Uma izimpande zesistimu yakho ye-hydroponics yaseklasini zinuka njengamanzi exhaphozi, zishelela eminweni yakho, futhi zisuke ekubeni mhlophe kokuphaphathekile zaba nsundu ngokufiphele, izitshalo zakho zinokubola kwezimpande (root rot). Cishe kuzo zonke izilungiselelo zezikole, imbangela enkulu yi-Pythium—iqembu lesikhunta samanzi esithatha amathuba esingena ezimpandeni ezicindezelekile lapho amanzi ethangini eshisa kakhulu futhi ephelelwa umoyampilo oncibilikile (dissolved oxygen).

Lokhu akukhona ukwehluleka kwabafundi bakho ekuxubeni izakhi zomsoco noma isifo sezitshalo esingachazeki. Kuyinkinga ebonakalayo yefiziksi nebhayoloji evamile ezikoleni zaseNingizimu Afrika phakathi kuka-Okthoba noMashi: amakilasi avaliwe abamba ukushisa ngezimpelasonto, amazinga okushisa ethangini akhuphuka adlule ku-24°C, amazinga omoyampilo oncibilikile awe phansi, kanti izinhlamvu zesikhunta ezilele ziyaphaphama zidle amalangabi. Nakhu okwenzeka ngamakhemikhali emvelweni (biochemically), indlela yokuhlenga isivuno sakho samanje, nendlela yokukuvimbela ukuba kungenzeki futhi ngesabelomali sesikole esincane.

Ifiziksi Eyisisekelo: Amanzi Afudumele Awakwazi Ukubamba Umoya

Izitshalo zimunca amanzi nezakhi zomsoco ngezimpande zazo zisebenzisa i-active transport, inqubo edla amandla amaningi edinga umoyampilo. Emhlabathini onempilo, izikhala zomoya zinikeza lokhu kukhishwa nokungeniswa kwegesi. Ethangini le-hydroponics (kungaba ibhokisi le-Deep Water Culture noma umsele we-Nutrient Film Technique), izimpande kumele zidonse umoyampilo oncibilike ngqo emanzini.

Umkhawulo wemvelo lapha ulula: amanzi abandayo abamba igesi encibilikile eningi kakhulu kunamanzi afudumele. Ku-18°C kuya ku-20°C—izinga elifanele lezitshalo ezinamaqabunga eziluhlaza njengolethisi nesipinashi—amanzi abamba kalula cishe amamiligremu ayi-9 kuya kwayi-10 omoyampilo oncibilikile ilitha ngalinye. Lapho ikilasi laseNingizimu Afrika elingenaso isipholisa-moya livalwa ngo-14:00 ngoLwesihlanu kanti izinga lokushisa langaphakathi lifinyelela ku-32°C ngempelasonto, amanzi ethangini ajwayele ukukhuphuka adlule ku-26°C. Kulelo zinga lokushisa, ukugcwala kwehla kube ngaphansi kuka-8 mg/L, kanti isidingo somoyampilo sokugaya ukudla sakho kokubili izimpande namagciwane anenzuzo adinga umoya cishe siphindaphindeka kabili.

Izimpande ziqala ukuphelelwa umoya. Izicubu zazo zangaphandle ziyafa bese ziyaxebuka, zikhiqize ungqimba lwemvelo olunamathelayo. Ama-zoospores e-Pythium, atholakala yonke indawo othulini, emanzini ompompi, nasezintweni ezingahlanzwanga ngemithi, abona lokhu kubola okukhishwa izimpande, abhukude aqonde kukho, bese engena ngamandla ezicubini ezifayo. Isilayimi esinsundu osibonayo yizicubu zangaphandle zezimpande ezifile ezixubene nemicu yesikhunta (fungal mycelium).

Uhlelo Lwesimo Esiphuthumayo: Ukuhlenga Ngezinyathelo Ezintathu

Uma izitshalo zakho zibuna yize ithangi ligcwele amanzi, thatha isinyathelo ngokushesha. Uma ngaphezu kuka-70% wesisindo sezimpande sesivele sinjengodaka olucubuzekile, zilahle izitshalo, chitha amanzi ethangini, bese uqala phansi. Uma umgogodla wempande usesimweni esihle, uvamise ukukwazi ukusindisa isivuno usebenzisa i-hydrogen peroxide ejwayelekile engu-3% (H₂O₂), etholakala kunoma iyiphi ikhemisi yendawo noma isuphamakethe ngemali elinganiselwa ku-R15 kuya ku-R30 ibhodlela.

