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.
2008
Sammendrag
Kvitkløver egnar seg godt i slåtteng også i Noreg. Samanlikna med raudkløvergraseng, gav kvitkløvergraseng like stor avling og same mjølkeproduksjon. Raudkløver i surfôret gav høgare innhald av fleirumetta feitt og mykje høgare innhald av planteøstrogen i mjølka enn kvitkløver.
Forfattere
Håvard SteinshamnSammendrag
Grassland legumes are essential in organic ruminant livestock production due to their ability to fix atmospheric nitrogen (N), providing high yields of high feeding value without N fertilization. White clover (Trifolium repens L.) and red clover (Trifolium pratense L.) are the most important legumes of temperate grasslands with white clover as the most widely used. New research has reviled new properties of red clover that may affect animal performance and product quality significantly. Red clover containing diets have increased the production of milk and meat (compared with grasses) and the content of beneficial fatty acids in milk and meat (compared with grasses and other legumes), improved the efficiency of feed N utilization (compared with Medicago sativa L.), and increased the milk content of isoflavones (compared with grass and white clover). Red clover contains high levels of the enzyme polyphenol oxidase that might reduce the extent of lipolysis and proteolysis. The paper presents a review on resent results from own and others" research on the use of red clover in the diet of ruminants and the likely mechanisms by which red clover affects production and product quality
Sammendrag
Red (RC) or white (WC) clover were grown in mixture with grasses, ensiled and offered to dairy cows in early lactation over two successive years (48 cows per year) to compare grassland yield, feed intake, milk production and milk quality. The crops were ensiled in round bales and proportional mixtures of the second and third cut prepared each year were used to ensure that the silage treatments were representative of the crop. In addition to silage type, concentrate supplementation, without and with (10 kg/day), was included as a factor in a 2 X 2 factorial, continuous experiment. Total dry matter (DM) yield, silage chemical composition and total DM intake was hardly affected by silage type. There was no effect of silage type on milk yield and milk constituents either, except for higher milk protein content (P < 0.05) on WC and higher milk fat content of C18:3n-3 (P < 0.001), C18:2n-6 (P < 0.05) fatty acids (FAs) and sum of polyunsaturated FA (P < 0.001) and lower n-6/n-3 FA ratio (P < 0.01) on RC. Concentrate supplementation increased total DM, N and net energy intakes (P < 0.001), milk yield (P < 0.001), milk fat (P < 0.01) and protein (P < 0.001) content, decreased the milk urea content (P < 0.001), and increased the milk fat content of short- and medium-chained FAs (< C16, P < 0.001), C18:0 (P < 0.01) and C18:2n-6 (P < 0.001), decreased the content of C16:0 (P < 0.05), C18:1t11 (P < 0.001) and C 18:3n-3 (P < 0.001), and increased then 6/n-3 FA ratio (P < 0.001). The effect of concentrate supplementation was not affected by silage type, except for milk protein content where the positive effect of supplementation was stronger on WC than on RC diets (P < 0.05). This study illustrates that the white- and red clover-grass mixtures investigated were widely similar with regard to their effects on grassland yield, silage intake and milk production and milk constituents, except for a higher milk fat content of C18:3n-3 and C18:2n-6 and lower n-6/n-3 FA ratio on red clover diets. Our findings also show that N conversion efficiency from feed to milk on pure forage diets is more sensitive to changes in dietary protein intake than silage diets containing cereal based concentrates. (C) 2008 Elsevier B.V. All rights reserved.
Forfattere
Martha Ebbesvik Sissel Hansen Anne Kjersti Bakken Turid Strøm Espen Govasmark Håvard SteinshamnSammendrag
Innholdet av råprotein i en stor del av graset fra førsteslåtten på økologiske ku- og sauegårder var lavt. Innholdet i andreslåtten var høyere. Kløverandelen i engavlinga forklarte en stor andel av variasjonen i proteininnholdet.
