Iindlela Zokumeta Ubumanzi boMhlaba

Ukwenzela Ukubeka Amaxesha Okunkcenkceshela

©Louise Brodie
Kubalulekile ukubazu ubumanzi bomhlaba ukuze umlimi ankcenkceshele ngexesha elifanelekileyo. Nokuqinisekisa ukuba kukho amanzi oneleyo emhlabeni ukuze iingcambu zesityalo zikwazi ukufunxa amanzi.
Ukumeta ubumanzi bomhlaba kuqinisekisa ukuba izityalo azibi phantsi koxinzelelo kwaye akubikho lahleko yemveliso ngenxa yokunqongophala kwamanzi emhlabeni.
Kusetyenziswa iindlela nezixhobo ezahlukeneyo ukuhlola umhlaba ukuze kuqinisekiswe ukuba izityalo zikhula ngendlela efanelekileyo. Ezona ndlela ixhaphakileyo neyenzelwa ukubeka amaxesha okunkcenkceshela zezi:
The Neutron Probe Meter
Gypsum block
Tensiometer okanye irrometer
Inkangeleko nokuvakala komhlaba
Time Domain Reflectometry (TDR) Probe

iNeutron Probe Meter

iNeutron Probe Meter imeta ubumanzi bomhlaba ngokuthi isasaze iineutrons emhlabeni. Esi sixhobo sine probe encamini yaso nehamba iyekuphela kwi rate meter box. Le probe iqulathe ineutron ekhawulezayo, nenokuba ngumxube we radium kunye ne beryllium okanye iAmericium kunye ne beryllium.
Imibhobho ye aluminium enobude obungama 500 mm ukuya kuma 1 000 mm long ze ibengama 32 mm ukuvuleka kunye nemisekelo evalekileyo iye ibekwe entsimini ekufunwa ukumetwa kuyo ubumanzi bomhlaba. Kusetyenziswa imibhobho emifutshane kwizityalo ezineengcambu ezingaziki kangako emhlabeni. Ze kusetyenziswe emide kwezo zinengcambu ezingena nzulu emhlabeni okanye kwezi zineengcambu ezomeleleyo.
Le neutron probe iye yehliselwe kulemibhobho ngobunzulu obudingekayo, ze iineutrons ezibalekayo ziphume kule probe. Iineutrons ziye zisasazeke emhlabeni. Xa ezi neutrons zidibana ne hydrogen atom yamanzi, isantya sezi neutrons siyacutheka ze irate meter ibale inani lee neutrons ezicothayo. Inani lee neutrons ezicothayo lilinganiswa nee molecule zamanzi emhlabeni. Ngokufaka le nkcukacha kwi software, ubumanzi bomhlaba bubonakaliswa kwi calibration curve ebonakalisa inani lee neutrons ezicothayo.
Imivuzo
Iziphumo zometho ziyakhawuleza kwaye iyaqhubekeka nokumeta. Ukusebenzisa iNeutron Probe akudingi nokuba umhlaba uphazanyiswe kwaye ingameta umhlaba omkhulu (does (ama 200 mm ukuya kuma 400 mm ejikeleze imibhobho ye probe) kunezinye iindlela/izixhobo.
Imiqobo
Ukusebenzisa ineutron Probe kuxabisa kakhulu. Isebenzisa riadioactive source kwaye idinga ukumane ilungiswa ngabasebenzi abaqeqeshiweyo. Umeto oluthe ngqo lwemihlaba engekho nzulu lubayingxaki ngoba ezi neutrons zibalekayo zingacothiswa zezinye iihydrogen atoms ezikhoyo emhlabeni kwakunye nee atoms zentsalela zezinye ii-element eziqhele ukubakhona kuma 20mm omhlaba ongaphezulu. Oku kukhokelela ekubeni uqikelelo lobumanzi bomhlaba lubaxeke.

