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.
2003
Forfattere
Erland Kjesbu Håvard MjeldeSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Forfattere
Erland Kjesbu Lill-Ann Gundersen Anne Moxnes JervellSammendrag
Det er ikke registrert sammendrag
Sammendrag
Wintering ability in the field and resistance to different winter-stress factors under controlled environmental conditions were studied in a full-sib family of perennial ryegrass (Lolium perenne L.). Significant variation in tolerance to freezing and ice encasement, resistance to pink snow mould (Microdochium nivale) and also in winter survival and spring growth were found between the different genotypes. No strong correlations were found between the resistances to the different stress factors. These results indicate that resistance to different winter-stress factors is controlled by separate genes in perennial ryegrass. A low but significant positive correlation was found between spring growth of plants in the field after the first winter and both freezing tolerance and M. nivale resistance measured in controlled environments. Cold hardening seemed to influence freezing tolerance and M. nivale resistance differently in the different genotypes, since no distinct correlation in tolerance to freezing or resistance to M. nivale was found between unhardened and hardened plants. Tolerance or resistance to most of the winter stress factors measured was positively correlated with plant size.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Gudbrand LienSammendrag
Stochastic budgeting is used to simulate the business and financial risk and the performance over a 6-year planning horizon on a Norwegian dairy farm. A major difficulty with stochastic whole-farm budgeting lies in identifying and measuring dependency relationships between stochastic variables. Some methods to account for these stochastic dependencies are illustrated. The financial feasibility of different investment and management strategies is evaluated. In contrast with earlier studies with stochastic farm budgeting, the option aspect is included in the analysis.
Sammendrag
A model is presented to investigate the optimal economic life cycle of grass leys with winter damage problems in northern Norway and to determine the threshold of winter damage before it is profitable to reseed. A two‐level hierarchic Markov process has been constructed using the MLHMP software (the MLHMP software and the plug‐in constructed for this model are available for download at http://www.prodstyr.ihh.kvl.dk/software/mlhmp.html). The model takes uncertainty concerning yield potential, damage estimation and weather‐dependent random fluctuations into account. A Kalman filter technique is used for updating the knowledge of yield potential and damage level. The application of the model is demonstrated using data from two commercial Norwegian farms. As parameter estimates vary considerably among farms, it is concluded that decision support concerning optimal economic life cycle of grass leys should be done at farm level. The results also show the importance of using a flexible dynamic replacement strategy. Use of the model for specific farm situations is illustrated.
Forfattere
Wenche E. DramstadSammendrag
Det er ikke registrert sammendrag
Forfattere
Birger Solberg Torjus BolkesjøSammendrag
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Sammendrag
Det ble lagt ut ni forsøksfelter i sjiktet granskog på Østlandet, i 400-600 meters høyde. Åtte av feltene lå på vegetasjonstypen blåbærgranskog. Effekten av hogstmetode (flate, gruppehogst, og skjermstillinger av forskjellig tetthet) og markberedningsmetode (flekkmarkberedning, inversmarkberedning og ingen markberedning) på etablering og vekst av naturlig foryngelse samt kulturplanter ble undersøkt. Begge markberedningsmetodene ga i hovedsak et godt resultat når det gjalt naturlig foryngelse. Det ble noen flere planter med flekk- enn med inversmarkberedning. Et godt frøår rett etter markberedningen bidro til den gode etableringen. Uten markberedning var planteetableringen imidlertid dårlig. Det var noe færre planter på hogstflata enn i de andre hogstbehandlingene. Plantenes vekst ble bedre med økende hogstintensitet. Etter seks vekstsesonger var kulturplantene 30-40 cm høyere enn naturforyngelsen.