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Cereals have been throughout history and are unquestionably the most important sources of plant food for humans and livestock All of the original ancestors of cereals have been lost over the millennia that they have been cultivated. The development of all the major cereals occurred long before recorded history for all the oldest civilizations were already familiar with several kinds of barley, wheat and other grains. Also the actual origin of these cereals had been so long forgotten that they were given supernatural powers and played a part in the religious ceremonies of the various nations of antiquity (Hill 1952).
In ancient Rome they held festivals at seeding time and harvest in honor of the goddess of Ceres, whom they worshipped as the giver of grain. They brought offerings of wheat and barley to these festivals, the “cerealia munera” or gifts of Ceres, from which the name “cereals” was derived. In ancient Greece similar religious ceremonies were observed. In America the natives of Mexico worshipped an agricultural deity to whom they brought the first fruits of their harvest.
All cereals are members of the grass family, Gramineae, and are similar in possessing the characteristic fruit of that family, the karyopsis. In this fruit the wall of the seed is fused with the ripening ovary wall to form the husk. The term “grain” is given either to this type of fruit or to the plant that produces it. There are six true cereals in the world today, which are Wheat, Rye, Rice, Oats and maize. Of these wheat, maize and rice are the most important, and each has played roles in the development of civilizations. The millets, sorghums and even buckwheat are often referred to as cereals, but they belong to a different classification.
There are many reasons why cereals are such important crops. One of more of these grasses is available in each of the different world climates. The northern regions have barley and rye, the temperate regions wheat and the tropics and warmer temperate areas rice and maize. Cereals also have a wide range of soil and moisture requirements. They can be cultivated with a small amount of effort and give a high yield. The grains are relatively easy to handle and store because of their low water content, and they are very high in food value. Cereals contain a higher percentage of carbohydrates than any other food plants as well as a considerable amount of protein and some fats. There are even vitamins present. In modern times the quest for greater yields has sometimes sacrificed flavor, and low yielding varieties that may possess characteristics of quality are gradually being ignored or even lost. This is especially noticeable in the cold cereal industry that produces an array of products few of which match up in flavor or texture to those of the earlier 20th Century. Some high latitude areas of South America have managed to continue production of superior cold cereal products for local consumption.
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This is the most widely grown cereal of temperate regions. Its native home is not definitely known because it is so ancient. There are some indications that highlands in Syria and Palestine might be the place of origin, but the Central Asian plateau and the Tigris and Euphrates valleys might be included. Of course Vavilov considered wheat to have had multiple origins, the soft wheats originating in the mountains of Afghanistan and the southwestern Himalayas, while the durum or hard wheats may be from Abyssinia, Algeria and Greece and the einkorn variety from Asia Minor. Archeological evidence indicates that wheat had already been cultivated by earlier than 4,000 B.C. Wheat was at the core of Babylonian civilization and it was cultivated by all the other Old World nations of antiquity. Aristotle, Pliny and Theophrastus all mentioned numerous varieties of wheat. In China it was grown by 2,700 B.C. and was used by the lake Dwellers of Switzerland and Hungary, civilizations that go back to the Stone Age. Wheat was first introduced into America at Mexico in 1529. Wheat was sowed in New England in 1602 and it reached Virginia by 1611, California by 1769 and Minnesota by 1845 (Hill 1952).
Wheat is an annual grass in the genus Triticum that comprises a large number of wild as well as cultivated species. The wild species are often weeds. Cultivated wheat, Triticum aesticum, reaches a height of 2-4 ft. The flower is a terminal spike or head consisting of 15-20 spikelets that are borne on a zigzag axis. Individual spikelets are sessile and solitary, consisting of 1-5 flowers each. The mature grain consists of the embryo (6 %), a starchy endosperm (82-86 %), the nitrogenous aleurone layer (3-4 %), and the husk or bran (8-9 %). The husk is made up of the remains of the nucellus, the integuments of the seed coat and the ovary walls or pericarp.