iGypsum, Clay okanye iPlaster yeParis Blocks

Lama bhloko amile okwe rekthengile anobude obumalunga nama 550 mm, ama 375 mm ububanzi kunye nama 20 mm ubudeki. iGypsum, clay okanye iplaster ye Paris blocks zisetyenziswa ukumeta ubumanzi bomhlaba. Ukwenza oku kubekwa ezi zitena kanye kulendawo kufuna ukuhlolwa ubumanzi kuyo. Kuye kwakhiwe iielectrodes ezimbini ziqelelaniswe kangaka ngama 20 mm phakathi kwezi zitena.
Lendlela yokumeta isebenza ngombane. Xa umbane uhamba ngezi electrodes zimbini, indlela ohamba ngayo uhambelana nobumanzi bezitena ezo. Xa ezi zitena zimanzi indlela ohamba ngayo lombane ibaphezulu. Ubukhulu becala, ukuba ezi electrodes zibonisa malunga nama 400 ukuya kuma 600 ohms okutshitshiliza kombane kunye malunga nama 50 000 kwindawo apho isityalo ingasenakho ukufunxa amanzi emhlabeni ukuze iziphilise. Esi sibalo sithathwa nge Wheatstone Bridge Bouycos.
Fakela igypsum kumhlaba ongaphazamisekanga.
Imiqobo
Iigypsum blocks azinakuthenjwa ncam ngokuhlala xa zifakwe kwimihlaba emanzi.

Tensiometer/Irrometer

©Louise Brodie
Itensiometer sisixhobo esimeta indlela amanzi agcinwe ngayo ngumhlaba. Iqulathe, kwi ncam yayo, ikomityi eyi 8 cm eyenziwe ngomdongwe enombhobho ofakelwe kwintsimbi engu mbhobho onendawo efunxayo ngaphezulu. Le nkonkxa ke iye igalelwe amanzi kumngxunya ongaphezulu aze aphume ngencam yomdongwe. Iye ivulwe nge vacuum gauge xa ifakwa emhlabeni.
Faka itensiometer ngokugqobhoza umngxunyana nje olingene ukuba kungene lombhobho kwindawo enengcambu zesityalo. Kufanele ukuba kungabikho kubola kulo mbhobho. Kufuneka lombhobho ungagoqozi kulo mngxuma. Ubumanzi obusuka kule nkonkxa buzakukhutsha kunye nomhlaba owomileyo. Oku kwenza ukufunxeka kulo mbhobho neye imetwe ngale gauge. Xa kufikelelwe kuxinzelelo olufunekayo, umhlaba kufuneka unkcenkceshelwe. Le vacuum gauge ibonakalisa ukuba uxinzelelo lulingana ne one atmosphere enye kodwa yona ingakwazi ukumeta i-atmosphere efikelela ku 0.85 kuphela.
Imivuzo
Itensiometer ayisokolisi kwaye kulula ukuyifaka ube sele ubona ubumanzi bomhlaba kwangoko. Kuluncedo ukubeka amaxesha okunkcenkceshela izityalo ezidinga ukunnkcenkceshelwa rhoqo.
Imiqobo
Le tensiometer ikwazi ukuhlola kuphela ubumanzi bomhlaba obufikelela kwi 0.85 atmospheres logama ubumanzi bomhlaba bungafikelela kwisibalo esiyi atmosphere enye. Itensiometer ikwasebenza kakuhle kwimihlaba eyisanti kunaleyo isindayo ingumdongwe.

Inkangeleko Nokuvakala Komhlaba

Ukuba akukho nanye indlela ekhoyo kwezi zikhankanywe ngasentla, le ndlela yokuqikelela ubumanzi bomhlaba.ingasetyenziswa ngelokuncamela. Oku kungenziwa ngoku thatha isampuli zomhlaba lo uhlolwayo. Le sampuli iye ikhanywe ngesandla, kwaye inkangeleko nokuvakala komhlaba kuthathelwa ingqalelo. Ngokusebenzisa le ndlela, akukwazeki ukubona bumanzi bomhlaba obuthe ngqo.

Time Domain Reflectometry (TDR) Probes

©Louise Brodie
TDR probes yindlela entsha yokubeka amaxesha okunkcenkceshela. Le ndlela imeta ixesha elithathwa yi electrical pulse ukufika kubude bentsimbi ezifakwe emhlabeni.
iTDR probes zivamise ukusetyenziswa kwizindlu zokutyala (greenhouses) kwaye zikuchana ncam ukumeta ubumanzi. Kodwa ke zizixhobo ezixabisa kakhulu ukuba zingasetyenziswa kwimihlaba emikhulu.

Translated by Zizipho Silwana