Maize (
Zea mays L. ssp.
mays, pronounced
/ˈmeɪz/; from
Spanish:
maíz after
Taino mahiz,) known in many
English-speaking countries as
corn or
mielie/mealie, is a
grain domesticated by
indigenous peoples in
Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable or starch. The
Olmec and
Mayans cultivated it in numerous varieties throughout central and southern
Mexico, cooked, ground or processed through
nixtamalization. Between 1700 and 1250 BCE, the crop spread through much of the
Americas. The region developed a trade network based on surplus and varieties of maize crops. After
European contact with the Americas in the late 15th and early 16th centuries, explorers and traders carried maize back to Europe and introduced it to other countries. Maize spread to the rest of the world due to its ability to grow in diverse climates. Sugar-rich varieties called
sweet corn are usually grown for fresh consumption while
field-corn varieties are used for animal feed and as chemical feedstocks.
Maize is the most widely grown
crop in the Americas with 332 million
metric tons grown annually in the
United States alone (although 40% of the crop - 130 million tons - is used for corn ethanol.
[1])
Transgenic maize made up 85% of the maize planted in the United States in 2009.
[2] While some maize varieties grow to 12 metres (39 ft) tall,
[3] most commercially grown maize has been bred for a standardized height of 2.5 metres (8.2 ft). Sweet corn is usually shorter than field-corn varieties.
Naming conventions
Many small male flowers make up the male inflorescence, called the tassel
The term "maize" derives from the Spanish form of the indigenous
Taino word
maiz for the plant. This was the term used in the
United Kingdom and
Ireland, where it is now usually called "sweet corn", the most common form of the plant known to people there. Sweet corn is harvested earlier and eaten as a vegetable rather than a grain.
[4]
Outside the
British Isles, another common term for maize is "corn". This was originally the English term for any
cereal crop. In North America, its meaning has been restricted since the 19th century to maize, as it was shortened from "Indian corn."
[5] The term Indian corn now refers specifically to multi-colored "field corn" (
flint corn) cultivars.
[5]
In scientific and formal usage, "maize" is normally used in a global context. Equally, in bulk-trading contexts, "corn" is used most frequently. In the UK,
Australia and other English-speaking countries, the word "corn" is often used in culinary contexts, particularly in naming products such as
popcorn and
corn flakes. Though it should be noted that within the United States, the term "maize" is almost totally unheard of. "Maize" is used in agricultural and scientific references.
[Note 1]
In
Southern Africa, maize is commonly referred to as
mielie or
mealie, from the Portuguese
milho.
[6] Mielie-meal is the ground form.
Structure and physiology
Female inflorescence, with young silk
Maize stems superficially resemble
bamboo canes and the
internodes can reach 44.5 centimetres (17.5 in). Maize has a distinct growth form; the lower leaves being like broad flags, generally 50–100 centimetres long and 5–10 centimetres wide (2–4 ft by 2–4 in); the stems are erect, conventionally 2–3 metres (7–10 ft) in height, with many
nodes, casting off flag-leaves at every node. Under these leaves and close to the stem grow the ears. They grow about 3 millimetres a day.
The ears are female
inflorescences, tightly covered over by several layers of leaves, and so closed-in by them to the stem that they do not show themselves easily until the emergence of the pale yellow silks from the leaf whorl at the end of the ear. The silks are elongated
stigmas that look like tufts of hair, at first green, and later red or yellow. Plantings for
silage are even denser, and achieve a lower percentage of ears and more plant matter. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "
baby corn" used as a vegetable in
Asian cuisine.
Maize is a
facultative long-night plant and flowers in a certain number of
growing degree days >
50 °F (10 °C) in the environment to which it is adapted.
[7] The magnitude of the influence that long nights have on the number of days that must pass before maize
flowers is genetically prescribed and regulated by the
phytochrome system.
[8] Photoperiodicity can be eccentric in tropical
cultivars, while the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for
biofuels.
[9]
The apex of the stem ends in the tassel, an
inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel
dehisce and release pollen. Maize pollen is
anemophilous (dispersed by wind) and because of its large settling velocity most pollen falls within a few meters of the tassel. Each silk may become pollinated to produce one kernel of maize. Young ears can be consumed raw, with the
cob and silk, but as the plant matures (usually during the summer months) the cob becomes tougher and the silk dries to inedibility. By the end of the
growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water. Modern farming techniques in
developed countries usually rely on dense planting, which produces one large ear per stalk.
