Editing Wheat (section)

== Agronomy ==

=== Growing wheat ===

Wheat is an [[Annual plant|annual]] crop. It can be planted in autumn and harvested in early summer as [[winter wheat]] in climates that are not too severe, or planted in spring and harvested in autumn as spring wheat. It is normally planted after [[Tillage|tilling]] the soil by [[plough]]ing and then [[harrowing]] to kill weeds and create an even surface. The seeds are then scattered on the surface, or [[seed drill|drilled]] into the soil in rows. Winter wheat lies dormant during a winter freeze. It needs to develop to a height of 10 to 15&nbsp;cm before the cold intervenes, so as to be able to survive the winter; it requires a period with the temperature at or near freezing, its [[dormancy]] then being broken by the thaw or rise in temperature. Spring wheat does not undergo dormancy. Wheat requires a deep [[soil]], preferably a [[loam]] with organic matter, and available minerals including soil nitrogen, phosphorus, and potassium. An acid and [[peat]]y soil is not suitable. Wheat needs some 30 to 38&nbsp;cm of rain in the growing season to form a good crop of grain.<ref name="EOS-2023"/>

The farmer may intervene while the crop is growing to add [[fertilizer]], water by [[irrigation]], or pesticides such as [[herbicide]]s to kill broad-leaved weeds or [[insecticide]]s to kill insect pests. The farmer may assess soil minerals, soil water, weed growth, or the arrival of pests to decide timely and cost-effective corrective actions, and crop ripeness and water content to select the right moment to harvest. Harvesting involves [[reaping]], cutting the stems to gather the crop; and [[threshing]], breaking the ears to release the grain; both steps are carried out by a [[combine harvester]]. The grain is then dried so that it can be stored safe from [[mould]] fungi.<ref name="EOS-2023">{{cite web |title=How To Grow Wheat Efficiently On A Large Farm |website=EOS Data Analytics |date=10 May 2023 |url=https://eos.com/blog/growing-wheat/ |access-date=23 December 2023}}</ref>

=== Crop development ===

[[File:Wheat developmental stages.tif|thumb|upright=1.75|center|Wheat developmental stages on the [[BBCH-scale|BBCH]] and Zadok's scales]]

Wheat normally needs between 110 and 130 days between sowing and harvest, depending upon climate, seed type, and soil conditions. Optimal crop management requires that the farmer have a detailed understanding of each stage of development in the growing plants. In particular, spring [[fertilizer]]s, [[herbicide]]s, [[fungicide]]s, and [[Plant hormone|growth regulators]] are typically applied only at specific stages of plant development. For example, it is currently recommended that the second application of nitrogen is best done when the ear (not visible at this stage) is about 1&nbsp;cm in size (Z31 on [[Zadoks scale]]). Knowledge of stages is also important to identify periods of higher risk from the climate. Farmers benefit from knowing when the 'flag leaf' (last leaf) appears, as this leaf represents about 75% of photosynthesis reactions during the grain filling period, and so should be preserved from disease or insect attacks to ensure a good yield. Several systems exist to identify crop stages, with the [[Feekes scale|Feekes]] and Zadoks scales being the most widely used. Each scale is a standard system which describes successive stages reached by the crop during the agricultural season.<ref>{{cite book |last1=Slafer |first1=G.A. |last2=Satorre |first2=E.H. |year=1999 |title=Wheat: Ecology and Physiology of Yield Determination |publisher=Haworth Press |isbn=1-56022-874-1 |pages=322–323}}</ref> For example, the stage of pollen formation from the mother cell, and the stages between [[anthesis]] and maturity, are susceptible to high temperatures, and this adverse effect is made worse by water stress.<ref>{{cite journal |last1=Saini |first1=H.S. |last2=Sedgley |first2=M. |last3=Aspinall |first3=D. |year=1984 |title=Effect of heat stress during floral development on pollen tube growth and ovary anatomy in wheat (''Triticum aestivum'' L.) |journal=Australian Journal of Plant Physiology |volume=10 |issue=2 |pages=137–144 |doi=10.1071/PP9830137 }}</ref>