Innumerable species and varieties of wheat have arisen over its long period of cultivation. This was the result of intentional or unintentional selection on the part of humans of forms that had some particularly desirable qualities. Eight principal kinds of wheat were were differentiated as species by Hackel: einkorn, Polish wheat, emmer, spelt common wheat club wheat durum wheat and poulard wheat (Hill 1952). Modern classification has been on the basis of chromosome number with the most important species falling into three groups: Diploid (7 pairs) = Triticum monococcum; Tetraploid (14 pairs) = T. dicoccum, T. durum, T. polonicum, T. timopheevi and T. turgidum; Hexaploid (21 pairs) = T. compactum, T. aesticum and T. spelta. Various varieties of these species have been produced at different times.
Einkorn, emmer and spelt are the most primitive. They resemble the wild species of Triticum with fragile jointed heads that break during threshing and the grain does not separate easily from its enclosing envelopes.
Triticum monococcum has been called “One-grained Wheat” because it has only one fruit in each spikelet. It is one of the oldest species, dating back to the Stone Age. It is a plant that can be grown in very poor soil and will therefore is useful in regions where other types cannot survive. Einkorn is a small plant, rarely 2 ft. in height with a very low yield. It is still cultivated to some extent in mountainous regions of Southern Europe, especially in Spain. It is not used much for baking but primarily for animal feed. In other places it continues to be grown for experimental purposes.
Emmer, Triticum dicoccum, is also known as “Starch Wheat,” “Rice Wheat,” or “Two-grained Spelt.” It has a flattened head with bristles or awns. It is another very old type that was grown in Babylonia and by all the early Mediterranean civilizations and the lake Dwellers of Europe. It is still cultivated in the mountainous areas of Italy, Spain, Germany, Switzerland and Russia. It thrives in dry soil. After being introduced into the United States from Russia it was used for livestock and breakfast foods and in experimental breeding efforts.
Triticum spelta is another primitive wheat of antiquity, spelt is hardy and can be grown in the poorest soils. It has been cultivated in the Mediterranean region for centuries and is still grown in Spain. In North America is has been used as livestock feed.
Polish wheat, Triticum polonicum, or “Giant Rye” has a very characteristic appearance due to the long papery bracts surrounding each spikelet. The stems are solid and the bluish-green ears are flattened. The species is of comparatively recent origin. Despite its name it did not originate in Poland. It has been grown chiefly in Spain and Italy, Turkestan and Abyssinia. The plants are large, but have a small yield of little value. Polish wheat has not proven to be well adapted to North American growing conditions because it gives a low yield.
Also known as “English Wheat” or “River Wheat”, Poulard Wheat, Triticum turgidum, is an old species that probably originated in dry portions of the southern Mediterranean region. The heads are large but the yield is small and the plant is only of importance in England. Elsewhere it is grown only in small quantity.
Triticum compactum (tenax), also called “Dwarf Wheat” or “Hedgehog Wheat” is different from all other species in having short compact heads and small kernels. The plants are small and have a very stiff and strong straw. Club Wheat is well adapted to poor soil and is grown chiefly in the mountainous areas of Central Europe, Abyssinia and Turkestan. It has been grown in Chile and in the Western United States. The grains are soft and have low protein content, so the flour is not used for bread but rather for pastry flour.
Triticum durum has a thick head with long stiff beards and large, hard, amber or red grains that are rich in gluten. This species has been cultivated for a long time in the arid regions of the Old World. It is the main wheat in Spain and is also grown in Algeria, India and Russia. Durum wheats were introduced into North America from Russia and have been extremely valuable. The low rainfall and high temperatures typical of the Great Plains renders the region unsuitable for most other crops without irrigation. These wheats are very hardy and drought tolerant. Their high gluten content makes them especially suitable for macaroni, semolina and other types of pastas. They are mixed with other flour in bread baking. Red durum wheats are used for livestock.
Triticum vulgare is the principal source of bread flour. These wheats occur in innumerable varieties differing in both external morphological and physiological characteristics. There are bearded and beardless varieties, red and white varieties and hard and soft varieties. The hard wheats are richer in proteins and usually have small grains; the soft wheats produce large grains that are richer in starch. The physiological characteristics include such things as yield per acre, late or early maturing, resistance to drought, cold or disease; behavior in milling and baking, and the season that they are sown (spring or winter). Spring wheat is sown in the spring and harvested in late summer. Winter wheat is planted in the autumn and develops a partial root system before the onset of cold weather. In the spring it has a vigorous early growth and can be harvested in early summer. Winter wheat has a higher yield, is more resistant to disease and matures earlier.
