Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2005
Forfattere
Anne Falk Øgaard Tore KrogstadSammendrag
Potassium (K) release from sources that are not initially exchangeable is attributed to depletion of interlayer K of micas and clay minerals or weathering of feldspars. The aim of the present study was to estimate the K release from interlayer K. Soil samples from 17 field experiments in ley on a range of mineral soils in Norway were used in the study. The change in K fixation capacity was used as an estimate of depletion of interlayer K. It was assumed that the increase in K fixation capacity during three years of cropping was equivalent to the amount of K depleted from the interlayer positions. Mean K fixation increased in the majority of the soils during three years of grass cropping both with and without K application. The increase in K fixation indicated that without K application the K uptake from interlayer K amounted to 43, 28 and 26% of the K yield for clay soils, high K sandy soils and low K sandy soils, respectively. Including K uptake from exchangeable K in the topsoil and from subsoil, the explained K uptake amounted to 79, 69 and 81% for the three groups of soil, respectively. Simple linear regression analyses showed that the change in K fixation during three years of grass cropping was best explained by the percentage of clay in the soil.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Laboratory incubations with varying O2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. 15N-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N2+N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N2+N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat. The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.
Forfattere
Pål Tore Mørkved Anne Kristine Søvik Bjørn Kløve Lars R. BakkenSammendrag
Laboratory incubations with varying O-2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. N-15-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N-2 + N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N-2 + N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora. Laboratory incubations with varying O-2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. N-15-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N-2 + N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N-2 + N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.
Forfattere
Pål Tore Mørkved Anne Kristine Søvik Bjørn Kløve Lars R. BakkenSammendrag
Laboratory incubations with varying O2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. 15N-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N2 þ N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N2 þ N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat. The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only forshell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.
Forfattere
Trond MæhlumSammendrag
Det er ikke registrert sammendrag
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Forfattere
Lars Nesheim Gustav Fystro Olav HarboSammendrag
På tre forsøksfelt i ung eng vart det årleg tilført frå 0 til 5 kg fosfor per dekar i dinatriumhydrogenfosfat (Na2HPO4 x 2H2O). Dette stoffet vart nytta for å unngå samanblanding av verknad av svovel i superfosfat, som er mykje brukt i tidlegare gjødslingsforsøk med fosfor. Målsettinga med feltforsøka var å finne kritiske verdiar for fosforinnhald med omsyn på plantevekst under praktiske tilhøve. Sjølv til dels sterk P-gjødsling førte berre til liten auke i opptak av P i planter, og også til små avlingsutslag, på jord med relativt lite tilgjengeleg fosfor. Slike uventa små utslag medførte at samanhengen mellom plantene sin P-status og avlingsutslag vart dårleg bestemt. Det vart likevel observert ein trend til avlingsreduksjon ved låge P/N-verdiar. Av i alt 10 kg tilført P i gjødsel over to år vart berre 9 % funne att i avlinga.
Forfattere
Olav Lode Kjetil Sola Bente Stensland Bjørn EkebergSammendrag
Feltlysimeterforsøk i jordbær der det er nytta planteverniddel mot ugras, skadedyr og plantesjukdomar er utført på Foss gard i Lier under dagleg leiing av Landbrukets Fagsenter Østlandet. Hovudmålet til prosjektet var å sjå på produksjonssystem som var retta mot miljøvenleg plantevernpraksis og få dokumenter kunnskap om bruk av plantevernmiddel i jord. Artikkelen er konsentrert om restmengdere av plantevernmiddel i grøftevatn og overflatevatn i dyrkingsforsøk der det er nytta svart plast med dryppvatning og mattekultur (halm) der det er bruka vatnspreiar. Det er Pesticidlaboratoriet til Planteforsk som har analysert vatnprøvane.
Forfattere
Kim JohansenSammendrag
I perioden 1997-2004 ble det oftere påvist plantevernmiddelrester i norskdyrkede jordbær enn i importerte. Men de siste årene har trenden snudd. Norskdyrkede jordbær hadde færre påviste plantevernmiddelrester i 2004 enn importerte. Andelen påviste rester over gjeldende grenseverdi er svært lav, og ingen av disse overskridelsene har til nå representert helsefare.