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.
1999
Forfattere
Steinar DraglandSammendrag
Det er ikke registrert sammendrag
Forfattere
Steinar DraglandSammendrag
Det er ikke registrert sammendrag
Forfattere
Hans StabbetorpSammendrag
Flere faktorer som har betydning for avlingsnivået blir analysert og omtalt. Avlingsnivået i Norge i forhold til utlandet, og framtiden for norsk korndyrking blir også diskutert.
Sammendrag
There is growing interest in production of arable crops on organic farms with few or no livestock. This calls for more detailed knowledge on how to optimize the fertilization effect from preceding crops. As part of a research programme started in 1998 we are studying to what extent undersown clover can supply successive grain crops with neccessary nutrients, in particular nitrogen (N). We are also examining if and how release of N can be manipulated, in order to synchronize it with the N demand. In this paper we discuss central hypotheses and present some preliminary results from experiments with undersown clover crops. Considerable amounts of N (50-90 kg ha -1) were found in above ground clover biomass in a field experiment with undersown clover. In a laboratory experiment, above ground biomass of clover and straw (harvested in autumn) was mixed into the soil in amounts proportional to the measured field yields. This resulted in an insignificant net N mineralization during the first 80 days. The reason was immobilization of N during straw decomposition. By day 160, however, considerable amounts of N were remineralized. In a following experiment, both above and below ground biomass of clover and straw (harvested in spring) was incubated. This resulted in net N mineralization from the start of the incubation. Probably, mineralization of straw C during winter had reduced the N immobilization potential. We hypothesize that the N effect of clover subcrops, in principle, can be improved by separating in time straw C mineralization from clover N mineralization. We also speculate that this can be implemented in farming practices. Moreover, roots were disregarded in the first experiment, but included in the second. In a third incubation experiment, with red clover, we found that root N contributed with 30% of mineralized N from the clover biomasss after 25 days. Thus, root-derived inorganic N may explain the differences between the two first experiments.When assessing the N effect of crop residues on successive plant growth, root N and root degradability must, therefore, be taken into consideration. In organic arable crop systems with small amounts of animal manure, microbial fixation of atmospheric N must be maximized and losses of N from the system must be minimized. This is the subject of further research in this programme.
Forfattere
Ragnar EltunSammendrag
In the Apelsvoll cropping system experiment, the productivity, environmental side-effects and farm economy of the following six cropping systems are investigated: conventional arable (CON-A), integrated arable (INT-A), ecological arable (ECO-A), conventional forage (CON-F), integrated forage (INT-F) and ecological forage (ECO-F). Each system, which have eight year rotations, is established on model farms of 0.2 ha each. Presented here are the yield results of the first crop rotation period. The average grain yields of barley in the systems INT-A, ECO-A, CON-F, INT-F and ECO-F were 85, 66, 95, 76 and 67%, respectively, of the CON-A system. Wheat grain yields showed an even greater yield reduction with ecological as compared to conventional cropping than barley, while a mixture of oats and peas gave higher yield than barley in ecological cropping. The grain protein content and grain size in ecologically grown wheat were lower than in conventionally grown wheat. Both for potatoes, root and forage crops, the yield reduction incurred by integrated and ecological cropping was smaller than for cereals, and it is concluded that, with regard to yields, a change from conventional to integrated or ecological cropping is easier to achieve in mixed farming systems with livestock than in arable farming systems without livestock. For cereals there tended to be a positive yield effect going from single (ARABLE) to mixed (FORAGE) cropping systems. Otherwise, the yield relations between individual crops and between cropping systems were fairly stable during this eight year cropping period, and it is postulated that, under most Norwegian conditions, the yields with integrated and ecological cropping will stabilise at a significantly lower level than the yields obtained formerly with conventional farming.
Forfattere
Ragnar EltunSammendrag
Resultata frå det første åtteårige omløpet i Dyrkingssystemprosjektet på Apelsvoll syner at intensive dyrking og einsretta korn- og husdyrproduksjon må ta mykje av skulda for dei miljøproblema ein har i landbruket. I eit miljøtilpassa landbruk må det leggast aukande vekt på vekstfølgjene i dyrkingssystema og deira betydning for t.d. næringstofftap, jordtap, jorda si kjemiske, fysiske og biologisk tilstand og behovet for kjemisk plantevern. Landbruksforskinga må konsentrere seg meir om verknaden av å leggje om til nye dyrkingssystem enn tilpassingar innanfor eksisterande system.
Forfattere
Lars Nesheim David BarlandSammendrag
Grøftevann fra feltlysimeteret på Kvithamar ble analysert for plantevernmidler ved fire uttak, fra juni til oktober. Bentazon ble påvist ved alle uttak, til tross for at dette stoffet ikke er brukt på feltet siden 1991. Ved to uttak i november ble det analysert for AMPA og glyfosat, og begge stoff ble funnet.
Forfattere
Gustav FystroSammendrag
Sluttrapport til Norges Forskningsråd for prosjektet "Tilpassa nitrogengjødsling i eng". Mineralisering av nitrogen er sentralt i prosjektet. Det er gjennomført felt- og laboratoreieforsøk. Rett generell gjødsling med nitrogen til eng, og justering av denne, er viktige mål.
Forfattere
Gustav Fystro Sigmund FjelltunSammendrag
Nærings- og partikkelavrenning frå nedslagsfeltet til Volbubekken er rapportert for 1997/98, og sammenlignet med tidligere år. Feltet er 1680 daa, og jordbruksareal utgjer ca. 40 %. Separate målingar for utmarksareal er rapportert. Jordbrukspraksis og klima er gjort greie for i rapporten.
Forfattere
Gustav FystroSammendrag
Kort presentasjon av prosjektet "Tilpasset nitrogengjødsling i eng