48° F., and the annual rainfall is about 30 inches. The atmosphere is very dry, except when it is actually raining, and the porous limestone soil affords excellent drainage. This soil also permits free access of air to the roots, which is necessary for the best development of henequén. Henequén plants produce seeds and bulbils, similar to top onions, but they are propagated chiefly by suckers which grow from the root- 196 YEARBOOK OF THE DEPAETMBNT OF AGRICULTURE. stocks. The suckers are set out in rows about 9 feet apart and about 6 feet apart in the row. The vegetation between the plants is kept down usually by cutting with machetes. Better results are obtained by clean cultivation where the land is not too stony. The first crop of leaves is cut 4 to 7 years after planting, usually the sixth or seventh year in Yucatan, and after that annual or semi- annual crops are cut for 10 to 20 years. Only the two outer or lower rows of leaves are cut at each harvest, leaving the others to develop. The spines on the point and margins are trimmed off and the leaves are tied in bundles of 50 each and taken to the cleaning machines. Nearly all of the henequén fiber of commerce is cleaned by machinery within 48 hours after the leaves are cut. Most of the machines work on the same general principle. The leaves, fed side- wise in a continuous row at the rate of 3,000 to 30,000 an hour, are grasped near the center and carried forward past a rapidly revolving wheel with scrapers which beat and scrape away the pulp from one end of the leaf. The grasping device is then shifted to the cleaned fiber, and the leaf is carried on past another wheel which scrapes away the pulp from the other end of the leaf. (PI. V, fig. 2.) The fiber, cleaned in this manner in about six seconds, is dried in the sun and is then ready to be baled for market.