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== Утицај на биљке ==
===Damage Оштећење ===
[[FileДатотека:Feuilles-avec-glace-leaves-with-ice-1.jpg|лево|250px|thumb|FrostМраз onна theтрави grassјавног ofпарка aу public park in Novemberновембру]]
[[FileДатотека:Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 31) (cropped).jpg|thumb|right|250px|MapМапа ofпросечног averageпрвог firstсмртоносног killingмраза frostу inОхају Ohioиз from„Географије "Geography of OhioОхаја“," 1923]]
Many plants can be damaged or killed by freezing temperatures or frost. This varies with the type of plant, the tissue exposed, and how low temperatures get; a "light frost" of {{convert|-2|to|0|C|F}} damages fewer types of plants than a "hard frost" below {{convert|-2|C|F}}.<ref name="BI_Frost">{{cite web |url=http://www.botanicalinterests.com/articles/view/26/Frost-Tolerance-of-Vegetables |title=Frost Tolerance of Vegetables |publisher=Botanical Interests |access-date=Nov 12, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131113010216/http://www.botanicalinterests.com/articles/view/26/Frost-Tolerance-of-Vegetables |archive-date=2013-11-13 }}</ref>
PlantsМноге likelyбиљке toмогу beбити damagedоштећене evenили byубијене aниским lightтемпературама frostили includeмразом. vines—suchОво asварира beans,у grapes,зависности squashes,од melons—alongврсте withбиљке, [[nightshade]]sизложеног suchткива asи tomatoes,ниских eggplants,температура; and„лаки peppers.мраз“ Plantsод that{{convert|-2|to|0|C|F}} mayоштећује tolerateмање (orврста evenбиљака benefitод from)„јаког frostsмраза“ include:испод {{convert|-2|C|F}}.<ref name="BI_Frost">{{cite web |url=http://www.grow-it-organicallybotanicalinterests.com/fallarticles/view/26/Frost-vegetables.htmlTolerance-of-Vegetables |title=FallFrost vegetablesTolerance vs.of SummerVegetables |publisher=Botanical Interests |access-date=Nov 12, vegetables2013 |url-status=livedead |archive-url=https://web.archive.org/web/2013111301115920131113010216/http://www.grow-it-organicallybotanicalinterests.com/fallarticles/view/26/Frost-vegetables.htmlTolerance-of-Vegetables |archive-date=2013-11-13 }}</ref>
*root vegetables (e.g. beets, carrots, parsnips, onions)
*leafy greens (e.g. lettuces, spinach, chard, cucumber<ref name="JHR_2-2013">{{Citation|url=http://www.degruyter.com/view/j/johr.2013.21.issue-2/johr-2013-0031/johr-2013-0031.xml?format=INT|last=Klosinska|first=Urszula|date=27 February 2014|publisher=de Gruyter|access-date=2014-02-28|title=Low temperature seed germination of cucumber: genetic basis of the tolerance trait|journal=Journal of Horticultural Research|volume=21|issue=2|pages=125–130|display-authors=etal|url-status=live|archive-url=https://web.archive.org/web/20140611011158/http://www.degruyter.com/view/j/johr.2013.21.issue-2/johr-2013-0031/johr-2013-0031.xml?format=INT|archive-date=11 June 2014|doi=10.2478/johr-2013-0031|doi-access=free}}</ref>) ▼*[[cruciferous vegetables]] (e.g. cabbages, cauliflower, bok choy, broccoli, Brussels sprouts, radishes, kale, collard, mustard, turnips, rutabagas)
Биљке које ће вероватно оштетити чак и слаб мраз укључују [[Врежа|вреже]] — као што су пасуљ, грожђе, тикве, диње — заједно са [[nightshade|велебиљима]] као што су парадајз, патлиџан и паприка. Биљке које могу толерисати (или чак имати користи од) мразева укључују:<ref>{{cite web |url=http://www.grow-it-organically.com/fall-vegetables.html |title=Fall vegetables vs. Summer vegetables |url-status=live |archive-url=https://web.archive.org/web/20131113011159/http://www.grow-it-organically.com/fall-vegetables.html |archive-date=2013-11-13 }}</ref>