Seeds
The kernel of maize has a
pericarp of the fruit fused with the seed coat, typical of the
grasses, and the entire kernel is often referred to as the
seed. The cob is close to a
multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of
peas, and adhere in regular rows round a white pithy substance, which forms the ear. An ear contains from 200 to 400 kernels, and is from 10–25 cm (4–10 in) in length. They are of various colors: blackish,
bluish-gray, purple, green, red, white and yellow. When ground into
flour, maize yields more flour, with much less
bran, than wheat does. However, it lacks the protein
gluten of wheat and, therefore, makes baked goods with poor rising capability.
A
genetic variant that accumulates more sugar and less
starch in the ear is consumed as a
vegetable and is called
sweet corn.
Immature maize shoots accumulate a powerful antibiotic substance,
DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one). DIMBOA is a member of a group of
hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests including insects,
pathogenic fungi and
bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to be attacked by
aphids and
fungi. DIMBOA is also responsible for the relative resistance of immature maize to the
European corn borer (family
Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.
Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.
[10]
Genetics
Exotic varieties of maize are collected to add
genetic diversity when selectively breeding new domestic strains.
Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each had:
- Flour corn — Zea mays var. amylacea
- Popcorn — Zea mays var. everta
- Dent corn — Zea mays var. indentata
- Flint corn — Zea mays var. indurata
- Sweet corn — Zea mays var. saccharata and Zea mays var. rugosa
- Waxy corn — Zea mays var. ceratina
- Amylomaize — Zea mays
- Pod corn — Zea mays var. tunicata Larrañaga ex A. St. Hil.
- Striped maize — Zea mays var. japonica
This system has been replaced (though not entirely displaced) over the last 60 years by multi-variable classifications based on ever more data.
Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic,
cytological, protein and DNA evidence was added. Now the categories are forms (little used), races, racial complexes, and recently branches.
Maize has 10
chromosomes (n=10). The combined length of the chromosomes is 1500
cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive
heterochromatic domains that stain darkly. Individual knobs are
polymorphic among strains of both maize and
teosinte.
Barbara McClintock used these knob markers to validate her
transposon theory of "jumping genes", for which she won the 1983
Nobel Prize in Physiology or Medicine. Maize is still an important
model organism for genetics and
developmental biology today.
[11]
The Maize Genetics Cooperation Stock Center, funded by the USDA
Agricultural Research Service and located in the Department of Crop Sciences at the
University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g.,
tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at
MaizeGDB, the Maize Genetics and Genomics Database.
[12]
In 2005, the U.S.
National Science Foundation (NSF), Department of Agriculture (
USDA) and the
Department of Energy (DOE) formed a consortium to sequence the B73 maize
genome. The resulting DNA sequence data was deposited immediately into
GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site,
MaizeSequence.org.
Primary sequencing of the maize genome was completed in 2008.
[13] On November 20, 2009, the consortium published results of its sequencing effort in
Science.
[14] The genome, 85% of which is composed of
transposons, was found to contain 32,540 genes (By comparison, the
human genome contains about 2.9 billion bases and 26,000 genes). Much of the maize genome has been duplicated and reshuffled by
helitrons a group of rolling circle transposons.
[15]
Genetic modification
Genetically modified (GM) maize is one of the 11
GM crops grown commercially in 2009.
[16] Grown since 1997 in the United States and Canada, 85% of the US maize crop was genetically modified in 2009. It is also grown commercially in Brazil, Argentina,
South Africa, Canada, the Philippines, Spain and, on a smaller scale, in the
Czech Republic,
Portugal, Egypt and Honduras.
[2]
Origin
A
Tripsacum grass (big) and a teosinte (small)
Several theories have been proposed about the specific origin of maize in Mesoamerica:
[17][18]
- It may be a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.
- It may have been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.
- It may have undergone two or more domestications either of a wild maize or of a teosinte.
- It may have evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.)
In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of
Tripsacum, a related genus. However, the proposed role of
Tripsacum (gama grass) in the origins of maize has been refuted by modern
genetic testing, refuting Mangelsdorf’s model and the fourth listed above.
[17]:40
Guila Naquitz Cave, site of one of the oldest known remains of maize
The teosinte origin theory was proposed by the Russian botanist
Nikolai Ivanovich Vavilov in 1931 and the later American
Nobel Prize-winner
George Beadle in 1932.
[17]:10 Though it had experimental support, in particular for the ability of teosinte and maize to cross-breed and produce fertile offspring, it did not explain a number of problems, among them:
- how the immense diversity of the species of sect. Zea originated,
- how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and
- how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits earlier than the earliest known until recently, dating from ca. 1100 BC.
