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.
2007
Sammendrag
Nyttesoppen Neozygites floridana er en viktig naturlig fiende til veksthusspinnmidd. Plantevernmidler, spesielt soppmidler kan hemme denne nyttesoppen. Dette bør det tas hensyn til når en sprøyter mot soppsykdommer i jordbær og i andre kulturer der denne spinnmidden err et problematisk skadedyr.
Forfattere
Trygve S. Aamlid Lars Tørres HavstadSammendrag
Tiller demography and contribution to seed yield were studied in first year seed crops of smooth bromegrass (SB, Bromus inermis `Løfar") and meadow fescue (MF, Festuca pratensis `Salten") planted on different dates and with increasing plant densities (A: 15 Jun. / 11 plants m-2, B: 15 or 30 July / 44 plants m-2, C: 15 August or 10 September /178 plants m-2) in field trials at Landvik, SE Norway. While the total tiller population in most crops increased until seed harvest, it decreased during panicle elongation in crops of SB and MF that had reached 2000 and 3500 tillers m-2 in early spring, respectively. Except for the fact that many of the primary tillers of SB died after producing barren stems, tillers formed in August and September had the greatest chance of becoming reproductive and produced the heaviest inflorescences in both species. Most tillers produced in winter or early spring either remained vegetative or died, but spring-emerging tillers contributed up to 30% of the total seed yield in early-established, low-density crops of MF. It is concluded that spring-emerged tillers contribute more to seed yield in MF than in SB and more in seed crops established early at low plant density than in crops established late at higher density.
Forfattere
Svein Ø. Solberg Kari Bysveen Trygve S. AamlidSammendrag
Subterranean clover (Trifolium subterraneum) as a companion crop during establishment of organic timothy (Phleum pratense) seed crops was examined in four field trials studies in SE Norway from 2001 to 2004. Clover and timothy were either mixed before sowing or seeded in every other row with the possibility of removing winter-surviving plants of clover in the spring of ley year 1. Trifolium alexandrinum, T. resupinatum, T. incarnatum, Melilotus officinalis, Lotus corniculatus and Melicago lupulina were also included in the study, in addition to control plots with no legume companion crop. No manure was applied except to the spring wheat cover crop in the year of establishment. The results showed that subterranean clover was the most promising legume, resulting in a 20 % increase in timothy seed yield in the first seed harvest year. The result could partly be explained by less competition from weeds during the establishment of the seed crop. In autumn of the sowing year, after the wheat had been harvested, subterranean clover covered up to 70 % of the soil surface, leaving less space for weeds. During the following winter, subterranean clover died, leaving more space to the first year timothy seed crop. The positive results with subterranean clover as a companion crop were confirmed by on-farm studies at three different sites. A seed mixture of 0.5-0.7 kg ha-1 timothy and 1.0-1.2 kg ha-1 subterranean clover is now recommended when establishing organic timothy seed crops on farms with no or limited access to manure.
Forfattere
Kari Bysveen Trygve S. Aamlid Svein Ø. SolbergSammendrag
During 2002-2005, Norwegian seed yields of meadow fescue (Festuca pratensis Huds.) were 52% lower in organic than in conventional seed production. The difference was most conspicuous in ley year 1, suggesting that seed crop establishment is a limiting factor in organic seed production. Meadow fescue is usually underseeded in a cover crop of spring wheat or spring barley, and many organic growers delay the underseeding until after harrowing for weed control. Our objectives were (1) to determine whether organic seed crops of meadow fescue should be underseeded in the same operation as, or immediately after, the cover crop (implying no harrowing for weed control); or if they should be underseeded in conjunction with, or just after, weed harrowing (on average nine days after the cover crop); and (2) to compare the establishment of meadow fescue seed crops without cover crop or in cover crops of spring barley, spring wheat, peas or green fodder (barley + peas). On average for all cover crops and four trials, first year"s seed yields of meadow fescue were 11 % lower for crops seeded after weed harrowing than for crop seeded immediately after the cover crop. Weed harrowing combined with delayed seeding also resulted in more scentless mayweed (Tripleurospérmum inodórum) and other weeds in ley year 1. Despite less plant-available nitrogen in spring, seed crops underseeded just after the cover crop were more lodged than crops underseeded after weed harrowing. On average for the two seeding dates, the highest seed yield were produced from crops seeded in pure stand and from crops that had been underseeded in green fodder and received an extra 30 kg N ha-1 in manure shortly after green fodder harvest in late July. The results suggest that seed crops of meadow fescue need ample supply of light, water and nutrients in August to produce a good seed yield in ley year 1.
