Njira Yoyendera Nayitrogeni: Moyo Wachilengedwe Uli Pamodzi
Kuzungulira kwa nayitrogeni ndi chimodzi mwa zinthu zofunika kwambiri pa dziko lapansi, zomwe zimaphatikizapo kuyenda kwa nayitrogeni m'njira zosiyanasiyana pakati pa mlengalenga, nthaka, madzi, ndi zamoyo. Nayitrogeni ndi chinthu chofunikira kwambiri, chomwe chimapanga pafupifupi 78% ya mlengalenga wa Dziko lapansi mu mawonekedwe a mpweya wa nayitrogeni (N2). Ngakhale kuti ndi wochuluka, mtundu uwu wa nayitrogeni sungagwiritsidwe ntchito mwachindunji ndi zamoyo. Chifukwa chake, kuzungulira kwa nayitrogeni kumachita gawo lofunika kwambiri pakusintha nayitrogeni wa mumlengalenga kukhala mitundu yomwe zomera ndi nyama zingagwiritse ntchito. Nkhaniyi iwunikanso magawo akuluakulu a kuzungulira kwa nayitrogeni.
### 1. Kukhazikika kwa Nayitrogeni (Kukhazikika kwa Nayitrogeni)
Gawo loyamba mu kayendedwe ka nayitrogeni ndi kukhazikika kwa nayitrogeni, njira yomwe mpweya wa nayitrogeni wozungulira (N2) umasandulika kukhala ammonia (NH3) kudzera mu ntchito ya tizilombo toyambitsa matenda kapena kudzera mu njira zosasinthika monga mphezi.
Pali mitundu iwiri ikuluikulu ya nayitrogeni:
– Kukhazikika kwa Zamoyo: Kumachitika ndi mabakiteriya ena, kuphatikizapo a mtundu wa Rhizobium, omwe amakhala m'mizu ya nyemba monga nyemba ndi alfalfa. Mabakiteriyawa ali ndi enzyme ya nitrogenase, yomwe imatha kuswa mgwirizano wamphamvu pakati pa maatomu a nayitrogeni mu N2 ndikuisintha kukhala ammonia.
– Kukhazikika kwa Abiotic: Njirayi imachitika mwachilengedwe kudzera mu mphezi yomwe imapereka mphamvu zokwanira zothyola mgwirizano wa N2 kukhala maatomu a nayitrogeni, omwe kenako amachitapo kanthu ndi mpweya mumlengalenga kuti apange nitrite ndi nitrate zomwe zimatengedwa kupita pansi ndi mvula.
### 2. Kuphatikizika kwa Ammoni (Kuphatikizika kwa Ammoni)
Kuphatikizika kwa ammonia, komwe kumadziwikanso kuti kuwola kapena mineralization, ndi njira yomwe zinthu zakufa zamoyo, kaya zomera kapena nyama, zimasweka ndi tizilombo toyambitsa matenda tosaprophytic, zomwe zimapangitsa ammonia (NH3) kapena ammonium ions (NH4+). Zinthu zamoyozi zimaphatikizapo mapuloteni, DNA, ndi zinthu zina za nayitrogeni m'thupi la zamoyo. Zamoyo zikafa ndipo kuwola kumachitika, nayitrogeni m'zinthu zamoyo imabwereranso m'nthaka ngati ammonia, yomwe ingagwiritsidwenso ntchito ndi zomera.
### 3. Kupatsa mphamvu kwa madzi m'thupi
Nitrification ndi njira ya magawo awiri yomwe imasintha ammonia (NH3) kapena ammonium ion (NH4+) kukhala nitrite (NO2-) kenako nitrate (NO3-). Njirayi imachitika pogwiritsa ntchito mabakiteriya omwe amapatsa nitrite:
– Gawo loyamba: Kusungunuka kwa ammonia kukhala nitrite ndi mabakiteriya otchedwa Nitrosomonas.