1. Ukuthena ngezandla nokugeza izimpande

Khipha izimbiza ezingamanetha (net pots) ngokucophelela ohlelweni. Ngaphansi kompompi oveza amanzi abandayo agobhozayo, phulula kahle izimpande ubheke phansi ukuze ugeze ungqimba oluxekethile olunamathelayo. Ungasabi ukukhipha igobolondo elinsundu elixebukile; ingxenye yangaphakathi emhlophe enemicu yiyo okudingeka uyilondoloze. Usebenzisa isikelo esihlanzekile esibulale amagciwane nge-methylated spirits, nquma izihloko zezimpande ezimnyama nezibolile.

2. Ukugeza ngokubulala amagciwane nge-hydrogen peroxide

Xuba amanzi okugeza esimo esiphuthumayo ebhakedeni elihlanzekile: sebenzisa u-5 ml kuya ku-10 ml we-hydrogen peroxide ejwayelekile engu-3% ilitha ngalinye lamanzi ompompi ahlanzekile nabandayo. Gwilisa izimpande ezithenisiwe kule ngxube imizuzu eyi-15 kuya kwengama-20. I-peroxide izokwenza i-oxidise kuzinhlamvu ze-Pythium ezisele kanye nezicubu ezifile, ivamise ukukhipha amagwebu kancane njengoba ikhipha ama-free oxygen radical. Ngeke ilimaze izicubu zezimpande ezinempilo ezisaphila kulesi silinganiso esixutshiwe.

3. Ukuhlanza nokulungisa ithangi kabusha

Ngenkathi izimpande zicwile, khulula ithangi lakho ngokuphelele. Khuhla ithangi, iphampu ecwiliswayo (submersible pump), namapayipi okuhambisa amanzi ngengxube engu-10% ye-bleach yasendlini noma amanzi afudumele anensipho, hlambulula kahle kuze kuphele iphunga le-chlorine, bese ugcwalisa ngamanzi ahlanzekile. Faka ifomula yakho evamile yezakhi zomsoco ngesigamu samandla ayo emahoreni angama-48 okuqala ukuze ugweme ukwethusa uhlelo lwezimpande olulimele, bese ufaka u-2 ml kuya ku-3 ml we-hydrogen peroxide engu-3% ilitha ngalinye lomthamo wethangi ukuze kubulawe izinhlamvu ezisele kumapayipi. I-peroxide ibhidlika ngokuphepha ibe ngamanzi ahlanzekile nomoyampilo phakathi kwamahora angama-24 kuya kwangama-48.

Isixazululo Esihlala Njalo: Ukufaka Umoya Nokulawula Ukushisa

Ukuhlenga isivuno kanye kuyisivivinyo; ukusihlenga njalo ngemva kwamasonto amabili kubulala intshisekelo yabafundi. Ukuze wenze isistimu yakho yaseklasini imelane ne-Pythium, kufanele ulungise ukufakwa komoya kanye nezinga lokushisa unomphela.

Faka itshe lomoya lase-aquarium (airstone)

Ukuthembela kuphela kusiphethu esincane noma ukuconsa kwamanzi abuyayo avela ephampini yakho yamanzi ecwiliswayo akuvamile ukwanela lapho amazinga okushisa kwamanzi enyuka ngaphezu kuka-22°C. Udinga uhlelo lokufaka umoya ngomshini olusebenza njalo.

Iphampu yomoya ye-aquarium eyisisekelo enezimbobo ezimbili (elinganiselwa ku-3W kuya ku-5W) ehambisana namatshe amabili omoya e-ceramic angama-50 mm ibiza phakathi kuka-R15 no-R300 kunoma yisiphi isitolo sezilwane sasekhaya. Beka amatshe omoya phansi ethangini ngqo ngaphansi kwezimpande. Ukuphuma okuqhubekayo kwamagwebu amancane kakhulu kuphoqa umoyampilo oncibilikile ukuba ungene kungxube yezakhi zomsoco futhi kugqugquzela ingaphezulu lamanzi ngokomzimba, okuvimbela ukwakheka kwezindawo ezingenamoya (anaerobic) ezizungeze inetha lezimpande.