Triticum timopheevi from Russia is especially resistant to disease and thus has been used in breeding programs with standard varieties.
Seven grades or classes of wheat are recognized by the United States Department of Agriculture. The five most important are Hard Red Spring Wheat, Durum Wheat, Hard Red Winter Wheat, Soft Red Winter Wheat and White Wheat.
About 20 percent of the wheat grown in the United States has been Hard Red Spring Wheat. They are grown primarily in Minnesota, North & South Dakota and Canada where the winters are too severe for winter wheat. They are used for bread flour. Marquis Wheat has been one of the chief varieties.
Amber durum wheats are all spring wheats and include at least 10 varieties. Kubanka is a well-known variety. They make up about 6 percent of the wheat crop and are grown mainly in North & South Dakota and Minnesota. Their use is almost entirely for macaroni and other pastas.
This grade of wheat is grown primarily in the central and southern Great Plains where hot summers and severe dry winters are common. Kansas, Nebraska, Texas and Oklahoma lead the production, and this wheat makes up about 47 percent of the total crop. Turkey is a common variety. The flour is of high bread making quality.
This group constitutes about 30 percent of the United States wheat crop. It is the principal wheat grown east of the Mississippi River and is centered in Ohio, Indiana and Illinois. It is also cultivated inn the Pacific Northwest. It is adapted to a more humid climate than the other wheats. The grains are starchier and the flour is used for pastry, cake, breakfast foods and home baking. This group also includes the red club wheats.
This group makes up about 5 percent of the United States wheat crop and it comprises all of the white-grained forms, whether common wheat or club wheat, and includes both hard and soft and spring and winter wheats. They are grown in the Pacific Northwest and in the northeastern United States. The flour is used for pastry and breakfast foods and is blended with hard-wheat flour for bread making.
Wheat is best adapted to moderately dry temperate climates, and is not grown in warm humid regions. Climates with a growing season of at least 90 days and an annual rainfall of not less than 9 inches are essential. Over 30 in. of rain is detrimental. Generally regions with a cool moist spring merging into warm, bright, dry harvest periods are the best, but the various kinds of wheat differ in their requirements. Good climatic conditions for wheat are found in nine different areas in the world and these are the principal wheat-producing regions. They include the plains of southern Russia and the Danube, the Mediterranean countries, Northwestern Europe, the central plains of the United States and Canada, the Columbia River basin in the Pacific Northwest, Norwest India, north central China, Argentina and Southeast Australia.
Clays and loams are the best soils for wheat although a light sandy soil may be used. If the ground is too wet the plants lack vigor and produce a small yield. But a porous soil does not hold sufficient moisture. Lime is an essential element and must be added if the calcium content of the soil is low. Nitrogen, Phosphorous and potassium are also required. The best fertilizer is barnyard manure.
The land must be thoroughly cleared for wheat is easily choked out by weeds. Crop rotation is generally practiced and wheat is planted after a crop of beets, turnips or tobacco that kill out weeds. The methods of cultivation naturally vary depending on the kind of wheat and the character of the soil and climate. The time of sowing depends on whether the plant is a winter or summer crop. For a good harvest the seed must be heavy, well developed and fully ripe. Only the finest ears are used for seed. The grains are winnowed to remove dust and light grains. They are then sifted and bolted and are treated with chemicals to kill any fungus spores. Wheat may be sown broadcast, either by hand or by machine, the former method being confined to small farms. Two kinds of machines are used on large farms. One sows the wheat broadcast and the other drills furrows and buries the seed all in one operation. Germination begins immediately and the first leaves appear within two weeks. Inn the case of spring wheat growth continues unchecked until maturity, but in winter wheat it is halted with the advent of frost. If the cold is too severe or if the roots are exposed, winter wheat may die. Weeding is constantly required. On the largest farms machines are used which plow 24 furrows at one time. The various stages of the ripening grain are known as milk-ripe, yellow-ripe or dough, full ripe, and dead ripe. Wheat is not always allowed to mature fully for it is then more valuable for livestock feed. Several insect and fungus pests attack wheat. The latter include bunt, smut and rust. Wheat rust causes colossal losses, often wiping out a whole crop. Many attempts have been made to import rust-resistant varieties, as well as drought-resistant varieties, and continuing efforts are made to produce them experimentally.