The
domestication of maize is of particular interest to researchers —
archaeologists,
geneticists,
ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between
Oaxaca and
Jalisco, because the oldest archaeological remains of maize known at the time were found there. Genetic studies led by
John Doebley identified
Zea mays ssp.
parviglumis, native to the Balsas River valley and also known as Balsas teosinte, as being the
crop wild relative teosinte genetically most similar to modern maize.
[19] However, archaeobotanical studies published in 2009 now point to the lowlands of the Balsas River valley, where stone milling tools with maize residue have been found in a 8,700-years old layer of deposits.
[20][21][22] Some of the earliest pollen remains from Latin America have been found in lake sediments from
tropics of southern Mexico and upper Central America, up to
Laguna Martinez and have been radiocarbon dated to around 4,700 years ago.
[citation needed] Archaeological remains of early maize ears, found at
Guila Naquitz Cave in the
Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near
Tehuacan, Puebla, date ca. 2750 BC. Little change occurred in ear form until ca. 1100 BC when great changes appeared in ears from Mexican caves: maize diversity rapidly increased and archaeological teosinte was first deposited.
Perhaps as early as 1500 BC, maize began to spread widely and rapidly. As it was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple (along with
squash, Andean region
potato,
quinoa,
beans, and
amaranth), of most
pre-Columbian North American,
Mesoamerican,
South American, and
Caribbean cultures. The Mesoamerican civilization was strengthened upon the field crop of maize; through harvesting it, its religious and spiritual importance and how it impacted their diet. Maize formed the Mesoamerican people’s identity. During the
1st millennium AD, maize cultivation spread from
Mexico into the
U.S. Southwest and during the following millennium into the
U.S. Northeast and southeastern
Canada, transforming the landscape as Native Americans cleared large forest and grassland areas for the new crop.
[citation needed]
It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small and hard to obtain to be eaten directly, as each kernel is enclosed in a very hard bi-valve shell. However, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn. Some have argued that it would have taken too many generations of
selective breeding in order to produce large compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest that this objection is not well founded.
In 2005, research by the
USDA Forest Service indicated that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States contributed to the decline of freshwater
mussels, which are very sensitive to environmental changes.
[23]
Production
Methods
Because it is cold-intolerant, in the
temperate zones maize must be planted in the spring. Its
root system is generally shallow, so the plant is dependent on soil moisture. As a C4 plant (a plant that uses
C4 carbon fixation), maize is a considerably more water-efficient crop than C3 plants (plants that use
C3 carbon fixation) like the small grains,
alfalfa and
soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the
United States, a good harvest was traditionally predicted if the maize was "knee-high by the
Fourth of July," although modern
hybrids generally exceed this growth rate. Maize used for
silage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage," after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field very late in the autumn in order to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of
Africa, where periodic
drought regularly causes
famine by causing maize crop failure.
Mature plants showing ears
Maize was planted by the
Native Americans in hills, in a complex system known to some as the
Three Sisters. Maize provided support for
beans, and the beans provided nitrogen derived from nitrogen-fixing
Rhizobia bacteria which live on the roots of beans and other
legumes; and
squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2.0–3.9 ft) apart was planted with 3 or 4 seeds, a method still used by home gardeners. A later technique was
checked maize where hills were placed 40 inches apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands this was altered and seeds were planted in the bottom of 10–12 cm (3.9–4.7 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations.
A maize heap at the harvest site,
India In North America, fields are often planted in a two-
crop rotation with a
nitrogen-fixing crop, often
alfalfa in cooler climates and
soybeans in regions with longer summers. Sometimes a third crop,
winter wheat, is added to the rotation.
Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been
genetically modified to tolerate
glyphosate or to provide protection against natural pests. Glyphosate (trade name Roundup) is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.
In midwestern United States, low-till or
no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and
fertilized. Weeds are controlled through the use of
herbicides, and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.
Before
World War II, most maize in North America was harvested by hand (as it still is in most of the other countries where it is grown). This involves a large numbers of workers and associated social events (husking or shucking
bees). Some one and two-row mechanical pickers were in use but the maize
combine was not adopted until after the War. By hand or mechanical picker, the entire ear is harvested which then requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in
corn cribs and these whole ears are a sufficient form for some livestock feeding use. Few modern farms store maize in this manner. Most harvest the grain from the field and store it in bins. The combine with a maize head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled in to a mangled pile on the ground. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates out the husk and the cob, keeping only the kernels.
