Cov kws tshawb fawb soj ntsuam txog 30-xyoo pob kws- taum soy-kev sim hloov cov nplej hauv Michigan pom tias lub sijhawm ntawm kev cog qoob loo thiab huab cua kub yog qhov muaj zog tshaj plaws ntawm cov av nitrogen muaj nyob rau hauv npog-cropped agroecosystems, muab cov neeg cog qoob loo tshiab kev nkag siab txog kev tswj cov qoob loo.
Txoj kev tshawb no, ua nyob rau ntawm Kellogg Biological Station Ntev-Lub Sijhawm Ecological Research site, siv cov qauv kev kawm hav zoov random los tshuaj xyuas cov nitrogen mineralization dynamics hauv kev txo qis - cov tswv yim thiab cov organic qoob loo ntawm xyoo 1990 thiab 2020. Cov kws tshawb fawb pom tias av inorganic nitrogen, tshwj xeeb tshaj yog cov nitrate (NO3−-) cov qoob loo sai sai tom qab cog qoob loo, tshwj xeeb tshaj yog nitrate (NO3−-}) 50 hnub tom qab, tshwj xeeb tshaj yog thaum nruab nrab txhua hnub kub siab tshaj 12 degree.
Cov kev tshawb fawb tau tsom mus rau cov qoob loo cog qoob loo uas siv rau hauv cov pob kws cog qoob loo thiab tshuaj xyuas seb huab cua zoo li cas, npog cov qoob loo biomass, av noo, thiab kev tswj hwm kev cuam tshuam rau kev tso tawm nitrogen. Raws li kev tshawb pom, hnub tom qab npog cov qoob loo txiav tawm tsis tu ncua yog qhov tseem ceeb tshaj plaws cuam tshuam rau ob qho tib si nitrate thiab ammonium muaj, thaum qhov kub thiab txias yog qhov tseem ceeb thib ob ntawm cov qauv. Txoj kev tshawb no qhia tau hais tias cov nitrogen tso tawm tau tsav los ntawm kev sib cuam tshuam ntawm cov yam tseem ceeb es tsis yog los ntawm ib qho kev sib txawv ntawm ib leeg.
Cov kws tshawb fawb tau hais tias qhov kev tshawb pom tuaj yeem pab cov neeg ua liaj ua teb zoo dua synchronize nitrogen tso tawm los ntawm npog cov qoob loo nrog cov qoob loo xav tau, muaj peev xwm txo qis kev cia siab rau cov chiv chiv thiab txo cov kev cuam tshuam ib puag ncig xws li nitrate leaching thiab nitrous oxide emissions. Txoj kev tshawb no tseem pom tau tias cov av nitrate feem ntau peaked thaum lub sij hawm cov pob kws cov qoob loo loj hlob sai ua ntej yuav poob vim cov nroj tsuag absorbed nitrogen.
Cov qauv kev kawm tshuab tau piav qhia txog 35% ntawm qhov sib txawv ntawm cov av nitrate nyob rau lub caij nyoog loj hlob, thaum qhov kev kwv yees qhov tseeb rau ammonium qib qis dua. Txawm hais tias muaj qhov sib txawv ntawm cov khoom tsim tawm ntawm qhov txo qis - cov tswv yim thiab cov tshuab organic, ob lub tshuab tau pom qhov zoo sib xws raws caij nyoog nitrogen dynamics, qhia tias qhov kub thiab lub sij hawm ua si tseem ceeb hauv nitrogen mineralization tsis hais txog kev tswj xyuas.
Cov kws tshawb fawb tau sau tseg tias npog cov qoob loo biomass nws tus kheej muaj qhov tsis muaj zog ntawm nitrogen muaj ntau dua li qhov xav tau, tej zaum vim tias qib biomass txawv me ntsis ntawm xyoo piv nrog cov huab cua. Lawv tau hais ntxiv tias yav tom ntej kev ua haujlwm sib koom ua ke nrog cov ntaub ntawv pov thawj nrog cov txheej txheem- cov qauv tsim tuaj yeem txhim kho kev kwv yees thoob plaws cov av sib txawv thiab huab cua.
Txoj kev tshawb no yog coj los ntawm Rabin KC nrog co-sau G. Philip Robertson thiab Sieglinde Snapp. Cov nyiaj tau los yog muab los ntawm National Science Foundation Long-Lub Sijhawm Ecological Research Program, USDA Ntev-Term Agroecosystem Research program, thiab Michigan State University AgBioResearch.
