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Maize: Difference between revisions
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''Maize'' is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region.<ref name="Ensminger">{{cite book | title=Foods and Nutrition Encyclopedia, 2nd ed. | publisher=CRC Press |last=Ensminger |first=Audrey H. | year=1994 | isbn=0-8493-8980-1 | page=[{{google books |plainurl=y |id=XMA9gYIj-C4C|page=479}} 479] | quote=The word "maize" is preferred in international usage because in many countries the term "corn", the name by which the plant is known in the United States, is synonymous with the leading cereal grain; thus, in England "corn" refers to wheat, and in Scotland and Ireland it refers to oats.}}</ref> ''Maize'' is used by agricultural bodies and [[research institute]]s such as the [[FAO]] and [[CSIRO]]. National agricultural and industry associations often include the word ''maize'' in their name even in English-speaking countries where the local, informal word is something other than ''maize''; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association. However, in commodities trading, ''corn'' consistently refers to maize and not other grains.{{citation needed|date=July 2013}} | ''Maize'' is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region.<ref name="Ensminger">{{cite book | title=Foods and Nutrition Encyclopedia, 2nd ed. | publisher=CRC Press |last=Ensminger |first=Audrey H. | year=1994 | isbn=0-8493-8980-1 | page=[{{google books |plainurl=y |id=XMA9gYIj-C4C|page=479}} 479] | quote=The word "maize" is preferred in international usage because in many countries the term "corn", the name by which the plant is known in the United States, is synonymous with the leading cereal grain; thus, in England "corn" refers to wheat, and in Scotland and Ireland it refers to oats.}}</ref> ''Maize'' is used by agricultural bodies and [[research institute]]s such as the [[FAO]] and [[CSIRO]]. National agricultural and industry associations often include the word ''maize'' in their name even in English-speaking countries where the local, informal word is something other than ''maize''; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association. However, in commodities trading, ''corn'' consistently refers to maize and not other grains.{{citation needed|date=July 2013}} | ||
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== Breeding == | |||
[[File:Field, corn, Liechtenstein, Mountains, Alps, Vaduz, sky, clouds, landscape.jpg|thumb|right|Field of maize in [[Liechtenstein]]]] | |||
Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used. | |||
Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful developing Reid's Yellow Dent in the 1860s. These early efforts were based on [[Selection methods in plant breeding based on mode of reproduction|mass selection]]. Later breeding efforts included ear to row selection, (C. G. Hopkins ca. 1896), hybrids made from selected [[inbred]] lines (G. H. Shull, 1909), and the highly successful double cross hybrids using 4 inbred lines ([[Donald F. Jones|D. F. Jones]] ca. 1918, 1922). University supported breeding programs were especially important in developing and introducing modern hybrids. (Ref Jugenheimer Hybrid Maize Breeding and Seed Production pub. 1958) by the 1930s, companies such as [[Pioneer Hi-Bred|Pioneer]] devoted to production of hybrid maize had begun to influence long term development. Internationally important seed banks such as [[International Maize and Wheat Improvement Center]] (CIMMYT) and the US bank at Maize Genetics Cooperation Stock Center [[University of Illinois at Urbana-Champaign]] maintain [[germplasm]] important for future crop development. | |||
Since the 1940s the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic modification have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer.<ref name=nyt14 /> There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.<ref>{{cite journal | doi = 10.2135/cropsci1999.3961622x | author = Duvick, D. N. & Cassman, K. G. | title = Post-green-revolution trends in yield potential of temperate maize in the north-central United States | journal = [[Crop Science (journal)|Crop Science]] | volume = 39 | pages = 1622–1630 | year = 2009 | url = http://crop.scijournals.org/cgi/content/abstract/39/6/1622 | issue = 6 | deadurl = yes | archiveurl = https://web.archive.org/web/20091115003659/http://crop.scijournals.org/cgi/content/abstract/39/6/1622 | archivedate = November 15, 2009 | df = mdy-all }}</ref> | |||
== Cultivation == | |||
=== Planting === | |||
[[File:Plàntules moresc 2012.JPG|thumb|Seedlings three weeks after sowing]] | |||
[[File:Corn Zea mays Plant Row 2000px.jpg|right|thumb|upright|Young stalks]] | |||
Because it is cold-intolerant, in the [[Temperate|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 were "knee-high by the [[Independence Day (United States)|Fourth of July]]", although modern [[Hybrid (biology)|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 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 maize crop failure and consequent [[famine]]. Although it is grown mainly in wet, hot climates, it has been said to thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.<ref>Fernandez-Armesto, Felipe (2011). "The World: A History", p. 470. Penguin Academics, London. {{ISBN|0-205-75930-0}}</ref> | |||
[[File:Maispflanze.jpg|left|thumb|upright|Mature plants showing ears]] | |||
