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
Forfattere
Thomas Holm CarlsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Thomas Holm CarlsenSammendrag
Det er ikke registrert sammendrag
Sammendrag
To stabilize organic cereal production systems it is necessary to control Canadian thistle (Cirsium arvense) and other perennial weed species. The aim of the two presented experiments (I and II) has been to evaluate the effects of mechanical treatment in spring combined with competition from a one season cover crop. In both experiments we used the same mixture of cover crops; phacelia (Phacelia tanacetifolia Benth.), common vetch (Vicia sativa L.), red clover (Trifolium pratense L.) and Italian ryegrass (Lolium multiflorum Lam.). The first experiment (I) was arranged in a complete factorial split-plot design. In this experiment different root burial depths and root lengths of C. arvense simulated different mechanical treatments. Use of cover crop was the single factor that most effectively reduced the gain of biomass of C. arvense. At the final harvest combined treatment of deep root burial (15 cm), short root length (5 cm) and cover crop reduced number of new shoots of C. arvense by 95% and root biomass by 97% compared to shallow burial and no cover crop. At minimum regenerative capacity of C. arvense the number of leaves were 2 to 6 for the treatment with cover crop and 4 to 8 for the treatment without cover crop. In the second experiment (II), which had a complete factorial design, ± ploughing in autumn was combined with different fallow strategies in spring before sowing the cover crop. The disc harrowing during the fallow period was performed either 2x when fallow lasted for 3 weeks, or 4x when fallow lasted for 6 weeks. Additionally, all combinations of ± ploughing in autumn and length of the fallow period were combined with ± ploughing before sowing the cover crop (all together 8 treatments). In two additional subplots shallow ploughing preceded the autumn ploughing treatment (± ploughing). Preliminary results from experiment II confirms in general the conclusions from experiment I. Combining soil tillage and competition from a fast growing cover crop have potential for retarding perennial weeds. The classical approach for controlling couch grass (Elymus repens) was confirmed in this experiment, the longer soil tillage period the better weed control, and the soil tillage period should be proceeded by a deep ploughing. Ploughing in the autumn gave no additional effect on couch grass. Best control of Canadian thistle was obtained when only shallow ploughing was performed in the autumn, followed by a 6 week soil tillage period (3 weeks was not tested here) in spring and early summer and completed by ploughing before sowing the green manure cover crop. In conclusion, the experiments showed that intensive soil tillage combined with competition from a cover crop gave promising results for weed control. Due to the positive effect of moderate tillage operations attention to factors as nutrient supply, soil structure and energy use may still be ensured while a satisfying weed control is obtained.
Forfattere
Kjell Mangerud Lars Olav Brandsæter Kjell WærnhusSammendrag
The objective of the ongoing study is to obtain new knowledge to provide a fundament for improving weed harrowing in organic cereal production as well as optimising weed harrowing as an alternative for herbicides in conventional farming. Results from field experiments on three locations during three years will be presented and discussed. The experiments included the factors: a) different manufactures of spring tine weed harrows, type of tines and used with different aggressiveness (adjusted through tine working depth and speed); b) cereal developmental stages; and c) soil types (locations) and conditions as well as weed infestation levels. The project included new experimental equipment including a specially constructed 1.5 meter wide harrow, which made it possible to treat many small sub-plots. Cereal yield and quality, number and dry matter weight (biomass) of weeds, and soil water content, soil share strength, and soil penetration resistance were recorded. The resulting intensity of the harrowing operation was measured using digital pictures taken before and after harrowing to give an estimate of cereal coverage of the soil. Pre-emergence harrowing and harrowing at early 1-leaf crop stage reduced in general weed number and biomass compared to untreated control. The mean weed reduction over locations and years was about 40%, but this reduction was not always significant different to control plots. In one year, harrowing at those early stages gave an increase in weed number and biomass, presumably