Ukuhlola okulula: uma ithangi lakho libukeka njengamanzi edamu anganyakazi, lishoda ngomoyampilo. Kufanele libonakale ligxaza ngamagwebu amahle usuku lonke lwesikole nasebusuku.

Lawula izinga lokushisa lethangi ngesabelomali sesikole

Abalimi bezohwebo basebenzisa izipholisa-manzi ezibizayo ezibiza izinkulungwane zamarandi. Ikilasi lesikole alikudingi lokho. Kunalokho, sebenzisa izindlela zokuvikela ukushisa ezingabizi:

• Faka izinto ezivikela ukushisa ethangini: Amakhithi amaningi ezikole asebenzisa amabhokisi okugcina acwebezelayo noma amnyama. Ipulasitiki ecwebezelayo ivumela ukukhanya ukuba kungene, okubangela ukwanda kwe-algae eluhlaza edla ukubola kwezimpande; ipulasitiki emnyama imunca ukushisa okuvela eklasini. Songa izindonga zesivalo nethangi nge-foil bubble-wrap evikela ukushisa (etholakala ngemitha ezitolo zezakhiwo) noma beka ithangi ngaphakathi kwebhokisi lamakhadibhodi elinombala okhanyayo elifakwe i-styrofoam ngaphakathi.
• Ligcine likude naphansi okufudumele: Ehlobo, ukhonkolo lwezitezi ezingenhla lubamba ukushisa okukhulu kakhulu. Phakamisa ithangi lakho phezu kwezicucu zamapulangwe noma iphalethi lokhuni ukuze umoya ojwayelekile uzungeze ngaphansi kwalo.
• Iqhinga lebhodlela lamalitha ayi-2 eliqandisiwe: Ngezinsuku okubikezelwe ukuthi zizodlula ku-30°C, yenza abafundi bantantise ibhodlela lesiphuzo elihlanzekile eliqandisiwe elingamalitha ayi-2 lamanzi ethangini ekuseni. Linciphisa kancane kancane amazinga okushisa kwamanzi ngo-2°C kuya ku-4°C phakathi namahora amane ashisa kakhulu osuku lwesikole ngaphandle kokunciphisa ibhalansi ye-EC yezakhi zomsoco. Lishintshe ufake elinye ibhodlela elivela efrijini legumbi lothisha emini uma kudingeka.

Uma uhlelela ingadi yokudla yesikole ebanzi noma iphrojekthi yekharikhulamu lapho ukuqapha imvelo okuzenzakalelayo kubalulekile, izinhlelo zethu ze-hydroponic kanye namakhithi ethu okulima okuhlakaniphile kuhlanganisa izinzwa zedijithali zokushisa ezingabizi kakhulu kanye namaswishi ezinga lamanzi ukuze abafundi bakwazi ukurekhoda izimo zethangi ngokuzenzakalelayo ngaphambi kokuba izimpande zonakale.

Ukuguqula Ukwehluleka Kube Isifundo Sesayensi

Ukuqubuka kokubola kwezimpande akudingeki kuthathwe njengenhlekelele yaseklasini. Kuwuphenyo oluvelele lomhlaba wangempela lwabafundi beSayensi Yemvelo (Natural Sciences) neSayensi Yezempilo (Life Sciences) eSigabeni Esiphezulu (Senior Phase). Yenza ikilasi lakho lisebenzise ishadi eliyisisekelo lomoyampilo oncibilikile, lilandelele izinga lokushisa lethangi phakathi nomjikelezo wamahora angama-24 lisebenzisa inzwa elula ecwiliswayo, futhi liqhathanise izimpande ezikhuliswe ngamagwebu asebenzayo nebhasikidi elingaphansi kokulawulwa (control tote) elingenayo iphampu yomoya.

Lapho abafundi sebebonile ukuthi izimpande kumele ziphefumule njengoba amaqabunga kumele enze i-photosynthesis, ukulawula izinga lokushisa kwamanzi nokuhamba komoya kuyayeka ukuba ngumsebenzi oyisicefe kodwa kuba ngumthetho oqondakalayo webhayoloji yezolimo.