Quantity
Worldwide maize production
Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. The United States produces 40% of the world's harvest; other top producing countries include
China,
Brazil,
Mexico,
Indonesia,
India,
France and
Argentina. Worldwide production was 817 million
tonnes in 2009—more than
rice (678 million
tonnes) or
wheat (682 million
tonnes).
[24] In 2009, over 159 million
hectares of maize were planted worldwide, with a yield of over 5 tonnes/
hectare. Production can be significantly higher in certain regions of the world; 2009 forecasts for production in Iowa were 11614 kg/ha.
[25][Note 2] "There is conflicting evidence to support the hypothesis that maize yield potential has increased" over the past few decades.
[26]
| Top ten maize producers in 2009 |
| Country | Production (tonnes) | Note |
 United States | 333,010,910 |
|
 China | 163,118,097 |
|
 Brazil | 51,232,447 |
|
 Mexico | 20,202,600 |
|
 Indonesia | 17,629,740 |
|
 India | 17,300,000 |
|
 France | 15,299,900 |
|
 Argentina | 13,121,380 |
|
 South Africa | 12,050,000 |
|
 Ukraine | 10,486,300 |
|
| World | 817,110,509 | [A] |
| No symbol = official figure, A = Aggregate (may include official, semi-official or estimates).[24] |
United States
In 2010, the maize planted area for all purposes in the US was estimated at 35 million hectares,
[27] following an increasing trend since 2008.
[28] About 14% of the harvested corn area is irrigated.
[29]
Pests
Insects
The susceptibility of maize to the European corn borer, and the resulting large crop losses, led to the development of
transgenic expressing the
Bacillus thuringiensis toxin. "Bt maize " is widely grown in the
United States and has been approved for release in
Europe.
Diseases
Uses
Human food
Maize and
cornmeal (ground dried maize) constitute a
staple food in many regions of the world. Introduced into
Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop.
[30] Maize meal is made into a thick
porridge in many cultures: from the
polenta of
Italy, the angu of
Brazil, the
mămăligă of
Romania, to
mush in the U.S. (called
grits in the South) or the food called
mealie pap in South Africa and
sadza,
nshima and
ugali in other parts of Africa. Maize meal is also used as a replacement for
wheat flour, to make
cornbread and other baked products.
Masa (cornmeal treated with
lime water) is the main ingredient for
tortillas,
atole and many other dishes of
Mexican food.
Popcorn consists of kernels of certain varieties that explode when heated, forming fluffy pieces that are eaten as a snack. Roasted dried maize cobs with semi-hardened kernels, coated with a seasoning mixture of fried chopped spring onions with salt added to the oil, is a popular
snack food in Vietnam. Cancha, which are roasted maize chulpe kernels, are a very popular snack food in Peru, and also appears in traditional Peruvian
ceviche. An unleavened bread called
Makki di roti is a popular bread eaten in the
Punjab region of India and Pakistan.
Chicha and "chicha morada" (purple chicha) are drinks typically made from particular types of maize. The first one is fermented and alcoholic, the second is a soft drink commonly drunk in Peru.
Corn flakes are a common
breakfast cereal in North America and the United Kingdom, and found in many other countries all over the world.
Maize can also be prepared as
hominy, in which the kernels are soaked with
lye in a process called
nixtamalization; or
grits, which are coarsely ground hominy. These are commonly eaten in the
Southeastern United States, foods handed down from
Native Americans, who called the dish
sagamite.
The Brazilian dessert
canjica is made by boiling maize kernels in sweetened milk. Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob.
Sweetcorn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such
corn on the cob is a common dish in the United States, Canada, United Kingdom,
Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries. Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors of hot-dog carts, churro wagons, and fruit stands seen on the streets of big cities today.
[31] The cooked unripe kernels may also be shaved off the cob and served as a
vegetable in side dishes,
salads,
garnishes, etc. Alternatively, the raw unripe kernels may also be grated off the cobs and processed into a variety of cooked dishes, such as maize
purée,
tamales,
pamonhas,
curau,
cakes,
ice creams, etc.
A roadside vendor selling steamed maize in
India Maize is a major source of
starch.