– NH3 + O2 → NO2- + H2O + H+
– Gawo lachiwiri: Kuwonjezeka kwa nitrite kukhala nitrate ndi mabakiteriya osiyanasiyana, monga Nitrobacter.
– NO2- + 1/2 O2 → NO3-
Nitrate yomwe imachokera imatha kuyamwa ndi mizu ya zomera ngati michere yofunika kapena kubwezeretsedwanso kukhala mpweya wa nayitrogeni waulere, kutengera momwe zinthu zilili.
### 4. Kugwirizana
Kusakaniza ndi njira yomwe zomera zimayamwa nitrate (NO3-) kapena ammonium (NH4+) kuchokera m'nthaka kudzera mu mizu yawo. Nitrate yomwe imayamwa imasinthidwa kukhala ammonia ndi enzyme nitrate reductase m'maselo a zomera. Ammonia iyi imagwiritsidwa ntchito popanga ma amino acid, ma nucleotide, ndi mankhwala ena a nayitrogeni ofunikira kuti zomera zikule ndikukula. Njirayi imaperekanso gwero lofunikira la nayitrogeni kwa nyama zomwe zimadya zomera izi, zomwe zimapangitsa kuti nayitrogeni ipite patsogolo ku trophic mu chilengedwe.
### 5. Kuchepetsa mafuta m'thupi
Kuchepetsa mphamvu ya nitrite ndi njira yomwe nitrate (NO3-) imasinthidwa kukhala mpweya wa nayitrogeni (N2) kapena mpweya wa nitrous oxide (N2O) kudzera muzochita zingapo zosasinthika zomwe zimachitika chifukwa cha mabakiteriya ochepetsa mphamvu ya nitrite, monga Pseudomonas ndi Clostridium.
– NO3- → NO2- → NO → N2O → N2 (g)
Kuchotsa madzi m'thupi kumachitika makamaka m'malo omwe madzi samayenda bwino, monga m'nthaka yodzaza ndi madzi kapena mulu wa zinyalala zachilengedwe. Njirayi ndi yofunika chifukwa imathandiza kupewa kuchuluka kwa nitrates m'chilengedwe, zomwe zingayambitse kufalikira kwa madzi m'madzi.
### 6. Udindo wa Anthu pa Kuzungulira kwa Nayitrogeni
Zochita za anthu zimakhudza kwambiri kayendedwe ka nayitrogeni yachilengedwe. Kugwiritsa ntchito feteleza wa nayitrogeni wopangidwa muulimi kumathandiza kuwonjezera kukhazikika kwa nayitrogeni, komanso kumathandizira kuipitsa chilengedwe kudzera mu madzi omwe amatha kuwononga chilengedwe m'madzi. Kuyaka kwa mafuta ndi ntchito zamafakitale kumapanganso ma oxide a nayitrogeni, omwe amathandizira kuipitsa mpweya, mvula ya asidi, ndi kusintha kwa nyengo.
### Mapeto
Kuzungulira kwa nayitrogeni ndi chitsanzo chabwino kwambiri cha momwe zinthu zofunika zimayendera m'chilengedwe, kuonetsetsa kuti zinthu zonse zofunika zikuyenda bwino. Kuyambira kukhazikika kwa nayitrogeni, kuyika kwa ammonization, nitrification, assimilation, ndi denitrification, gawo lililonse limagwira ntchito yolumikizana komanso yofunika kwambiri. Kumvetsetsa ndi kuzindikira zovuta za kuzungulira kwa nayitrogeni sikuti ndikofunikira kokha pa sayansi ya zachilengedwe komanso ku khama lathu loyang'anira zachilengedwe ndi chilengedwe mokhazikika. Tikadziwa bwino za kuzungulira kumeneku, titha kuchitapo kanthu kuti tichepetse zotsatira zoyipa za zochita za anthu ndikusunga bwino zachilengedwe za chilengedwe chathu.
