Lavaka

**Lavaka** (Maganar Malasia: [ˈlavakə]), kalmar Malagasy don "rami", yawanci ana samun ta a gefen tudu, wani nau'in fasalin rushewa ne wanda ya zama ruwan dare a Madagascar. Koyaya, an kuma sami Lavaka a Afirka ta Kudu, Jamhuriyar Demokradiyyar Kongo, da Kudancin Carolina, kuma an sami irin waɗannan siffofin ƙasa a Brazil, Great Plains na Amurka, da Eswatini. Sun fi  yankuna masu zafi tsakanin Cancer da Capricorn latitudes, musamman Tsakiyar Tsakiya ta Madagascar, inda kusan mita ɗaya mai kauri laterites ke tasowa a kan wurare masu tsawo a cikin yanayin monsoonal. Hanyar Lavaka inda waɗannan laterites masu wuya suka rufe zurfi (mita goma) Saprolite, a kan tuddai masu tsawo (digiri 35 zuwa 55), a wuraren da ke da lokacin bushe mai zafi da lokacin rigar zafi.

Lavaka ba rushewar ƙasa ba ce. Su ne wani nau'i na gully, wanda aka kafa ta hanyar ruwan kasa. Yawanci ana siffanta su kamar zubar da hawaye tare da tsayi, zagaye na kai wanda ke ƙuntata gangaren zuwa tashar tashar.

Kodayake ayyukan ɗan adam - kamar su sare daji, wuce gona da iri, ƙirƙirar hanya, da ƙone ciyawa - na iya ba da gudummawa ga samar da lava, lavakas na iya haɓaka ta hanyar hanyoyin halitta. Ayyukan Neil Wells da abokan aiki sun nuna cewa hotuna na iska sun nuna ragowar tsoffin lavakas a cikin yankunan da aka sare kwanan nan, suna nuna cewa lavakas sun lalace wa waɗancan yankuna kafin gandun daji ya girma; kuma kwanan wata na radiocarbon ya nuna cewa wasu lavakas sun kai shekaru 20,000, ma'ana suna cikin yanayin Malagasy kafin zuwan mutane (shigawar mutum a Madagascar kasa da shekaru 2000 kafin yanzu).

Daga cikin abubuwan da aka sarrafa a kan tsarin Lavaka akwai adadin Ayyukan girgizar ƙasa a yankin, taimakon ƙasa (ko gangara), da kuma yanayin ruwa na kayan a cikin Saprolite. Misali, girgizar ƙasa a yankin na iya haifar da tsagewa a cikin wuya, saman layin laterite, wanda ke ba da damar ruwa ya shiga cikin mafi yawan layin saprolite a ƙasa. Wannan yana haifar da halayen sunadarai a cikin saprolite don fitar da wasu ma'adanai daga dutsen kuma idan halayen hydraulic na wannan dutsen ya isa, ruwa na iya ɗaukar waɗannan ma'adinai, wanda zai iya haifar da kayan aikin wannan dutsen su rushe kuma su lalace.

Lavaka sau da yawa na iya haifar da lalacewa mai yawa ga al'ummomin da ke kusa. A lokacin damina, ruwan sama mai yawa yana dauke da duk kayan da suka lalace daga lava, wanda zai iya lalata amfanin gona da ababen more rayuwa da ke kewaye da shi. Wannan shine tushen yawancin binciken da aka yi kwanan nan akan masu canji da ke tattare da samar da lavaka (musamman a Madagascar, inda Lavaka ke yin albasa a yankin Highland na tsakiya).

Koyaya, lavaka ma suna da wasu fa'idodi. Sun samar da mafaka ga bishiyoyi da sauran tsire-tsire waɗanda ba za su tsira a kan gangaren ciyawa ba, kuma a lokuta da yawa manoma suna amfani da ƙasa mai kyau da wadatar ruwa a cikin lava don shuka amfanin gona.

Kalmar "Lavaka" ta shiga cikin ƙamus na ƙasa / ƙasa na ƙasa bayan aikin Riquier (1954). Don rarrabe shi daga ƙamus na rami (aka, trou, a Faransanci, da lavaka a Malagasy), wannan sabon ƙamus ya kamata a yi amfani da shi a cikin amfani da kimiyya. Mafi mahimmanci, tunda an dauki kalmar kai tsaye daga sunan gargajiya, ya kamata a dauke shi a matsayin kalma mara kyau. Don haka, Lavaka na iya zama ɗaya ko jam'i lokacin da aka yi amfani da shi.

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