Kuthekera kwa zokolola za mtedza nthawi zambiri kumakhala kwakukulu pamene nthaka pH imachokera pa 5.8 mpaka 6.2. Nthaka yambiri ku Malawi ili ndi pH yotsika kwambiri kuposa momwe ilili bwino, ndipo zokolola ndi ubwino wa mtedza sizingafike ponseponse mosasamala kanthu za zoikamo zina pokhapokha nthaka pH itakwezedwa pa mlingo wovomerezeka. Pamene pH ya nthaka ili yotsika kwambiri, mtedza sungathe kuyankha bwino mankhwala a Bradyrhizobia okhala ndi BNF kapena kuonjezera calcium mu mawonekedwe a gypsum (calcium sulfate).

Zinthu monga boron, manganese, molybdenum, ndi zinki zimatha kukhudzidwa ndi pH ya nthaka. Kulinganiza koyenera kwa zinthu zonse kumafunikira nthaka pH mozungulira 6.0 ya mtedza. Pamene nthaka pH ili pansi kuposa 5.5, mabakiteriya omwe ali mu inoculant nthawi zambiri sakhala ndi moyo.

Laimu ayenera kuthiridwa miyezi ingapo asanafese mtedza kuti achepetse acidity. Mlingo wa laimu wofunika kukweza pH kufika pa 5.5 kapena kupitilira apo umadalira mulingo wa pH wapano komanso kuthekera kophatikiza laimu kumtunda wa 25 cm wadothi. Ngakhale kuti mizu ya mtedza imakula mozama kuposa masentimita 25, kuchepetsa acidity ya dothi m'malo otsetsereka ndikofunikira. Kuti muwonjezere pH ya nthaka ndi mayunitsi a 0.5 (mwachitsanzo, kuchulukitsa pH ya nthaka kuchoka pa 5.0 mpaka 5.5) kumafuna pafupifupi 1,000 kg/ha ya laimu wa dolomitic powulutsa. Kuonjezera nthaka pH kuchoka pa 5.0 kufika pa mlingo wofunidwa wa 6.0 kumafuna pafupifupi 2,000 kg/ha.

Dothi lomwe linatengedwa m’chaka cha 2021 kuchokera m’minda yoposa 850 ya chimanga, mtedza, ndi soya m’maboma asanu omwe anasankhidwa (Lilongwe, Salima, Ntchisi, Kasungu, ndi Mzimba) linasonyeza kuchuluka kwa pH ya pH koma yochuluka inali pakati pa 4.0 ndi 6.0. Kuyang'ana koyamba kunawonetsa kuti pH ya nthaka inali pafupifupi 5.2 yomwe ndiyotsika kuposa momwe ilili bwino. Zolowetsa monga zotsekemera sizigwira bwino pansi pa nthaka yotsika pH ndipo zimakhala zogwira mtima kwambiri pamene pH ili pafupi ndi 6.0.

Kuchuluka kwa Dothi ndi Zakudya Zam'mera

Mtedza ukhoza kupindula ndi chonde chotsalira ndipo nthawi zina sangafunike feteleza wowonjezera ngati mbewuyo yabzalidwa pamalo osamalidwa bwino omwe kale adathiridwapo ndi fetereza. Komabe, ngati chonde cha mbadwa chili chochepa, feteleza wowonjezera amachulukitsa zokolola. Dothi zambiri muulimi wodyetsedwa ndi mvula zimakhala ndi phosphorous yochepa kwambiri, kotero kuti mbeu zizikhala bwino komanso zokolola zambiri, alimi akulimbikitsidwa kuthira superphosphate asanafese kapena asanafese. Kugwiritsiridwa ntchito kwa superphosphate imodzi, kumapatsa mbewuyo phosphate, sulphate ndi calcium zomwe ndizofunikira pakukula ndi kukula kwa mbewu.

Nthawi zambiri, mtedza umachita bwino ukangodzala chimanga kapena fodya wodzala ndi feteleza. Feteleza wa phosphorus, calcium ndi sulfure monga 23:21:0+4S atha kuonjezera zokolola za mtedza ngakhale atathira mbewu zakale. Superphosphate ya 100kg/ha yomwe imayikidwa pobzala imalimbikitsidwa kumunda wa mtedza m'minda yomwe ili ndi chonde chochepa. Feteleza ayenera kuikidwa pa bande pamphepete, kapena kufalitsa pa dothi ndi kulimidwa pansi asanafese. Kafukufuku mu 2020 ndi 2021 akuwonetsa kusagwirizana, koma nthawi zambiri zokolola zimawonjezeka kuchokera pakugwiritsa ntchito feteleza wachilengedwe. Zolemba izi sizinawonekere kukhala zogwirizana m'mitundu yonse ndipo kafukufuku wochulukirapo akufunika.

