Yankin da ya fi wuya

Yankin juriya yanki ne na ƙasa wanda aka bayyana kamar yana da matsakaicin matsakaicin zafin jiki na shekara-shekara, wani abu da ya dace da rayuwar shuke-shuke da yawa. A wasu tsarin an haɗa wasu kididdigar a cikin lissafin. Tsarin asali kuma mafi yawan amfani da shi, wanda Ma'aikatar Aikin Gona ta Amurka (USDA) ta haɓaka a matsayin jagora mai zurfi don shimfidar wuri da lambu, ya bayyana yankuna 13 ta hanyar matsakaicin matsakaicin yanayin zafi na shekara-shekara. An daidaita shi da wasu ƙasashe (kamar Kanada) a cikin nau'o'i daban-daban. Ana iya bayyana shuka a matsayin "mai tsayayya da yanki 10": wannan yana nufin cewa shuka na iya tsayayya le mafi ƙarancin zafin jiki na -1.1 zuwa 4.4 ° C (30 zuwa 40 ° F).

Sai dai idan an ƙayyade in ba haka ba, a cikin yanayin Amurka "yanki mai wuya" ko kuma kawai "yanki" yawanci yana nufin sikelin USDA. Koyaya, wasu rikice-rikice na iya kasancewa a tattauna gine-gine da HVAC, inda "yanki na yanayi" na iya komawa zuwa yankunan Dokar Kula da Makamashi ta Duniya, inda Yankin 1 yake da dumi kuma Yankin 8 yana da sanyi.

An kuma haɓaka wasu tsare-tsaren ƙididdigar ƙarfi, kamar su Royal Horticultural Society na Burtaniya da tsarin littafin Sunset Western Garden Book na Amurka. **Yankin zafi** (duba ƙasa) a maimakon haka an bayyana shi ta yanayin zafi na shekara-shekara; Yankin zafi na American Horticultural Society (AHS) suna amfani da matsakaicin adadin kwanaki a kowace shekara lokacin da zafin ya wuce  ° C (86 ° F).

## Yankunan juriya na Amurka (scale na USDA)

An kirkiro tsarin USDA ne don taimakawa masu lambu da masu shimfidar wuri a Amurka.

A cikin Amurka, yawancin yankuna masu zafi (zones 9, 10, da 11) suna cikin zurfin kudancin ƙasar, a gefen kudancin, da kuma bakin tekun Pacific. Ana iya samun yankuna masu tsawo a Hawaii (har zuwa 12) da Puerto Rico (har zuwa 13). Yankin tsakiya na kudancin yankin da ke tsakiyar bakin teku suna cikin yankuna na tsakiya (zones 8, 7, da 6). Yankin arewacin da ke tsakiyar tsakiyar yankin yana da wasu yankuna mafi sanyi (zones 5, 4, da karamin yanki na yanki 3) kuma sau da yawa suna da yanayin zafi a cikin hunturu saboda kasancewa mafi yawan nahiya, musamman a yamma tare da bambancin zafin rana, kuma ta haka ne taswirar yankin tana da iyakokinta a waɗannan yankuna. Ana iya samun ƙananan yankuna a Alaska (har zuwa 1). Rashin latitude kuma sau da yawa yanayin da ya dace a Florida, Gulf Coast, da kudancin Arizona da California, suna da alhakin ƙarancin abubuwan da suka faru na sanyi mai tsanani dangane da na al'ada a waɗancan yankuna. Yankin da ya fi zafi a cikin jihohi 48 da ke kusa da shi shine Florida Keys (11b) kuma mafi sanyi yana cikin arewa maso tsakiyar Minnesota (2b). Wasu wurare a arewacin gabar tekun Puerto Rico suna da yankin da ya fi zafi a Amurka a 13b. Sabanin haka, yankunan da ke kewaye da Alaska suna da yankin sanyi mafi sanyi a Amurka a 1a.

### Ma'anar

### Tarihi
Masu bincike biyu ne suka yi ƙoƙari na farko don ƙirƙirar tsarin yanki na tsauraran ƙasa a Arnold Arboretum a Boston; na farko an buga shi a 1927 ta hanyar Alfred Rehder,  kuma na biyu ta hanyar Donald Wyman a 1938.  An sabunta taswirar Arnold a 1951, 1967, kuma a ƙarshe 1971, amma daga ƙarshe ya ɓace gaba ɗaya.

Tsarin USDA na zamani ya fara ne a US National Arboretum a Washington. An bayar da taswirar farko a cikin 1960, kuma an sake shi a cikin 1965. Ya yi amfani da uniform  ° F (5.6 ° C) kewayon, kuma a hankali ya zama yadu tsakanin masu lambu na Amurka.

An sake fasalin taswirar USDA kuma an sake buga shi a cikin 1990 tare da sabbin bayanan yanayi, a wannan lokacin tare da bambance-bambance na digiri biyar da ke raba kowane yanki zuwa sabbin sassan "a" da "b".

A shekara ta 2003, American Horticultural Society (AHS) ta samar da taswirar da aka sake sabuntawa, ta amfani da bayanan zafin jiki da aka tattara daga Yuli 1986 zuwa Maris 2002. Taswirar 2003 ta sanya yankuna da yawa kusan rabin yanki mafi girma (mai dumi) fiye da taswirar USDA ta 1990. Masu bita sun lura da yankunan taswirar sun kasance kusa da taswirar USDA ta asali ta 1960 a cikin cikakkun yankuna. Taswirarsu an yi niyyar nuna cikakkun bayanai, alal misali, nuna tsibirai masu zafi na birane ta hanyar nuna yankunan da ke cikin birane da yawa (misali, Baltimore, Maryland; Washington, DC, da Atlantic City, New Jersey) a matsayin cikakken yanki mai dumi fiye da yankunan da ba su da kyau. Taswirar ta cire cikakkun bayanai game da rabin yankuna da aka gabatar a cikin taswirar USDA ta 1990, wani watsi da shi da aka soki ta hanyar masu horticulturists da masu lambu saboda rashin tausayi na taswirar da ta biyo baya. USDA ta ki amincewa da taswirar AHS 2003 kuma ta kirkiro taswirar kanta a cikin tsarin kwamfuta mai ma'amala, wanda American Horticultural Society ke amfani da shi yanzu.

## Manazarta