El phansi kobumba Yilolo lapho ubumba lubusa phezu kwezinye izinhlayiya zabanye osayizi. Ubumba yiqembu lezinhlayiya zamaminerali ezincane kakhulu, ezingaphansi kuka-0,001 mm. Ngobubanzi, zi-odwa kusukela ezincane kuya ezinkulu ngobukhulu, ngokungafani nezinye izinhlayiya ezinkulu ezifana nodaka nesihlabathi. Inhlabathi yobumba nayo izoba nodaka nesihlabathi, kodwa ubumba luzobusa, ngezilinganiso ezihlukene kuye ngenhlabathi okukhulunywa ngayo.
Kulesi sihloko sizokutshela konke okudingeka ukwazi mayelana nomhlabathi wobumba, izici zawo, ukutshala nokunye okuningi.
Uyini umhlabathi wobumba
Inhlabathi yobumba inhlabathi okubunjwe kwayo kuhlanganisa kakhulu zibe yizinhlayiya ezingaphansi kwamamilimitha angu-0,002 ububanzi, okuthiwa ubumba. Lapho ukubusa kwenhlabathi enobumba kuphezulu kakhulu, kubhekwa njengenhlabathi enzima ngenxa yokuminyana kwayo okuphezulu.
Ngenxa yalokhu, inhlabathi enobumba imunca futhi igcine amanzi amaningi, okuholela ekutheni inhlabathi engakhanyi kahle futhi engenawo umoya kahle. Uma komile, kwakheka amagaqa, okwenza umsebenzi ube nzima, ikakhulukazi kwezolimo.
Ubumba lubaluleke kakhulu ekuvundiseni komhlabathi. Bagcina usawoti wamaminerali ngokwenza ama-aggregate nge-humus (ingxenye ye-colloidal ye-organic matter ebolile) futhi bayakwazi ukugcina amanzi. Ubumba olugqame kakhulu ama-metaclays (ubumba olukhukhumele). Lezi zinhlobo zenhlabathi zitholakala emhlabeni wonke. Phakathi kwezinhlobo ezitshalwa kakhulu phakathi kwazo irayisi ivelele. Okunye okunjengophayinaphu nerabha nakho kunomkhiqizo omuhle.
Izakhiwo zenhlabathi yobumba
Ubumba lunikeza inhlabathi ukungena kwamanzi okuphansi, umthamo omkhulu wokubamba amanzi, namandla okugcina izakhi. Lokhu kwenza amandla akho okuzala abe phezulu. Okwesibili, awangeni kahle umoya futhi asengozini ephansi kuya emaphakathi yokuguguleka.
Izakhiwo ze-physicochemical zobumba zincike ekubunjweni kwayo kwamaminerali, ikakhulukazi ohlotsheni oluyinhloko lobumba. Ngakho, isibonelo, i-allophane kunenzuzo kumthamo wokushintshaniswa kwe-cation, i-porosity, ukugcinwa komswakama kanye nesakhiwo. Nokho, i-kaolinite inomthamo wokushintshisana we-cation ophansi, izinga lokugcinwa kwezinto eziphansi, kanye nesakhiwo esivamile.
Ukuhlanganiswa
Isigaba esibalulekile senhlabathi esichazwa njengobumba ukuthungwa. Lokhu kubhekisela esilinganisweni sesihlabathi, udaka nobumba enhlabathini. Ngayinye yalezi zinto iyisigaba se-granular. Uma izinhlayiya zobumba zimele ama-25% kuya ku-45% wesamba sezinhlayiya ezisemhlabathini, kungabhekwa njengobumba olunesihlabathi, ubumba olumahhadla noma ubumba olunodaka. Uma ubumba lungaphezu kuka-45% wengqikithi yokwakheka, sinobumba obuhle.
I-Porosity, i-permeability kanye nokuphefumula
Ngokwezinga ubumba olunquma ngayo ukuthungwa nokwakheka kwenhlabathi, liphinde libe nomthelela ekuqineni kwalo. Ngenxa yobukhulu bazo obuncane, izinhlayiya zobumba zishiya izimbotshana ezincane kakhulu. Lokhu kuvimbela ukuhamba kwamanzi nomoya ku-matrix yenhlabathi. Lezi zimo zidala ukugcwala komhlabathi, okubangela ukuthi amanzi angaphezulu amile ngoba akwenzeki ukungena.
Uma izimbotshana zenhlabathi zigcwele amanzi, i-rhizosphere ibulawa yindlala yomoya-mpilo (ukuntuleka kwe-oxygen). Ngaphansi kwalezi zimo, izitshalo eziningi ezitshalwayo zinenkinga yokukhula.
Lapho kukhona i-humus, ubumba lubonisa uhlangothi oluhle. Ama-clay-humus complexes akhiwa futhi ama-aggregate makhulu. Ngenxa yalokho, ama-pores nawo akhulu, athuthukisa ukungena nokuphefumula.