Certain [[bacterium|bacteria]], notably ''[[Pseudomonas syringae]]'', are particularly effective at triggering frost formation, raising the nucleation temperature to about {{convert|-2|C|F}}.<ref>{{cite journal |vauthors=Maki LR, Galyan EL, Chang-Chien MM, Caldwell DR |title=Ice Nucleation Induced by Pseudomonas syringae |journal=Applied Microbiology |volume=28 |issue=3 |year=1974 |pages=456–459 |pmid=4371331 |pmc=186742 |doi=10.1128/aem.28.3.456-459.1974}}</ref> Bacteria lacking ice [[nucleation]]-active proteins ([[ice-minus bacteria]]) result in greatly reduced frost damage.<ref>{{cite journal ▼* коренасто поврће (нпр. цвекла, шаргарепа, пастрњак, лук)
▲* leafy greensлиснато поврће ( e.gнпр. lettucesзелена салата, spinachспанаћ, chardблитва, cucumberкраставац<ref name="JHR_2-2013">{{Citation|url=http://www.degruyter.com/view/j/johr.2013.21.issue-2/johr-2013-0031/johr-2013-0031.xml?format=INT|last=Klosinska|first=Urszula|date=27 February 2014|publisher=de Gruyter|access-date=2014-02-28|title=Low temperature seed germination of cucumber: genetic basis of the tolerance trait|journal=Journal of Horticultural Research|volume=21|issue=2|pages=125–130|display-authors=etal|url-status=live|archive-url=https://web.archive.org/web/20140611011158/http://www.degruyter.com/view/j/johr.2013.21.issue-2/johr-2013-0031/johr-2013-0031.xml?format=INT|archive-date=11 June 2014|doi=10.2478/johr-2013-0031|doi-access=free}}</ref>)
* [[cruciferous vegetables|крсташице]] (нпр. купус, карфиол, бок чој, броколи, [[прокељ]], ротквице, кељ, [[раштан]], сенф, репа, подземна кораба)
▲CertainОдређене [[bacterium| bacteriaбактерије]], notablyпосебно ''[[Pseudomonas syringae]]'', areсу particularlyпосебно effectiveефикасне atу triggeringпокретању frostстварања formationмраза, raisingподижући theтемпературу nucleation temperatureнуклеације toна aboutоко {{convert|-2|C|F}}.<ref>{{cite journal |vauthors=Maki LR, Galyan EL, Chang-Chien MM, Caldwell DR |title=Ice Nucleation Induced by Pseudomonas syringae |journal=Applied Microbiology |volume=28 |issue=3 |year=1974 |pages=456–459 |pmid=4371331 |pmc=186742 |doi=10.1128/aem.28.3.456-459.1974}}</ref> BacteriaБактерије lackingкојима iceнедостају протеини активни у [[nucleation |нуклеацији]] -active proteinsледа ([[ice-minus bacteria |лед-минус бактерије]]) resultдоводе до inзнатно greatlyсмањеног reducedоштећења frostод damageмраза.<ref>{{cite journal
|last= Lindow |first= Stephen E. |author-link= Steven E. Lindow |author2=Deane C. Arny |author3=Christen D. Upper |title= Bacterial Ice Nucleation: A Factor in Frost Injury to Plants
|journal= Plant Physiology
|pmc= 1065830}}</ref>
=== Методе заштите ===
===Protection methods===
[[FileДатотека:Winterschutz.jpg|thumb|лево|250px|[[Roses|Руже]] withса protectionзаштитом againstод frostмраза - [[Volksgarten, Vienna|Фолксгартен]], Беч ]]
[[FileДатотека:CuritibaFrostGeada.jpg|thumb|right|250px|[[Curitiba|Куритиба]] ([[Southern Brazil|Јужни Бразил]]) isје the coldest ofнајхладнији [[Brazilstate capital|главни град]]'s [[state capitalBrazil|бразилске]]s државе; the [[greenhouse|стакленик]] of the [[Botanical Garden of Curitiba|Ботаничке баште Куритиба]] protectsштити sensitiveосетљиве plantsбиљке.]]