<gallery mode="packed" heights="150px">
File:WheatFlower1-rotated.jpg|[[Anthesis]] stage
File:Wheat Ear milk full.jpg|Late milk stage
Melissa Askew 2015-08-08 (Unsplash).jpg|Right before harvest
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=== Farming techniques ===

{{further|British agricultural revolution}}

Technological advances in soil preparation and seed placement at planting time, use of [[crop rotation]] and [[fertilizer]]s to improve plant growth, and advances in harvesting methods have all combined to promote wheat as a viable crop. When the use of [[seed drill]]s replaced broadcasting sowing of seed in the 18th century, another great increase in productivity occurred. Yields of pure wheat per unit area increased as methods of crop rotation were applied to land that had long been in cultivation, and the use of fertilizers became widespread.<ref>{{cite book |last=Overton |first=Mark |author-link=Mark Overton |title=Agricultural Revolution in England: The transformation of the agrarian economy 1500-1850 |url=https://archive.org/details/isbn_9780521568593 |url-access=registration |year=1996 |publisher=Cambridge University Press |isbn=978-0-521-56859-3 |page=1, and throughout}}</ref>

Improved agricultural husbandry has more recently included pervasive [[agricultural automation|automation]], starting with the use of [[threshing machine]]s,<ref>{{Cite journal |last1=Caprettini |first1=Bruno |last2=Voth |first2=Hans-Joachim |title=Rage against the Machines: Labor-Saving Technology and Unrest in Industrializing England |journal=American Economic Review: Insights |year=2020 |volume=2 |issue=3 |pages=305–320 |doi=10.1257/aeri.20190385 |s2cid=234622559 |doi-access=free}}</ref> and progressing to large and costly machines like the [[combine harvester]] which greatly increased productivity.<ref>{{cite book |title=A Century of Innovation: Twenty Engineering Achievements That Transformed Our Lives, Chapter 7, Agricultural Mechanization |last=Constable |first=George |author2=Somerville, Bob |year=2003 |publisher=Joseph Henry Press |location=Washington, DC |isbn=0-309-08908-5 |url= http://www.greatachievements.org/?id=2955}}</ref> At the same time, better varieties such as [[Norin 10 wheat]], developed in Japan in the 1930s,<ref>{{cite journal |last1=Borojevic |first1=Katarina |last2=Borojevic |first2=Ksenija |date=July–August 2005 |title=The Transfer and History of "Reduced Height Genes" (Rht) in Wheat from Japan to Europe |journal=[[Journal of Heredity]] |publisher=[[Oxford University Press]] |volume=96 |issue=4 |pages=455–459 |doi=10.1093/jhered/esi060 |pmid=15829727 |doi-access=free }}</ref> or the dwarf wheat developed by [[Norman Borlaug]] in the [[Green Revolution]], greatly increased yields.<ref name="Shindler-2016">{{cite web |last1=Shindler |first1=Miriam |title=From east Asia to south Asia, via Mexico: how one gene changed the course of history |url=https://www.cimmyt.org/news/from-east-asia-to-south-asia-via-mexico-how-one-gene-changed-the-course-of-history/ |website=CIMMYT |date=3 January 2016 |access-date=19 November 2021}}</ref><ref>{{cite journal |last=Brown |first=L. R. |title=Nobel Peace Prize: developer of high-yield wheat receives award (Norman Ernest Borlaug) |journal=[[Science (journal)|Science]] |date=30 October 1970 |volume=170 |issue=957 |pages=518–519|doi=10.1126/science.170.3957.518 |pmid=4918766 }}</ref>