Methods of harvest vary with the size of the farm. Various kinds of simple reaping scythes, reaping hooks or machines continue to be used in underdeveloped areas to cut the culms and binding machines bind them into sheaves. The wheat is then stored and must be kept dry. Threshing is the next process. This involves the separation of the grain from the spike. This has long been done by hand, using a flail. It is a long and tiresome process, but is less damaging to the grain than a threshing machine. The wheat is laid in rows all pointing in the same way to a depth of 1 in. These rows are then struck at regular intervals with the flail, and then the wheat is turned and the process repeated. A cart that traces a spiral course over the stalks has been widely used in Europe. After threshing the wheat is winnowed and sifted. Threshing machines are frequently used. These are either horizontal or vertical and consist of rapidly revolving drums of hard wood, provided with barbed beaters that struck the ears with a substantial force and with a frequency up to 800 r.p.m. The most complicated harvesting machines, the combines, are used for large acreages. They reap, clean, thresh, winnow and sift the grains, separate the wheat from the chaff, eliminate foreign seeds, sort into grades and bag the grain, leaving the bags behind and finally binding the straw. These huge portable factories are more and more mechanized, but used to be drawn by horses. They can cut a swath over 40 ft. wide. It is possible with the aid of less than eight people to harvest 120 acres each day.
Storage must be in firmly built, well-ventilated structures to keep out grubs and small pests. Buildings with a concrete wall and floor are best suited for storage. Subterranean silos are constructed in tropical areas. The great grain elevators at world ports are often startling sights.
The grains were “brayed” between two stones in ancient times. Then a mortar and pestle was used, and later millstones operated by wind or waterpower. Most of the old mills had a fixed lower stone upon which a movable upper stone revolved. The grains were dropped into openings in the upper stone and gradually worked out between the stones that had grinding surfaces cut in radiating lines. The whole grain was milled.
The roller process of milling was then perfected. The first step in this process involves cleaning and scouring. This consists of screening, to remove all foreign seeds, dust, sticks, straw and pieces of bran. The grains are then thoroughly washed and scoured. The next step is tempering. This prepares the grain for the best condition for milling. A little water is added that toughens the bran and prevents it from breaking up so that it will flake out all in one piece. Finally the conditioned and tempered wheat is submitted to breaking, grinding and rolling. The grains are first ground between corrugated iron rollers, the so-called “first break.” This cracks the grain and almost flattens it. A small quantity of flour, the “break flour” is separated out by sieves while the main portion goes to the “second break” for more complete flattening and the partial separation of the bran and embryo. This process is repeated until five sets of rollers, each moving at a different speed, have been used. In each case bolting separates the ground material from the coarse bran. After a while all the bran is removed and the purified material is passed to smooth rollers for final granulation. Finally it is bolted with a cloth (originally silk) containing 12,000 meshes per square inch and is then ready for packing. The final product is the best grade of flour or the “First Patent. Material that has been separated out is known as middlings and may be processed and made into inferior grades of flour, or used for other purposes. Granular particles midway in size between the grain and flour, are known as semolinas. Durum wheat semolina is used for macaroni and ordinary wheat semolina for farinas.
The above-described process produces white flour. In the milling of graham flour the entire grain is used while in whole-wheat flour only a part of the bran is removed.
The world production of wheat increases steadily with the United States producing over one-quarter the amount. Kansas and North Dakota are the leading states. Other large wheat-producing countries are Russia, China, Canada, India, France, Italy, Germany, Argentina, Turkey and Australia.
France has led in the per capita consumption of wheat, followed by New Zealand, Australia, the United States, Great Britain, Germany and Canada. The United States per capita consumption of wheat was once estimated at 4.5 bushels.