Typical measures to prevent frost or reduce its severity include one or more of:
Типичне мере за спречавање мраза или смањење његове озбиљности укључују једну или више од:
*deploying powerful blowers to simulate wind, thereby preventing the formation of accumulations of cold air. There are variations on this theme. One variety is the wind machine, an engine-driven propeller mounted on a vertical pole that blows air almost horizontally. Wind machines were introduced as a method for frost protection in California during the 1920s, but they were not widely accepted until the 1940s and 1950s. Now, they are commonly used in many parts of the world.<ref>wind machine references: http://www.fao.org/3/y7223e/y7223e0d.htm ; https://extension.psu.edu/orchard-frost-protection-with-wind-machines ; http://www.omafra.gov.on.ca/english/engineer/facts/10-045.htm ;</ref> Another is the [[selective inverted sink]],<ref>[http://www.rolexawards.com/laureates/laureate-20-guarga.html Selective Inverted Sink] {{webarchive|url=https://web.archive.org/web/20060318212517/http://www.rolexawards.com/laureates/laureate-20-guarga.html |date=2006-03-18}} Rolex Awards site (won award in ''Technology and Innovation'' category) 1998.</ref> a device which prevents frost by drawing cold air from the ground and blowing it up through a chimney. It was originally developed to prevent frost damage to [[citrus]] fruits in [[Uruguay]]. In New Zealand, [[helicopter]]s are used in similar fashion, especially in the [[vineyard]] regions such as [[Marlborough Region|Marlborough]]. By dragging down warmer air from the [[Inversion (meteorology)|inversion layers]], and preventing the ponding of colder air on the ground, the low-flying helicopters prevent damage to the fruit buds. As the operations are conducted at night, and have in the past involved up to 130 aircraft per night in one region, safety rules are strict.<ref>''Helicopters Fight Frost'' – ''Vector'', [[Civil Aviation Authority of New Zealand]], September/ October 2008, Page 8-9</ref> Although not a dedicated method, [[wind turbine]]s have similar (small) effect of vertically mixing air layers of different temperature.<ref name="Nature-2010.12.23">[http://www.nature.com/nature/journal/v468/n7327/full/4681001a.html Turbines and turbulence] {{webarchive|url=https://web.archive.org/web/20111201212633/http://www.nature.com/nature/journal/v468/n7327/full/4681001a.html |date=2011-12-01}}, ''[[Nature (journal)]]'', 468, 1001, 23 December 2010, DOI:10.1038/4681001a, published online 22 December 2010.</ref><ref name="Roy+Traiteur">Somnath Baidya Roy and Justin J. Traiteur. [http://www.pnas.org/content/early/2010/10/12/1000493107.abstract Impacts of wind farms on surface air temperatures], Proceedings of the National Academy of Sciences, Vol. 107, No. 42, October 19, 2010, p. 17,899.</ref><ref name="ScienceDaily-2005">[https://www.sciencedaily.com/videos/2005/1012-wind_farms_impacting_weather.htm Wind farms impacting weather] {{webarchive|url=https://web.archive.org/web/20100906101845/https://www.sciencedaily.com/videos/2005/1012-wind_farms_impacting_weather.htm |date=2010-09-06}}, Science Daily.</ref> ▼
*For high-value crops, farmers may [[tree wrap|wrap trees]] and cover crops.