because of rainy weather after harrowing. In general, pre-emergence harrowing and harrowing at early 1-leaf stage increased crop yield compared to untreated, but harrowing at such stages occasionally also resulted in small yield reductions. We conclude, however, that this early harrowing should be carried out every year. Weed harrowing once, either at 2 or 3-4 crop leaf stages, also gave decreased weed number and biomass, but no clear influence on cereal yield. Therefore, harrowing at these late stages is an opportunity, if weather conditions do not allow weed harrowing at earlier stages. The combination of pre-emergence harrowing and harrowing at 3-4 leaf stage gave a significant reduction of weed number and biomass compared to untreated control. In general, harrowing twice gave increased crop yields, but the differences were only significant at one of the locations. The potential benefit of a second harrowing at the 3-4 leaf stage depends on the weed situation, number and biomass, as well as crop competitiveness. Our results have indicated that the threshold for weed harrowing may be around 300 annual weeds m-2, but more knowledge is needed for verifying the level of total number and species. If the number of weeds is less, weed harrowing twice gives a significant reduction in weed number, but not an increase in yield compared to only one weed harrowing at an early growth stage. Furthermore, our results indicate that the different types of harrows and tines will not work properly on all soil types. On light soils, all of them gave satisfying results. However, a normal tine (" 7mm bent Einböck or a " 10mm long straight CMN) is not rigid enough on soil types that build a soil crust after rain. An " 8mm bend Einböck tine, however, was better at breaking a soil crust and thereby improve cereal plant emergence on such soils. On the other hand, it is important not to adjust such tines too aggressive when no crust is present. Another trial showed that a straight tine will pick up less stones on stony soils than a bent one will do, stones which might damage the combiner during combining. Our results from one of the locations (medium light soil with stones) showed that yield as well as reductions in weed number or biomass m-2 was not affected by tine type.
Forfattere
Helge SjursenSammendrag
Frøugrasfrøbanken: * "Forteller" noe om driften. * Forhindre frøsetting mest mulig, både i selve grønnsakkulturen og i "saneringskulturen" * Alltid en balansegang mellom ugrasutviklingen og kostnadene ved ugraskontrollen Rotugras: * Rotugrasfrøbank utgjør bare 2-3% av total frøbank * Rotugraset bør bekjempes mest mulig i "saneringskulturen
Forfattere
Paul Hatcher Lars Olav Brandsæter G. Davies A. Luscher HL Hinz R. Eschen U. SchaffnerSammendrag
The increasing problems caused by Rumex (especially R. obtusifolius L., R. crispus L., and R. longifolius DC.) infestation to organic agriculture in Great Britain, Norway and Switzerland are discussed. Here, inadequate, costly or time-consuming non-chemical control options for Rumex are one of the major barriers for farmers converting to organic production. Potential biological control agents for Rumex in Europe are discussed. We conclude that the chrysomelid beetle Gastrophysa viridula Degeer and the rust fungus Uromyces rumicis (Schum.) Wint. remain the most promising of the researched indigenous species, and that G. viridula can be combined with non-chemical control methods. However, there is a need for biocontrol agents that target Rumex roots; several sesiid moth species are present in Europe which feed upon these, and we suggest that one, Pyropteron chrysidiformis (Esper), has good potential for Rumex biocontrol and merits further study within Europe.
Sammendrag
Forskningsresultater innenfor forebyggende og direkte tiltak for kontroll av rotugras i økologisk korndyrking ble gjennomgått. I løpet av kort tid vil det bli etablert en "link" til PDF filer med presentasjonene fra møtet i Rygge 27. novemer 2007.
Forfattere
Jan NetlandSammendrag
Fleire viktige ugrasmiddel i gønsaker blir borte fra marknaden om eit år. Det er lite nye middel prøving, men i krossblomstra kulturer og i gulerot blir Command og Boxer klomazon prøvd ut.
Forfattere
Espen GovasmarkSammendrag
Omhandler essensielle næringsstoffer med spesiell fokus på essensielle mikromineraler til planter og husdyr (jern, sink, mangan, kopper, molybden, kobolt, selen). Temaer som ble omtalt var status i dag, mulige problemer pga mikromineralmangel og mulige løsninger på prblemene.
Forfattere
Espen GovasmarkSammendrag
Besvarer spørsmålet "Kan biorest og kompost av matavfall brukes i økologisk landbruk?", og svaret er JA, men de må oppfylle spesifikke krav mhp kvalitet og produksjonsmåte.