Wheat products are almost certainly the most widely used articles of the human diet. In the United States they furnish about one-fifth of the total food materials of an average family. The flour is used mainly for making wheat bread. Where other cereals are used the produce is called corn bread or rye bread, etc. The hard wheats provide bread flour while the flour from soft wheats is used for cakes, biscuits, pastry, crackers, etc. Other edible by-products are breakfast foods and the various farinas; and the pastas such as macaroni, spaghetti and noodles. Semolinas are used for macaroni. These are separated from the flour and bran and mixed with 30 percent water. The resulting dough is kneaded and put in a hydraulic press. The dough is squeezed out through holes in the bottom. Each hole has a little pin in the center with the result that a hollow tube of dough is formed. Strings of dough are cut into 3-ft. lengths and are dried and cured at a temperature of 70 deg. Fahrenheit. Spaghetti and vermicelli are merely small types of macaroni. Rolling out the dough into thin strips makes noodles. Durum wheat is used for macaroni.
Wheat is also used in the manufacture of beer and other alcoholic beverages and industrial alcohol. It is an excellent livestock feed. A special kind is grown for the preparation of starch for use in the sizing of textile fibers. Wheat straw excels all other kinds because of its very great strength. It has been used for seats of chairs, mattress stuffing and the manufacture of such diverse articles as straw carpets, string, baskets, beehives and wickerwork. Leghorn hats are straw hats made from the bearded wheat of Tuscany. Wheat straw is also used for packing and thatching and as a fodder and manure. The entire wheat plant is also a valuable source of fodder.
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Indian corn or maize, Zea mays, is America’s main contribution to the important group of cereals. Maize had been thought to have originated in a wild state in the lowlands of southern Mexico and Central America from which it spread to the Andes where its cultivation goes back to prehistoric time. The ancestor was probably teosinte a primitive ancestor that bore a single row of kernels in a husk. Selection in southern Mexico resulted in a cob with several rows of kernels. Later development produced the longer cob or ear familiar as the commercial maize of modern times. Grains of this later variety maize found in the tombs of the Incas in Peru represent several different varieties, so that the plant must have been grown for many centuries prior even to the period of the Inca civilization. From Peru is has been thought to have moved northward again and played a prominent role in the civilization of the Mayas and Aztecs. The Amerindians in New Mexico grew it as early as 2,000 B.C. By the time of Columbus maize was growing all the way from the Great lakes and the lower St. Lawrence valley to Chile and Argentina.
Maize was introduced into Europe by Columbus, or possibly earlier, and into Asia by the earlier Portuguese explorers. It is now grown worldwide. Large yields are possible from maize even under primitive conditions of agriculture.
The largest of all cereals, maize is a tall annual grass that can attain a height of 3-15 ft. The jointed stem is solid and contains a considerable of sugar when not mature. The leaves are large and narrow with wavy margins. There is an extensive fibrous root system with aerial prop roots at the base of the stem. Two kinds of flowers are the tassel, at the top of the stem, which bears the staminate flowers and the cob or ear with pistillate flowers. The ear is produced lower down on the stalk and thus is protected by the leaves. Each ovary has a long silky style, the corn silk. The ovaries, that become the mature grains, are produced in rows on the cob. A husk composed of leafy bracts surrounds the cob. The grains have a hull (6 %), protein or aleurone layer (8-14 %), endosperm (70 %) and embryo (11 %). Two kinds of endosperm are usually present: a hard, yellow endosperm and a soft white starchy endosperm.
There are no known wild species of the genus Zea, but The original ancestor was most likely a pod corn that gave rise to maize through hybridization between some species of Tripsacum and Teosinte, Euchlaena mexicana, a wild relative in Mexico. It is comparatively easy to perform breeding trials with maize; even the Amerindians had learned how to select, produce and preserve the best varieties that gave rise to easily cultivated and rapidly maturing varieties.
No other cereal has so many different varieties that fall into seven quite distinct classes all of which breed true to type. These are pod, pop, flint, dent, soft, sweet and waxy. Although they readily hybridize there are very little intermediate types produced. The classes differ mainly in the nature of the endosperm and the shape of the grain and have been considered by some authorities to be species and others to be varieties. Hill (1952) believed that they should be considered as agronomic groups.
Each grain is covered with a husk in Pod Maize. The plant is very leafy and the tassels heavy. The grains may resemble those of any of the succeeding types, which suggests that pod maize might be very close to the primitive form from which the others had been derived. Pod maize has little if any commercial value.