▲* deploying powerfulПостављање blowersснажних toдуваљки simulateда windсимулирају ветар, therebyчиме preventingсе theспречава formationстварање ofнакупина accumulationsхладног of cold airваздуха. ThereПостоје areваријације variations onна thisову themeтему. OneЈедна varietyврста isје theмашина windза machineветар, anпропелер engine-drivenса propellerмотором mountedпостављен onна aвертикални verticalстуб poleкоји thatдува blowsваздух airскоро almost horizontallyхоризонтално. WindВетромашине machinesсу wereуведене introducedкао asметода aзаштите methodод forмраза frostу protectionКалифорнији inтоком California during the 1920s1920-их, butали theyнису wereбиле notшироко widelyприхваћене acceptedсве untilдо the1940-их 1940sи and 1950s1950-их. Now,Сада theyсе areобично commonlyкористе usedу in many parts ofмногим theделовима worldсвета.<ref>wind machine references: http://www.fao.org/3/y7223e/y7223e0d.htm ; https://extension.psu.edu/orchard-frost-protection-with-wind-machines ; http://www.omafra.gov.on.ca/english/engineer/facts/10-045.htm ;</ref> AnotherДруги is theје [[selective inverted sink |селективни обрнути сливник]],<ref>[http://www.rolexawards.com/laureates/laureate-20-guarga.html Selective Inverted Sink] {{webarchive|url=https://web.archive.org/web/20060318212517/http://www.rolexawards.com/laureates/laureate-20-guarga.html |date=2006-03-18}} Rolex Awards site (won award in ''Technology and Innovation'' category) 1998.</ref> aуређај deviceкоји whichспречава preventsмраз frostтако byшто drawingизвлачи coldхладан airваздух fromиз theземље groundи andиздува blowingга itкроз up through a chimneyдимњак. ItПрвобитно wasје originallyразвијен developed to prevent frostда damageспречи toоштећење [[ citrusцитрус]] а fruitsод inмраза у [[ UruguayУругвај]] у. InНа NewНовом Zealand,Зеланду [[helicopter |хеликоптери]] s areсе usedкористе inна similarсличан fashionначин, especiallyпосебно in theу [[ vineyardвиноград]] арским regionsрегионима suchкао asшто је [[Marlborough Region| MarlboroughМарлборо]]. By dragging down warmerПовлачећи airтоплији fromваздух theиз [[Inversion (meteorology)| inversionинверзивних layersслојева]] , andи preventingспречавајући theнакупљање pondingхладнијег of colder air onваздуха theна groundтлу, theнисколетећи low-flyingхеликоптери helicoptersспречавају preventоштећење damageплодних to the fruit budsпупољака. AsПошто theсе operationsоперације areизводе conducted at nightноћу, andа haveу inпрошлости theсу pastукључивале involvedи up toдо 130 aircraftлетилица perпо nightноћи inу oneједном regionрегиону, safetyбезбедносна rulesправила areсу strictстрога.<ref>''Helicopters Fight Frost'' – ''Vector'', [[Civil Aviation Authority of New Zealand]], September/ October 2008, Page 8-9</ref> AlthoughИако notније aнаменска dedicated methodметода, [[wind turbine |ветротурбине]] s haveимају similarсличан ( smallмали) effectефекат ofвертикалног verticallyмешања mixingслојева air layers ofваздуха differentразличите temperatureтемпературе.<ref name="Nature-2010.12.23">[http://www.nature.com/nature/journal/v468/n7327/full/4681001a.html Turbines and turbulence] {{webarchive|url=https://web.archive.org/web/20111201212633/http://www.nature.com/nature/journal/v468/n7327/full/4681001a.html |date=2011-12-01}}, ''[[Nature (journal)]]'', 468, 1001, 23 December 2010, DOI:10.1038/4681001a, published online 22 December 2010.</ref><ref name="Roy+Traiteur">Somnath Baidya Roy and Justin J. Traiteur. [http://www.pnas.org/content/early/2010/10/12/1000493107.abstract Impacts of wind farms on surface air temperatures], Proceedings of the National Academy of Sciences, Vol. 107, No. 42, October 19, 2010, p. 17,899.</ref><ref name="ScienceDaily-2005">[https://www.sciencedaily.com/videos/2005/1012-wind_farms_impacting_weather.htm Wind farms impacting weather] {{webarchive|url=https://web.archive.org/web/20100906101845/https://www.sciencedaily.com/videos/2005/1012-wind_farms_impacting_weather.htm |date=2010-09-06}}, Science Daily.</ref>
*Heating to slow the drop in temperature is not practical except for high-value crops grown over small areas.