Biological Nitrogen Fixation (BNF)

Zomera zambiri za nyemba, kuphatikizapo mtedza, zimatha kupanga ubale wabwino ndi mabakiteriya ena (Bradyrhizobia spp.) omwe amapezeka m'nthaka. Mabakiteriya amawononga mizu ya zomera ndikutenga nayitrogeni kuchokera mumlengalenga ndikupangitsa kuti mbewuyo izimere (BNF) posinthanitsa ndi zakudya kuchokera ku mbewu. Kusinthanitsaku kumachitika m'timinofu tating'onoting'ono topezeka pamizu ya zomera. BNF yogwira imatha kutsimikiziridwa ndi kudula kotsegula kuti muwone ngati pali mtundu wofiira kapena wa dzimbiri, zomwe zimasonyeza kutembenuka kwa nayitrogeni. Mitundu yeniyeni ya Bradyrhizobia yazindikirika kuti iwonjezere kukolola kwa mtedzawu ndipo imapezeka ngati mankhwala oteteza ku malonda omwe nthawi zambiri amakutidwa kumbewu musanabzalidwe.

Mosiyana ndi soya, zomwe zimafunikira mtundu wina wa mabakiteriya a BNF, mtedza ukhoza kapena sangapindule ndi inoculant. Inoculant imatha kukulitsa nodulation ndi kukonza nayitrogeni, zomwe zimapangitsa kuti pakhale zokolola zambiri. Komabe, m’minda imene mtedza unalimidwapo kale, mabakiteriya ambiri angakhale kale okwanira, zomwe zimapangitsa kuti njuchi zikhale zosafunikira. Kapena, ngati nthaka pH ili yotsika kwambiri, inoculant ikhoza kukhala yosagwira ntchito mpaka pH itasinthidwa (njira yofotokozedwa kwina mu bukhuli). Mayesero aposachedwapa omwe achitika m'Malawi muno akuwonetsa phindu logwiritsa ntchito mankhwala otsekemera komanso kuchulukitsa kwa nayitrogeni wachilengedwe komanso zokolola, koma izi sizinali zowona m'malo aliwonse kapena pamitundu iliyonse. Zomwe zimachitika pa data zimawonetsa kufunika kogwiritsa ntchito inoculant, makamaka ngati nthaka pH ili pamwamba (pamwamba pa 5.5).

Popeza kuti majeremusi ndi zamoyo, amathanso kuonongeka ndi kusagwira bwino ntchito, monga kuwasunga pakatentha kwambiri. Pogwiritsira ntchito inoculant, alimi ayenera kupeza katundu wawo kuchokera kwa wogulitsa wodalirika, kutsatira malangizo a wopanga mosamala, perekani inoculant mwamsanga musanabzale ndikugula zatsopano chaka chilichonse kuti muwonetsetse kuchuluka kwa mabakiteriya amoyo. Mankhwala ophera tizilombo amatha kuwononga ntchito yoteteza, kotero alimi omwe amagwiritsa ntchito zonsezi ayenera kutsatira malangizo a opanga mosamala. Kukhudzana mwachindunji ndi feteleza opangidwa m'nthaka kungathenso kuwononga thanzi labwino, kotero alimi ayenera kuganizira momwe feteleza amagwiritsidwira ntchito pobzala. Osathira feteleza mumzere momwe angakhudzire mbewu.

Zithunzizi zikuwonetsa minyewa ndi mtundu wofiyira kwambiri kapena dzimbiri zomwe zikuwonetsa magwiridwe antchito oyenera

Ikani Calcium pa Maluwa Oyamba

Calcium ndiye michere yochepetsetsa kwambiri mu dothi lamchenga komanso komwe mitundu yambewu yapakati kapena yayikulu monga ya Virginia imabzalidwa. Mitundu yambewu yayikulu ya Virginia imakhala ndi maso akulu omwe nthawi zambiri amafunikira calcium yochulukirapo kuti apangire kernel ndikukula kwa mbewu kuposa momwe mitundu yaing'ono ya ku Spain imachitira. Kuthira pamwamba ndi gypsum pamene 30% ya zomera zachita maluwa kumathandiza kukonza kusowa kwa kashiamu ndi kuchepetsa kuchuluka kwa makoko a mtedza wopanda maso kapena maso osalongosoka. Gypsum iyenera kuyikidwa pamlingo wa 200 kg/ha mwachindunji pansi pa mbewu pomwe zikhomo zidzalowa munthaka. Pansi pa nthaka yotsika pH ya nthaka, yomwe imakonda ku Malawi, kuthira gypsum kumachepetsa zokolola. Mwachitsanzo, deta yochokera ku USA inasonyeza kuti kuyankha kwabwino kwa gypsum kumachitika pamene nthaka pH ili pafupi 6.0. Pa pH kuzungulira 5.5 kutsika kwa zokolola kunadziwika pamene gypsum anagwiritsidwa ntchito, pa pH 5.2 panalibe yankho ku gypsum, ndipo pH 4.5 gypsum yowonjezera zokolola. Zotsatira zina zikuwonetsa kuti kuchuluka kwa ma gypsum kuposa omwe akulangizidwa pano kumachepetsanso zokolola pomwe pH inali 5.5. Zotsatirazi zikuwonetsa kuti kufotokozera bwino kwa gypsum rate ndi kugwiritsa ntchito pH.

Kafukufuku amene anachitika mu nyengo yakukula ya 2020-2021 pa mphamvu ya boron ndi kashiamu anaonetsa zotsatira zabwino pa zokolola m’madera awiri, mitundu yonse ya Chitala ndi CG9, komanso ikagwiritsidwa ntchito pamasiku osiyanasiyana m’minda ya pH pafupi ndi 6.0.

pH ndi chonde cha nthaka