Umthamo wokushintshaniswa kwe-cation
Uma ubumba nezinto eziphilayo zingagcini ama-cations, azokhukhulwa ngamanzi aqonde endaweni ephansi (leaching), okulimaza ukuvunda komhlabathi. Umthamo wokushintshaniswa kwe-cation kungenxa yokuthi kokubili i-humus nobumba enhlabathini kunenkokhelo engalungile.
I-pH yomhlabathi ithinta amandla okushintshaniswa kwe-cation. Kuya ohlotsheni lobumba emhlabathini. Uma i-kaolin ne-allophane zikhona, ukushajwa okunegethivu kushintsha ne-pH. Ngenkathi isilinganiso sobumba olunwetshiwe singu-2:1, ukukhokhiswa akushintshi kunoma iyiphi i-pH.
Imiphumela ku-microbiota yenhlabathi enobumba
Ama-microorganisms omhlaba asungule ubudlelwano bokunamathela kanye nokuhlukanisa nezinhlayiya zobumba. Kule ndawo, izinqubo zokushintshanisa i-ion zenzeka ezibanjwa noma ezikhishwe ama-microorganisms.
Ngenxa yokungafinyeleli kwayo okuncane, ubumba lulungele amachibi amanzi emvelo noma okwenziwa. Amanye ama-aquifer akhiwa ngenxa yokuba khona kwezingqimba zobumba ekujuleni okuthile.
Iningi lobumba liyingxenye yeqembu lama-phyllosilicates (ama-silicates agqinsiwe). Kunezinhlobo ezahlukene kuye ngenani lephepha elakha isakhiwo salo. Okuchichima kakhulu yi-muscovite, i-kaolinite, i-biotite, i-chlorite, i-vermiculite, ne-montmorillonite. Omunye umndeni wobumba ochichima ngokulingene ama-quartz oxides. Ezimweni ezingavamile kakhulu sithola i-feldspar, i-hematite, i-goethite, i-calcite, i-gypsum ne-halite. I-Cristobalite kanye ne-amorphous material itholakala ebumbeni lwemvelaphi ye-pyroclastic (umlotha we-volcanic).
Ngenxa yemvelo ye-colloidal yezinhlayiya zayo, ubumba lugcina inani elikhulu lamaminerali. Ubumba luvame ukugcina insimbi (Fe) kanye nezinga elincane le-aluminium (Al). Njengoba ubumba lugcina amanzi amaningi, kwenzeka inqubo ye-oxidation. Ama-iron oxide ane-hydrated enza lenhlabathi ibe nombala ophuzi noma obomvu.
Ukwakheka kwenhlabathi yobumba
Ubumba luhlangana nezinto eziphilayo futhi lunomthelela ekuzinzeni kwesakhiwo senhlabathi. Ezimweni eziningi, yi-clay-humus complex ekhuthaza ukwakheka kwe-aggregates yenhlabathi. Ngakolunye uhlangothi, i-sodium iphazamisa ubumba.
Uma i-substrate ingubumba ngokuphelele, ayinakho isakhiwo futhi ayivumeli amanzi ukuba angene. Lokhu ekugcineni kuholela ekucineni nasekuqineni. Ezimweni zezulu ezishisayo zonyaka, inhlabathi equkethe ubumba oluvuvukalayo iba nezinguquko eziphawulekayo zesakhiwo kuye ngezimo zomswakama.
Ngenkathi yezimvula, ubumba luyakhukhumala futhi umhlabathi ugcwala kalula, uthambile, unamathele futhi uthambile. Phakathi nenkathi eyomile, ubumba luyashwabana, luveze inhlabathi eqinile, eqhekekile.
Izitshalo ezivela kule nhlabathi
Izici ezibalulekile okufanele zicatshangelwe lapho usebenza nenhlabathi enobumba kwezolimo ukugeleza kwamanzi kanye ne-asidi. Isivuno esihle kakhulu senhlabathi yobumba ilayisi. Ukotini, umoba, namabele kungatshalwa uma uphathwa ngendlela efanele.
Ezinye izitshalo ezikwazi ukumelana ne-asidi nezingadingi mthetho, njengophayinaphu, irabha, noma isundu lase-Afrika, zingatshalwa ezinhlotsheni ezithile zenhlabathi yobumba. Phakathi kwezitshalo ezihlala njalo, ezinye izihlahla zezithelo zijwayela inhlabathi enobumba. Phakathi kwezihlahla zezithelo zesimo sezulu esipholile kukhona i-apula, i-pear, i-quince, i-hazelnut ne-walnut. Amahlathi atshaliwe nawo angenzeka.
Ngithemba ukuthi ngalolu lwazi ungafunda kabanzi mayelana nokuthi iyini inhlabathi enobumba kanye nezici zayo.