The grains are usually elongated and oval. Although small in size they are exceptionally hard and flinty with a tough hull. The endosperm is mostly of the hard glossy variety. On exposure to high temperatures, the grains explode forming a snow-white fluffy, palatable mass or Popcorn. It results as a sudden expansion of the soft endosperm that turns the grain inside out. It is probably due to the expansion of the moisture content of each individual starch grain after partial hydrolysis during the heating phase. For a time the flinty protein layer confines the swelling endosperm, but eventually this breaks and the sudden release of pressure causes the endosperm to become everted about the embryo and hull. The presence of too much white endosperm prevents popping. There are two kinds of popcorn: rice popcorn, in which the grains are pointed and tend to be imbricated, and pearl popcorn, in which the grains are rounded and very compact. The plants produce a large number of small ears. This type of maize was undoubtedly grown in prehistoric time. There are over 25 different varieties grown for human consumption.
The embryo and white endosperm are entirely surrounded by the hard endosperm in Flint Maize leaving an undented grain. Plants attain a height of 5-9 ft, and tend to have two ears. The ears are long and cylindrical with hard smooth grains in 8-16 rows that tend toward different colors. Flint maize matures early and so is grown in New England and other colder areas of North America.
The endosperm extends to the top of the grain in Dent Maize, with the hard endosperm being present only on the sided. This causes an indentation of the mature grain at the top due to the shrinking of the softer material. This is the largest maize, stems sometimes attaining a height of 15 ft. A single ear is produced. They are very large, up to 10 in. long, weighing three-quarter pounds and sometimes having as many as 48 rows. The deep wedge-shaped grains are generally yellow or white. Dent maize is the main type grown in the Corn Belt of the United States as it gives an enormous yield. It is the source of most of the commercial grain and also of livestock fodder and ensilage. Over 330 varieties have been developed.
The endosperm is entirely lacking in Soft Maize. This is a very old type that was extensively cultivated by the Amerindians because of the ease with which it could be crushed. The grains resemble flint maize in shape and appearance, but the size varies from small forms to the large Cuzco variety of Peru that are 3/4 in. or more in diameter. Over 30 different varieties are known. Maturity is very late in the season and it is not grown in any quantity in North America.
In Sweet Maize the entire endosperm is translucent, and the starch has been partially changed to sugar. The grains are broad and wedge-shaped with a typical wrinkled surface. The plant is adapted to the cooler areas and is the main type grown in northern areas of North America for canning purposes. The grain is used in the unripe state. Over 65 varieties have been developed.
The endosperm is waxy in Waxy Maize and the carbohydrate material occurs in a different form from that in other varieties. It is used as a substitute for tapioca. The starch is entirely amylopectin, whereas ordinary cornstarch is a mixture of amylopectin and amylose.
Being summer annual maize requires very definite environmental conditions for proper development. The plant does best in a fertile, friable, well-drained alluvium, such as the deep, warm, black loams along river bottoms and in drained swamps. These soils must have a high organic and nitrogen content and must not bake out. Additionally, temperature, sunlight and moisture are limiting factors. The temperature of both the air and soil is important, especially during the growing season from May to September in the Northern Hemisphere (November to March in the Southern Hemisphere). A mean average summer temperature of 75 deg. Fahrenheit is optimum, but temperatures below 66 deg. Fahrenheit are detrimental. Cloudy days hinder development. Adequate moisture is essential, with the optimum being a 20-inch annual rainfall occurring mostly in summer. There is a great difference in growth habit under different climatic conditions and there are varieties adapted to each type. A continental climate is most favorable. The growing season varies from 90-160 days, depending on the locality. Maize does mature adequately north of 50 deg. of latitude although it can be grown there as livestock fodder.
There are relatively few regions that have the right combination of the necessary environmental conditions and where maize can be raised as a commercial crop on a large scale. The principal maize growing regions of the world include the east, central and middle western United States; the Mexican plateau; the Argentine pampas; the highlands of Brazil; the basins of the Danube, Dnieper and Po river in Europe; northern India; China and Manchuria; Vietnam; java; the Nile valley; and South Africa. The most prolific area for maize is the great Corn Belt of the United States, located in the Mississippi valley in the states of Illinois, Indiana, Missouri, Iowa, Kansas and Nebraska.