Sammendrag
Commercial strawberry production in Scandinavia started as early as the 1920s, with the cultivar `Abundance". Although the production area was about 1500 ha, the yield was very low (< 3 t ha-1). In the 1960s Scandinavia had a large increase in strawberry area and yield per hectare. The strong development of strawberry production came after the introduction of the cultivar `Senga Sengana", new growing techniques (black polyethylene mulch) and the release of new and more efficient fungi- and herbicides. Over the past 30 years, the yield and growing area has stabilized, although the number of strawberry growers has decreased strongly. Today, Scandinavia has a strawberry production of about 8500 ha, yielding about 75 000 tons of berries in a very short summer-season. Almost all strawberry growing is perennial production with single-cropping (SD) cultivars in open field, and the fields are normally kept for 3-5 years. The main strawberry cultivars grown today are `Korona", `Polka", `Honeoye", `Jonsok" and `Florence". The area of `Sonata" is increasing. While almost all strawberries up to the 1970s were picked and sold through a "pick-your-own" system, today, almost 95% is sold through wholesale dealers for fresh consumption, and only a small amount is frozen for processing. Since the mid 1990s, there has been a slow decrease in the strawberry production area in Scandinavia. This is due to an over-production of strawberries in a short, hectic season, giving very low prices. To avoid this, attempts are being made to extend the season, especially with row cover, plastic tunnels, stored plants and new cultivars (including everbearing cvs.). The growing area covered with polyethylene tunnels are now increasing in all the Scandinavian countries. The area of raspberry in Scandinavia was stable up to the 1990s, with a production of about 500 ha. The production was mainly for the processing industry with old Norwegian and Finnish cultivars. Since 1995, the raspberry area has doubled, and is still increasing. This came after introduction of the Scottish cultivar `Glen Ample", which has shifted the production from mainly for the processing industry, over to mainly for fresh consumption. This development was started in Norway, and the other Scandinavian countries are following up. Introduction of `Glen Ample" has given the growers new possibilities to increase their income, and the focus on extending the season and on berry quality, have increased. About half of the Norwegian raspberry production is now under polyethylene tunnels, and this leads again to new possibilities of extension of the season by growing long canes or primocane-fruiting varieties like `Polka". Less than 120 ha of blueberries are produced in Scandinavia. The yields are low, and the picking cost too high. But, there is increasing interest, related to health benefits, from the marked. The main challenges for berry production in Scandinavia are access to and cost of labour, and how to meet the increased competition from imported berries. The Scandinavian countries have also strong restrictions in the number, and use of pesticides. Increased focus on taste and quality will be important in the future.
Sammendrag
Environmental control of the annual growth cycle of 'Glen Ample' raspberry has been studied in order to facilitate crop manipulation for out-of-season production. Plants propagated from root buds were raised in long days (LD) at 21 degrees C and then exposed to different temperature and daylength conditions at varying ages. Shoot growth was monitored by weekly measurements and floral initiation by regular sampling and examination of axillary bud #5. Under natural summer daylight conditions at 60 degrees N shoot growth was nearly doubled at 21 degrees C compared with 15 degrees C, while at 9 degrees C one half of the plants ceased growing and formed flower buds at midsummer. Developing shoots have a juvenile phase and could not be induced to flower before the 15-leaf stage. No significant reduction in induction requirements was found in larger plants. Plants exposed to natural light conditions from 10th August, had an immediate growth suppression at 9 and 12 degrees C with complete cessation after 4 weeks (by September 7). This coincided with the first appearance of floral primordia. At 15 degrees C both growth cessation and floral initiation occurred 2 weeks later (by September 21), while at 18 degrees C continuous growth with no floral initiation was maintained until early November when the photoperiod had fallen below 9 h. The critical photoperiod for growth cessation and floral initiation at 15 degrees C was 15 h. Plants exposed to 10-h photoperiods at 9 degrees C for 2-4 weeks had a transient growth suppression followed by resumed growth under subsequent high temperature and LD conditions, while exposure for 5 or 6 weeks resulted in complete growth cessation and dormancy induction. The critical induction period for floral initiation was 3 weeks although no transitional changes were visible in the bud before week 4. When exposed to inductive conditions for marginal periods of 3 or 4 weeks, an increasing proportion of the plants (20% and 67%, respectively), behaved as primocane flowering cultivars with recurrent growth and terminal flowering. It is concluded that growth cessation and floral initiation in raspberry are jointly controlled by low temperature and short day conditions and coincide in time as parallel outputs from the same internal induction mechanism. (C) 2008 Elsevier B.V. All rights reserved.