Maize was planted by the [[Native American (Americas)|Native Americans]] in hills, in a complex system known to some as the [[Three Sisters (agriculture)|Three Sisters]]. Maize provided support for [[bean]]s, and the beans provided nitrogen derived from nitrogen-fixing [[rhizobia]] bacteria which live on the roots of beans and other [[legume]]s; and [[Squash (fruit)|squashes]] provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil.<ref name=Mann_2011>{{cite book |title=[[1491: New Revelations of the Americas Before Columbus]] |edition=2nd |authorlink=Charles C. Mann |first=Charles C. |last=Mann |chapter=Cotton (or Anchovies) and Maize |pages=225–229 |date=July 2011 |publisher=[[Vintage Books]] |isbn=978-1-4000-3205-1 |location=New York}}</ref> This method was replaced by single species hill planting where each hill {{convert|60|–|120|cm|ft|abbr=on}} apart was planted with three or four seeds, a method still used by home gardeners. A later technique was "checked maize", where hills were placed {{convert|40|in|m|abbr=on}} 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 {{convert|10|–|12|cm|in|abbr=on}} 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. When maize is planted in rows, it also allows for planting of other crops between these rows to make more efficient use of land space.<ref>{{cite web|last1=Diderot|first1=Denis|title=Maize|url=http://quod.lib.umich.edu/d/did/did2222.0002.667/--maize?rgn=main;view=fulltext;q1=Agriculture|website=The Encyclopedia of Diderot & d'Alembert: Collaborative Translations Project|accessdate=April 1, 2015}}</ref> | |||
In most regions today, maize grown in residential [[garden]]s is still often planted manually with a [[hoe (tool)|hoe]], whereas maize grown commercially is no longer planted manually but rather is planted with a [[planter (farm implement)|planter]]. In North America, fields are often planted in a two-[[crop rotation]] with a [[Nitrogen fixation|nitrogen-fixing]] crop, often [[alfalfa]] in cooler climates and [[soybean]]s 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 is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature. | |||
In the 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 [[anhydrous ammonia|fertilized]]. [[Weed]]s are controlled through the use of [[herbicide]]s, 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. | |||
=== Harvesting === | |||
[[File:YellowCorn.jpg|thumb|right|Mature maize ears]] | |||
[[File:Iowa harvest 2009.jpg|thumb|right|Harvesting maize, [[Jones County, Iowa]]]] | |||
Before the 20th century, all maize harvesting was by [[manual labour]], by [[grazing]], or by some combination of those. Whether the ears were hand-picked and the [[corn stover|stover]] was grazed, or the whole plant was cut, gathered, and [[stook|shocked]], people and [[livestock]] did all the work. Between the 1890s and the 1970s, the technology of maize harvesting expanded greatly. Today, all such technologies, from entirely manual harvesting to entirely mechanized, are still in use to some degree, [[appropriate technology|as appropriate to each farm's needs]], although the thoroughly mechanized versions predominate, as they offer the lowest [[unit cost]]s when scaled to large farm operations. For small farms, their unit cost can be too high, as their higher [[fixed cost]] cannot be [[amortization|amortized]] over as many units. | |||
Before [[World War II]], most maize in North America was harvested by hand. This involved a large numbers of workers and associated social events (husking or shucking [[communal work|bees]]). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the [[corn stover|stover]]) and corn binders, which are [[reaper-binder]]s designed specifically for maize (for example, {{YouTube|zA3zbJNvWuo}}). The latter produce [[sheaf (agriculture)|sheaves]] that can be [[stook|shocked]]. 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 crib]]s, and these whole ears are a sufficient form for some livestock feeding use. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a [[combine harvester|combine]] and store it in [[silo#Bins|bins]]. The combine with a corn 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 into a mangled pile on the ground, where it usually is left to become [[organic matter]] for the [[soil]]. 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. | |||
When maize is a [[silage]] crop, the entire plant is usually chopped at once with a [[forage harvester]] (chopper) and ensiled in silos or polymer wrappers. Ensiling of sheaves cut by a corn binder was formerly common in some regions but has become uncommon. | |||
[[File:MaizeYield.png|thumb|right|Worldwide maize production]] | |||
For storing grain in bins, the moisture of the grain must be sufficiently low to avoid spoiling. If the moisture content of the harvested grain is too high, [[grain drying|grain dryers]] are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases ([[propane]] or [[natural gas]]) and electricity to power the blowers.<ref>{{cite web|last=Van Devender|first=Karl|title=Grain Drying Concepts and Options|publisher=University of Arkansas Division of Agriculture|date=July 2011|url=http://www.uaex.edu/publications/pdf/FSA-1072.pdf|accessdate=December 15, 2013}}</ref> | |||
== References == | |||
{{Reflist|30em}} | |||
== Further reading == | |||
* {{cite book|author1=Aureliano Brandolni |author2=Andrea Brandolini |title=Il mais in Italia: storia naturale e agricola|quote= XII+370 pages and 80 colour pages|publisher= CRF press|location= Bergamo, Italy|year= 2006|url=http://www.asa-press.com/l-mais.html}} | |||
* Clampitt, Cynthia. ''Maize: How Corn Shaped the U.S. Heartland'' (2015) | |||
* {{cite web|author1=Ferro, D.N. |author2=Weber, D.C. |lastauthoramp=yes |url=http://www.eap.mcgill.ca/CPMP_1.htm|title= Managing Sweet Corn Pests in Massachusetts}} | |||
* {{cite book|first=Duccio |last=Bonavia|title=Maize: Origin, Domestication, and Its Role in the Development of Culture|url={{google books |plainurl=y |id=TciIlddPBasC}}|date=13 May 2013|publisher=Cambridge University Press|isbn=978-1-107-02303-1}} | |||
== External links == | |||
* [http://www.maizegdb.org/ Maize Genetics and Genomics Database] | |||
* [http://maizecoop.cropsci.uiuc.edu/ Maize Genetics Cooperation Stock Center] | |||
[[Category:Maize| ]] | |||