Forfattere
Jon Atle Repstad Trygve S. Aamlid Lars Tørres HavstadSammendrag
Norwegian agriculture is totally dependent on a safe supply of seed of winter-hardy timothy varieties. The annual seed consumption varies depending on the extent of winter damages, particularly in northern Norway, and the average seed yield varies with weather and harvest conditions in the seed-producing districts in the southeastern and central part of the country. To buffer these variations, seed companies always keep stocks corresponding to 50-100 % of the average annual seed consumption. Such large stocks are risky to maintain as seed lots will loose germination over time. Our objective was to elucidate the effect of seed harvest time and seed storage location on the longevity of timothy seed. In 2003, timothy `Grindstad" was combined directly on 2, 5 or 8 August corresponding to a seed moisture content (SMC) of 34, 27 and 20 %, respectively. After harvest the seed was dried to 10-11 % SMC. Germination analyses were accomplished 3, 15, 26 and 38 months after seed harvest; the three latter after splitting each seed lot into four sub-lots that were stored either in a conditioned seed store (4ºC, 30% RH), or in unconditioned warehouses at there climatically different locations. While seed harvest time had no effect on germination three months after harvest, differences became increasingly evident as time went by. After 38 months" storage, seed stored in the conditioned store or in the warehouse at the continental location Tynset germinated, on average for harvest times, 15-16 units better than seed stored in the warehouse at the coastal location Vaksdal; and seed lots harvested at 20 % SMC germinated, on average for storage locations, 24 units better than seed harvested at 37 % SMC. While it has long been documented that direct combining at high SMC may damage seed germination, there has been less awareness that this damage may not manifest itself until after a certain storage period.
Forfattere
John Ingar Øverland Trygve S. AamlidSammendrag
The application of plant growth regulators (PGRs) and insecticides, either alone or in tank mixture, was tested in nine on-farm trials laid out according to three different experimental plans in SE Norway (59-61ºN) from 2002 to 2006. The first plan compared the PGRs trinexapac-ethyl (125 or 250 g a.i. ha-1), chlormequat chloride (2000 g a.i. ha-1) and ethephon (240 g a.i. ha-1) applied on two dates and compared with an untreated check. On average for three trials, seed yield of the diploid cv. Nordi (origin 61ºN) increased 15 % by application of trinexapac-ethyl (250 g a.i. ha-1) at stem elongation, decreased 18 % by application of ethephone at flower bud emergence, and was not significantly affected by any of the other treatments. The diploid cv. Bjursele (two trials) and the tetraploid cv. Betty (one trial) showed no response to any of the PGRs. In the second experimental plan, laid out in two seed crops of the diploid cv. Lea in 2005, trinexapac-ethyl (125 or 250 g a.i. ha-1) was applied alone or in tank mixture with the insecticides alpha-cypermethrin (20 g a.i. ha-1) or dimethoate (500 g a.i. ha-1) on two dates. These trials verified the positive effect of trinexapac-ethyl, but the insecticides had no significant effect, which is not surprising as no harmful insects were detected. The third experimental plan compared insecticides at two developmental stages in a seed crop of cv. Lea with a high occurrence of Apion seed weevil and the lesser clover leaf weevil Hypera nigrirostris. In this trial, alpha-cypermethrin increased seed yield by 14 % when applied at flower bud emergence. Effective from 2004, Moddus 250 EC (trinexapac-ethyl) was approved in Norwegian seed production of selected cultivars of red clover. Research is still underway to evaluate the need for control of various weevils.
Forfattere
Trygve S. AamlidSammendrag
Foredraget gir en oversikt egenskapene til tunrapp, engrapp og engelsk raigras, de viktigste grasartene på norske fotballbaner
Forfattere
Trygve S. AamlidSammendrag
Foredraget gir en oversikt over de siste års forsøksresultater med ugrasbekjempelse ved frøavl av de tre artene.
Forfattere
Trygve S. AamlidSammendrag
De siste års viktigste forsøksresulater fra frøavl av kløver ble gjennomgått.
Forfattere
Trygve S. AamlidSammendrag
Foredraget gav en ovesikt over de siste års forsøksresultater med frøavl av timotei, engsvingel og rødkløver.