Sammendrag
Etter sine dyrkingsmessige egenskaper blir våre dyrkete hagejordbær inndelt i engangsbærende og flergangsbærende (remonterende) sorter. Mens blomstringen hos de vanlige engangsbærende sortene har vært gjenstand for omfattende undersøkelser og er kjent for å være indusert av kort dag (KD), har det vært betydelig forvirring i litteraturen om daglengde-reaksjonen for de flergangsblomstrende sortene. I et nylig avslutta forskningsprosjekt har vi imidlertid kunnet fastslå at danningen av blomsterknopper hos disse sortene er indusert av langdags (LD)-forhold. Ved høy temperatur (> 25 ºC) er disse plantene obligatoriske LD-planter, mens de ved midlere temperaturer (15 - 20 ºC) også vil blomstre under KD-forhold, men da er blomstringen sterkt forsinket. Ved lave temperaturer (< 10 ºC) er imidlertid også disse sortene dagnøytrale i likhet med flere av de engangsbærende sortene.
Sammendrag
A field fertilizer trial planted in late August was used to study effects of fertilizer timing and application method on flowering and ripening in strawberry cv. Korona. In treatment 1 (T1), fertilization in August prior to planting was followed by fertigation with low nutrient rate from May to August in the first harvest year. In treatment 2 (T2) all nutrients were applied as nutrient solution from May to August the first harvest year. By August in the first harvest year, the total amount of fertilizer applied was similar for both treatments (80 kg N ha(-1)). Equal amounts of water were also applied in both treatments. In the second harvest year, all the fertilizer was applied using fertigation from May to August. Both treatments were given the same fertilizer rate (80 kg N ha(-1)) to study after-effects of T1 and T2. In the first harvest year, preplant fertilized plants flowered earlier and required a higher number of days and day-degrees from anthesis to berry ripening than did T2 plants which were not fertilized until spring the first harvest year. Significant differences were found in yield but not in the number of berries, as berry size was significantly higher in T1. No significant differences were found between fertilizer treatments in the second harvest year, although T2 tended to yield the maximum number of berries later in the season than T1.
Sammendrag
The environmental control of flowering in five populations of Fragaria virginiana ssp. glauca and three populations of F virginiana ssp. virginiana (henceforth referred to as F virginiana), obtained as seed from the National Plant Germplasm Repository, Corvallis, OR, USA, has been studied under controlled environment conditions. Except for the F virginiana ssp. glauca population PI 551648 from the Wasatch Mountains in Utah, which was truly day-neutral across a 9 degrees - 27 degrees C temperature range, all the other populations of both sub-species behaved as quantitative (facultative) short-day (SD) plants with earlier and more abundant flowering under SD than under long-day (LD) conditions. Flowering of the remaining F virginiana ssp. glauca populations was governed by a significant interaction of photoperiod and temperature. The SD dependence for flowering increased with increasing temperature from 9 degrees C to 27 degrees C. The optimum temperature for the SD flowering response was 15 degrees - 21 degrees C. While SD promotion of flowering was more pronounced in the F virginiana populations, temperature had no significant main effect on flowering in this sub-species, demonstrating a wide temperature tolerance for flowering. Vigorous runner formation was observed in all populations, in both SD and LD, with a highly significant advancement effect of increasing temperature. The flowering and runnering responses of these E virginiana populations are discussed in relation to their putative paternity of perpetual-flowering F. X ananassa cultivars. It is concluded that, with the complex inheritance in these octoploid plants, the flowering responses of the populations studied here are not reflected in the LD flowering response of cultivated everbearing strawberries.
Sammendrag
Det er en vanlig oppfatning blant dyrkere at relativt låg temperatur er gunstig for rik blomsterdanning hos jordbær. I ei tid med klimaendring, er det derfor mange som spør om hvordan de milde høstene vi har hatt i det siste, påvirker blomstring og avling. Samtidig er det mange som har erfart at en sein jordbærsort som "Florence" har gitt små avlinger i nord og i høgtliggende områder med tidlig og kjølig høst. Vi har derfor studert virkningen av ulike temperaturer på blomsterdanningen hos sortene "Florence", "Frida" og "Korona" under kontrollerte klimaforhold og jamført dette med avlingstall fra forsøk med de samme sortene i distrikt med ulike temperaturforhold. Resultata viser at optimal temperatur for kortdags-indusert blomsterdanning er så høg som 18 °C, og at sortsforskjeller i avling i ulike distrikt for en stor del kan forklares ut fra forskjeller i høst-temperaturen.