* За усеве високе вредности, фармери могу [[tree wrap|умотати]] дрвеће и покрити усеве.
*Production of smoke to reduce cooling by radiation
* Загревање за успоравање пада температуре није практично осим за усеве високе вредности који се узгајају на малим површинама.
*Spraying crops with a layer of water releases latent heat, preventing harmful freezing of the tissues of the plants that it coats.
* Производња дима за смањење хлађења зрачењем
Such measures need to be applied with discretion, because they may do more harm than good; for example, spraying crops with water can cause damage if the plants become overburdened with ice. An effective, '''low cost''' method for small crop farms and plant nurseries, exploits the [[enthalpy of fusion|latent heat of freezing]]. A pulsed irrigation timer<ref name=Nurseries/> delivers water through existing overhead sprinklers at a low volumes to combat frosts down to {{convert|-5|C|F}}.<ref name=Nurseries>{{cite web|title=A practical method of frost protection|url=http://plantsale.com.au/Articles/FrostProtection|access-date=31 October 2011|url-status=live|archive-url=https://web.archive.org/web/20120320075831/http://www.plantsale.com.au/Articles/FrostProtection/|archive-date=20 March 2012}}</ref><ref name=SmallCrops>{{cite web|last=Selders|first=Arthur W.|title=Frost protection with sprinkler irrigation|url=http://www.wvu.edu/~agexten/hortcult/fruits/om101.pdf|publisher=West Virginia university|access-date=31 October 2011|url-status=dead|archive-url=https://web.archive.org/web/20111114032130/http://www.wvu.edu/~agexten/hortcult/fruits/om101.pdf|archive-date=14 November 2011}}</ref> If the water freezes, it gives off its latent heat, preventing the temperature of the foliage from falling much below zero.<ref name=SmallCrops/> ▼* Прскање усева слојем воде ослобађа латентну топлоту, спречавајући штетно смрзавање ткива биљака које облаже.
▲SuchТакве measuresмере needтреба toпримењивати be applied with discretionдискреционо, becauseјер theyмогу mayдонети doвише moreштете harmнего than goodкористи; forна exampleпример, sprayingпрскање cropsусева withводом waterможе canпроузроковати causeштету damageако ifсе theбиљке plantsпреоптерете become overburdened with iceледом. An effectiveЕфикасан, '''lowјефтин cost'''метод methodза forмале smallфарме cropусева farmsи andрасаднике plant nurseriesбиљака, exploits theкористи [[enthalpy of fusion| latentлатентну heatтоплоту of freezingсмрзавања]]. AИмпулсни pulsedтајмер irrigationза timerнаводњавање<ref name=Nurseries/> delivers waterиспоручује throughводу existingкроз overheadпостојеће sprinklersгорње atпрскалице aу lowмалим volumesколичинама toза combatборбу frostsпротив downмраза toдо {{convert|-5|C|F}}.<ref name=Nurseries>{{cite web|title=A practical method of frost protection|url=http://plantsale.com.au/Articles/FrostProtection|access-date=31 October 2011|url-status=live|archive-url=https://web.archive.org/web/20120320075831/http://www.plantsale.com.au/Articles/FrostProtection/|archive-date=20 March 2012}}</ref><ref name=SmallCrops>{{cite web|last=Selders|first=Arthur W.|title=Frost protection with sprinkler irrigation|url=http://www.wvu.edu/~agexten/hortcult/fruits/om101.pdf|publisher=West Virginia university|access-date=31 October 2011|url-status=dead|archive-url=https://web.archive.org/web/20111114032130/http://www.wvu.edu/~agexten/hortcult/fruits/om101.pdf|archive-date=14 November 2011}}</ref> IfАко theсе waterвода freezesзамрзне, itодаје givesсвоју offлатентну its latent heatтоплоту, preventing the temperature ofспречавајући theда foliageтемпература fromлишћа fallingпадне muchмного belowиспод zeroнуле.<ref name=SmallCrops/>
== Занимљивост ==
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