To grow maize on a commercial scale the fields must be well plowed and harrowed. The seed is planted to a depth of 1-3 in. in regularly spaced rows. Constant weeding and hoeing are necessary with care necessary not to injure the roots. The use of fertilizers and crop rotation are advisable. Maize has comparatively few natural enemies, the corn borer being the worst insect and corn smut the most serious of the fungus pests. Drought may cause very serious damage.
There have been very few changes in harvesting procedures over the millennia. On small farms the ears are still husked by hand directly in the field, and cattle are allowed to graze on the stalks. On larger farms the maize is cut with a corn knife or a machine. The stalks are stacked to permit additional ripening of the grain. After a month of this curing process the ears are husked by machine. Maize must be stored in well-ventilated bins to allow excess moisture to evaporate and to properly protect against rodents and small pests.
No cereal is used in so many ways as Maize. About one-half the crop is used as a food for livestock. The grain is very nutritious with a high percentage of easily digested carbohydrates, fats and proteins and very few deleterious substances. The pork industry is dependent almost entirely maize in the United States and has used about 40 percent of the total amount raised. Cattle, horses and other domestic animals are also fed maize. It has been estimated that 10-12 lbs. of maize is converted into 1-lb of beef, while 5-6 lbs. yields 1-lb. of pork. Not only is the grain valuable as a livestock feed but the entire plant is an important fodder. It can be used green, dried or as silage. For silage the leaves and stems are cut into small pieces and placed in silos. Here a slight fermentation occurs and the resulting produce is more palatable for cattle. Stover, the residue after the ears have been removed, is also fed to cattle or used for silage.
Although Maize is an important food in Neotropical America, it is not widely used as food in the rest of the world. Cornmeal is a poor breadstuff, owing to the absence of gluten, and corn bread is very crumbly and cannot be baked in loaves. The meal was first prepared by merely pounding the grain. Later millstones were used and now a milling process involving the use of rollers has been substituted. The whole grain was formerly used in milling, but the fatty oil, present in the embryo, gave an unpleasant odor and taste to the meal. In modern processes the embryo and hull are removed. Both white and yellow meals are milled. Cornmeal has many uses in other countries and in the southern United States. When boiled with water it becomes mush or hasty pudding, the Italian polenta. It is often baked in cakes such as Johnny Cakes, ashcakes, hoecakes, corn pone, and the Mexican tortillas. For corn bread the meal is mixed with wheat or rye flour. Scrapple is cornmeal that has been boiled with scraps of pork, liver and kidney and then seasoned and fried. Hominy or samp and hulled corn are prepared by soaking the grains in the lye of wood ashes to remove the hull and them cooking until soft. Small portions of the hard endosperm obtained during the milling process constitute hominy grits. The grain is also used in the preparation of many breakfast foods. In North America much maize on the cob is eaten, and sweet corn is extensively canned.
Industrial uses of maize and maize products have steadily increased in importance. The manufacture of cornstarch and its derivatives, glucose or corn syrup, corn sugar, dextrins and industrial alcohol and the production and uses of corn oil obtained from the embryo are important commodities. The grain is used for making various alcoholic beverages and the fibers in the stalks have been sued for making paper and yarn. The pith can be made into explosives or light packing material. The inner husks are for cigarette papers and the cobs are for fuel, smoking pork products, and as a source of charcoal and furfural, the latter a raw material used in making solvents, explosives, plastics, synthetic rubber and nylon. Zein, the protein in maize, can be made into artificial fibers with good tensile strength and wool like properties. Ethanol is not a common ingredient in gasoline in North America.
Usually the United States produces nearly one-half of the world’s supply of maize. Iowa and Illinois are the leading states, but through irrigation other states have begun to produce it also and various amounts are grown in every other state as well.
The utilization of hybrid maize has greatly increased the production. Crossing two carefully selected superior inbred strains produces hybrid seed. The first generation single crosses are uniform in size like the parents, but the ears are small. They are especially suited for the production of sweet-corn seed. Double-cross hybrids that result from the combination of two single crosses, are exceptionally vigorous and produce larger uniform ears with from 15-20 percent more kernels. The yield from hybrid seed is increased from 5-15 bushels per acre. The raising of hybrid corn and the production of the seeds has become an important enterprise.