In addition to gaps in farming system technology and knowledge, some large wheat grain-producing countries have significant losses after harvest at the farm and because of poor roads, inadequate storage technologies, inefficient supply chains and farmers' inability to bring the produce into retail markets dominated by small shopkeepers. Some 10% of total wheat production is lost at farm level, another 10% is lost because of poor storage and road networks, and additional amounts are lost at the retail level.<ref>{{cite journal |title=Economic Analysis of Post-harvest Losses in Food Grains in India: A Case Study of Karnataka |author1= Basavaraja, H. |author2=Mahajanashetti, S.B. |author3=Udagatti, N.C. |journal=Agricultural Economics Research Review |volume=20 |pages=117–126 |url=http://ageconsearch.umn.edu/bitstream/47429/2/8.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://ageconsearch.umn.edu/bitstream/47429/2/8.pdf |archive-date=2022-10-09 |url-status=live|year=2007}}</ref>

In the [[Punjab region]] of the Indian subcontinent, as well as North China, irrigation has been a major contributor to increased grain output. More widely over the last 40 years, a massive increase in fertilizer use together with the increased availability of semi-dwarf varieties in developing countries, has greatly increased yields per hectare.<ref name="Godfray-2010">{{cite journal |last1=Godfray |first1=H.C. |last2=Beddington |first2=J. R. |last3=Crute |first3=I. R. |last4=Haddad |first4=L. |last5=Lawrence |first5=D. |last6=Muir |first6=J. F. |last7=Pretty |first7=J. |last8=Robinson |first8=S. |last9=Thomas |first9=S. M. |last10=Toulmin |first10=C. |display-authors=5 |year=2010 |title=Food security: The challenge of feeding 9 billion people |journal=[[Science (journal)|Science]] |volume=327 |issue=5967 |pages=812–818 |bibcode=2010Sci...327..812G |doi=10.1126/science.1185383 |pmid=20110467 |doi-access=free}}</ref> In developing countries, use of (mainly nitrogenous) fertilizer increased 25-fold in this period. However, farming systems rely on much more than fertilizer and breeding to improve productivity. A good illustration of this is Australian wheat growing in the southern winter cropping zone, where, despite low rainfall (300&nbsp;mm), wheat cropping is successful even with relatively little use of nitrogenous fertilizer. This is achieved by crop rotation with leguminous pastures. The inclusion of a [[canola]] crop in the rotations has boosted wheat yields by a further 25%.<ref>{{cite web |last=Swaminathan |first=M. S. |date=2004 |url=http://www.cropscience.org.au/icsc2004/plenary/0/2159_swaminathan.htm |archive-url=https://web.archive.org/web/20050618044418/http://cropscience.org.au/icsc2004/plenary/0/2159_swaminathan.htm |url-status=usurped |archive-date=18 June 2005 |title=Stocktake on cropping and crop science for a diverse planet |publisher=Proceedings of the 4th International Crop Science Congress, Brisbane, Australia}}</ref> In these low rainfall areas, better use of available soil-water (and better control of soil erosion) is achieved by retaining the stubble after harvesting and by minimizing tillage.<ref>{{cite web |url=http://www.grainscouncil.com/EMS/06_Nov_02_Production_Farming_Practices.pdf|title=Umbers, Alan (2006, Grains Council of Australia Limited) Grains Industry trends in Production – Results from Today's Farming Practices |url-status=dead |archive-url=https://web.archive.org/web/20170126000226/http://www.grainscouncil.com/EMS/06_Nov_02_Production_Farming_Practices.pdf |archive-date=26 January 2017}}</ref>

<gallery mode="packed" heights="150px">
File:John Constable, The Wheat Field.jpg|''[[The Wheat Field (Constable)|The Wheat Field]]'' by [[John Constable]], 1816
Wheat Farm in Behbahan, Iran.jpg|Field ready for harvesting
Unload wheat by the combine Claas Lexion 584.jpg|[[Combine harvester]] cuts the wheat stems, [[threshing|threshes]] the wheat, crushes the [[chaff]] and blows it across the field, and loads the grain onto a tractor trailer.
</gallery>