Cornstarch (maize flour) is a major ingredient in home cooking and in many industrialized food products. Maize is also a major source of
cooking oil (
corn oil) and of maize gluten. Maize starch can be
hydrolyzed and enzymatically treated to produce syrups, particularly high fructose
corn syrup, a sweetener; and also fermented and distilled to produce
grain alcohol. Grain alcohol from maize is traditionally the source of
bourbon whiskey. Maize is sometimes used as the starch source for
beer. Within the United States, the usage of maize for human consumption constitutes about 1/40th of the amount of grown in the country. In the United States and Canada maize is mostly grown to feed for
livestock, as forage,
silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products, such as
dog food.
Maize is also used as a
fish bait, called "dough balls". It is particularly popular in
Europe for
coarse fishing.
Alternative medicine
Stigmas from female maize flowers, popularly called
corn silk, are sold as
herbal supplements.
Chemicals
Starch from maize can also be made into
plastics,
fabrics,
adhesives, and many other chemical products.
The
corn steep liquor, a plentiful watery byproduct of maize
wet milling process, is widely used in the
biochemical industry and research as a culture medium to grow many kinds of
microorganisms.
[32]
Biofuel
"Feed maize" is being used increasingly for heating;
[citation needed] specialized
corn stoves (similar to
wood stoves) are available and use either feed maize or wood pellets to generate heat. Maize cobs are also used as a
biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or
cherry pits) into the fire.
Maize is increasingly used as a feedstock for the production of
ethanol fuel.
[citation needed] Ethanol is mixed with gasoline in order to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid 2007 led to higher demand for ethanol, which in turn lead to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.
[citation needed]
The price of food is affected to a certain degree by the use of maize for biofuel production. The cost of transportation, production, and marketing are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The effect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This in turn results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.
[33][34]
Farm-based maize silage digester located near
Neumünster in Germany, 2007. Green inflatable biogas holder is shown on top of the digester
Maize is widely used in
Germany as a feedstock for
biogas plants. Here the maize is harvested, shredded then placed in
silage clamps from which it is fed into the biogas plants. This process makes use of the whole plant rather than simply utilizing the cob as in the production of fuel ethanol.
A
biomass gasification power plant in Strem near
Güssing,
Burgenland,
Austria began in 2005. Research is being done to make
diesel out of the biogas by the
Fischer Tropsch method.
Increasingly ethanol is being used at low concentrations (10% or less) as an additive in
gasoline (
gasohol) for motor fuels to increase the
octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "
biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of
NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multi-million dollar subsidies and other government supports. (...) According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers.").
[35] However, introduction in the northern latitudes of the U.S. of
tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.
As a result of the
U.S. federal government announcing its production target of 35 billion gallons of
biofuels by 2017, ethanol production will grow to 7 billion gallons by 2010, up from 4.5 billion in 2006, boosting ethanol's share of maize demand in the U.S. from 22.6 percent to 36.1 percent.
[36]
Ornamental and other uses
Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used. Size-superlative types, having reached 34 ft (10 m) tall, cobs 2 ft (61 cm) long, or 1 in (2.5 cm) kernels, have been popular for at least a century.
[37][38] Corncobs can be hollowed out and treated to make inexpensive
smoking pipes, first manufactured in the United States in 1869.
Children playing in a maize kernel box
An unusual use for maize is to create a
corn maze (or
maize maze) as a tourist attraction. The idea of a maize maze was introduced by
Adrian Fisher, one of the most prolific designers of modern mazes, with The American Maze Company who created a maze in
Pennsylvania in 1993. Traditional mazes are most commonly grown using
yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using
GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the U.S., these are popular in many farming communities.
Maize kernels can be used in place of sand in a
sandboxlike enclosure for children's play.
[39]
Additionally feed corn is sometimes used by hunters to bait animals such as deer or wild hogs.
Fodder
Maize makes a greater quantity of
epigeous mass than other
cereal plants, so can be used for
fodder. Digestibility and palatability are higher when ensiled and fermented, rather than dried.
As a commodity
Maize as a commodity is bought and sold by investors and price speculators as a tradable commodity. It is referred to as a corn
futures contract. Corn futures contracts are traded on the Chicago Board of Trade (CBOT) under
ticker symbol C. They are delivered every year in March, May, July, September, and December.
[40]
U.S. usage breakdown
The breakdown of usage of the 12.1 billion bushel 2008 U.S. maize crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.
[41]
- 5,250 million bu. - Livestock feed
- 3,650 million bu. - Ethanol production
- 1,850 million bu. - Exports
- 943 million bu. - Production of Starch, Corn Oil, Sweeteners (HFCS,etc.)