In order or amount produced the United States leads the world followed by China, Argentina, Brazil, India, Mexico, South Africa, Italy and Russia.
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Rice, Oryza sativa, replaces all other cereals in tropical countries as the staff of life and dominates the economic and social structure. Over half the world’s populations find rice as an indispensable food. Over 95 % of the world crop is produced in the Orient.
Rice cultivation extends back into the ancient past with no authentic records as to when it started. The plant originated somewhere in Southeastern Asia, but it has spread to every warm region of the world. The history of rice and the history of China are closely tied. Rice was first cultivated in China with records going back further than 2,000 B.C. In classical Chinese the words for agriculture and rice culture are synonymous. This indicates that rice was the dominant crop at the time the language was taking form. In other languages the words for rice and food are identical. Rice was introduced into India before the time of the Greeks and very early reached Syria and Northern Africa. The first rice was grown in Europe in 1468 in Italy. The first rice grown in America was in South Carolina in 1694 from seed brought from Madagascar.
Rice is a large annual grass that grows to a height of from 2-4 ft. Instead of bearing an ear, rice produces a panicle, an inflorescence composed of a number of fine branches, each terminating in a single grain surrounded by a husk. The grains are easily detached together with this brown husk. In this condition it is known as paddy. Innumerable varieties of rice have been developed. These differ in the color, shape, size, flavor and other traits of the grain. One of these types contains a sugary substance instead of starch, which forms a soft, sticky palatable mass on boiling. Other species of Oryza occur as wild plants in the tropics of both hemispheres.
Rice prefers a climate where the average summer temperature does not go below 77 deg. Fahrenheit. It grows best on damp soils underlain with semi-impervious subsoil in places where it can be flooded. The delta and flood plains of the monsoon region are especially favorable. One type of rice, the upland or hill rice may be grown without irrigation. This kind had been preferred in Central and South America. Elsewhere the lowland rice that requires flooding during part of its development, is grown almost exclusively. Rice culture in wet areas is similar worldwide. In many countries primitive methods of agriculture are used. In developed countries rice cultivation has had a remarkable expansion.
The fields are plowed or hoed and the rice is sown broadcast or transplanted from seedbeds when 9-10 in. high. The young plants are covered with water, at first only at night, but later continuously, and the water is kept circulating. Upon ripening the water is drawn off and the fields are allowed to dry out. Rice is harvested in a manner similar to wheat and the stalks are stacked up to dry. There may be two or three crops a year. In the United States rice production is wholly mechanized.
Rice grains are removed by threshing or by drawing the stalks through narrow slits. When used directly for daily consumption the rice is left in the “paddy” condition because it stores better that way. The grains are husked just before they are to be used, and they are then pounded in a mortar with a wooden mallet and winnowed. The resulting grain is very nutritious for it contains considerable protein and fat as well as starch.
For commercial preparation of rice, the impurities are removed and the paddy is passed between millstones to break up the husk. Blowers remove the chaff. The grain is then pounded in huge mortars and a portion of the bran layer and embryo is removed. The waste is known as rice bran. The white rice is then scoured by friction and polished and a coating of glucose, talk or chalk is added. During these last processes the outer, more nutritive parts of the grain are removed. The rice polish that is left as a residue is twice as nutritious as the finished product.
Rice is used mainly as a food by over half the world’s population. It needs to be supplemented by legumes or some other food rich in proteins. A diet of rice and soybeans constitutes the food of millions of people in Asia. The polished rice, which reaches the world markets, is much less nutritious, but its use is widespread. Rice hulls and rice polish are valuable as livestock feed. The straw may be plaited and made into hats, shoes and other articles. Rice starch is widely used in Europe. Intoxicating beverages are made from rice in Japan and other areas.
China continues to produce most of the world’s rice, followed by India and Pakistan. Other important countries that produce rice are Japan, Java, Vietnam, Thailand, Burma, Brazil, Korea and the Philippines. The United States produces a substantial amount in the southeastern States and California. Rice is also grown in Egypt and Africa while Italy leads the European production.