- 327 million bu. - Human consumption - grits, corn flour, corn meal, beverage alcohol
Comparison to other staple foods
Synopsis[42] of
Staple food ~composition: | Amaranth
[Note 3] | Wheat
[Note 4] | Rice
[Note 5] | Sweetcorn
[Note 6] | Potato
[Note 7] |
| Component (per 100g portion) | Amount | Amount | Amount | Amount | Amount |
| water (g) | 11 | 11 | 12 | 76 | 82 |
| energy (kJ) | 1554 | 1506 | 1527 | 360 | 288 |
| protein (g) | 14 | 23 | 7 | 3 | 1.7 |
| fat (g) | 7 | 10 | 1 | 1 | 0.1 |
| carbohydrates (g) | 65 | 52 | 79 | 19 | 16 |
| fiber (g) | 7 | 13 | 1 | 3 | 2.4 |
| sugars (g) | 1.7 | 0.1 | >0.1 | 3 | 1.2 |
| iron (mg) | 7.6 | 6.3 | 0.8 | 0.5 | 0.5 |
| manganese (mg) | 3.4 | 13.3 | 1.1 | 0.2 | 0.1 |
| calcium (mg) | 159 | 39 | 28 | 2 | 9 |
| magnesium (mg) | 248 | 239 | 25 | 37 | 21 |
| phosphorus (mg) | 557 | 842 | 115 | 89 | 62 |
| potassium (mg) | 508 | 892 | 115 | 270 | 407 |
| zinc (mg) | 2.9 | 12.3 | 1.1 | 0.5 | 0.3 |
| panthothenic acid (mg) | 1.5 | 0.1 | 1.0 | 0.7 | 0.3 |
| vitB6 (mg) | 0.6 | 1.3 | 0.2 | 0.1 | 0.2 |
| folate (µg) | 82 | 281 | 8 | 42 | 18 |
| thiamin (mg) | 0.1 | 1.9 | 0.1 | 0.2 | 0.1 |
| riboflavin (mg) | 0.2 | 0.5 | >0.1 | 0.1 | >0.1 |
| niacin (mg) | 0.9 | 6.8 | 1.6 | 1.8 | 1.1 |
Hazards
Pellagra
When maize was first introduced into other farming systems than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a
staple food. This was a mystery since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food.
[43]
It was eventually discovered that the indigenous Americans had learned to soak maize
[citation needed] in
alkali-water—made with ashes and lime (
calcium oxide) by
Mesoamericans and North Americans—which liberates the B-vitamin
niacin, the lack of which was the underlying cause of the condition known as
pellagra. This alkali process is known by its
Nahuatl (Aztec)-derived name:
nixtamalization. Besides the lack of niacin, pellagra was also characterized by
protein deficiency, a result of the inherent lack of two key
amino acids in pre-modern maize,
lysine and
tryptophan. Nixtamalisation was also found to increase the availability of lysine and tryptophan to some extent, but more importantly, the indigenous Americans had also learned to balance their consumption of maize with
beans and other protein sources such as
amaranth and
chia, as well as meat and fish, in order to acquire the complete range of amino acids for normal
protein synthesis.
Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century pellagra reached epidemic proportions in parts of the southern U.S., as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. In 1914 the U.S. government officially endorsed the germ theory of pellagra, but rescinded this endorsement several years later when the evidence grew against it. By the mid-1920s the deficiency theory of pellagra was becoming
scientific consensus, and the theory was validated in 1932 when niacin deficiency was determined to be the cause of the illness.
Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet has also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize.
[44]
Allergy
Maize contains
lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied
allergy to maize in humans.
[45] The allergic reaction can cause skin rash, swelling or itching of
mucous membranes, diarrhea, vomiting,
asthma and, in severe cases,
anaphylaxis. It is unclear how common this allergy is in the general population.
In art
Maize has been an essential crop in the
Andes since the
pre-Columbian Era. The
Moche culture from Northern
Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize represented anthropomorphically as well as naturally.
[46]
In the United States, maize ears along with tobacco leaves are carved into the capitals of columns in the
U.S. Capitol building. Maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate the fall season, local agricultural productivity and culture. Bundles of dried maize stalks are often displayed often along with pumpkins, gourds and straw in autumnal displays outside homes and businesses. A well-known example of architectural use is the
Corn Palace in Mitchell, South Dakota, which utilizes cobs of colored maize to implement a mural design that is recycled annually.
A maize stalk with two ripe cobs is depicted on the
reverse of the Croatian 1
lipa coin, minted since 1993.
[47]
Nasihat Luqman Kepada Anaknya
