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.
2017
Forfattere
Caroline Brophy John A. Finn Andreas Lüscher Matthias Suter Laura Kirwan Maria-Teresa Sebastià Áslaug Helgadóttir Ole Hans Baadshaug Gilles Bélanger Alistair Black Rosemary P. Collins Jure Čop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Michael Fothergill Bodil E. Frankow-Lindberg An Ghesquiere Barbara Golinska Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Päivi Kurki Rosa Llurba Tor Lunnan Claudio Porqueddu Ulrich Thumm John ConnollySammendrag
1. Increased species diversity promotes ecosystem function; however, the dynamics of multi-speciesgrassland systems over time and their role in sustaining higher yields generated by increased diver-sity are still poorly understood. We investigated the development of species’ relative abundances ingrassland mixtures over 3 years to identify drivers of diversity change and their links to yield diver-sity effects.2. A continental-scale field experiment was conducted at 31 sites using 11 different four-speci esmixtures each sown at two seed abundances. The four species consisted of two grasses and two legumes, of which one was fast establishing and the other temporally persistent. We modelledthe dynamics of the four-species mixtures, and tested associations with diversity effects on yield.3. We found that species’ dynamics were primarily driven by differences in the relative growth rates(RGRs) of competing species, and secondarily by density dependence and climate. The temporallypersistent grass species typically had the highest RGRs and hence became dominant over time. Den-sity dependence sometimes induced stabilising processes on the dominant species and inhibitedshifts to monoculture. Legumes persisted at most sites at low or medium abundances and persistencewas improved at sites with higher annual minimum temperature.4. Significant diver sity effects were present at the majority of sites in all years and the strength ofdiversity effects was improved with higher legume abundance in the previous year. Observed diver-sity effects, when legumes had declined, may be due to (i) important effects of legumes even at lowabundance, (ii) interaction between the two grass species or (iii) a store of N because of previouspresence of legumes.5. Synthesis. Alongside major compositional changes driven by RGR differences , diversity effectswere observed at most sites, albeit at reduced strength as legumes declined. This evidence stronglysupports the sowing of multi-species mixtures that include legumes over the long-standing practiceof sowing grass monocultures. Careful and strategic selection of the identity of the species used inmixtures is suggested to facilitate the maintenance of species diversity and especially persistence oflegumes over tim e, and to preser ve the strength of yield increases associated with diversity.
Forfattere
John Connolly Maria-Teresa Sebastià Laura Kirwan John Anthony Finn Rosa Llurba Matthias Suter Rosemary P. Collins Claudio Porqueddu Áslaug Helgadóttir Ole Hans Baadshaug Gilles Bélanger Alistair Black Caroline Brophy Jure Čop Sigridur Dalmannsdottir Delgado Ignacio Anjo Elgersma Michael Fothergill Bodil E. Frankow-Lindberg Ghesquiere An Piotr Golinski Philippe Grieu Gustavsson Anne-Maj Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Tor Lunnan Paivi Nykanen-Kurki Angela Ribas Friedhelm Taube Ulrich Thumm Alex De Vliegher Andreas LüscherSammendrag
1. Grassland diversity can support sustainable intensification of grassland production through increased yields, reduced inputs and limited weed invasion. We report the effects of diversity on weed suppression from 3 years of a 31-site continental-scale field experiment. 2. At each site, 15 grassland communities comprising four monocultures and 11 four-species mixtures based on a wide range of species' proportions were sown at two densities and managed by cutting. Forage species were selected according to two crossed functional traits, “method of nitrogen acquisition” and “pattern of temporal development”. 3. Across sites, years and sown densities, annual weed biomass in mixtures and monocultures was 0.5 and 2.0 t DM ha−1 (7% and 33% of total biomass respectively). Over 95% of mixtures had weed biomass lower than the average of monocultures, and in two-thirds of cases, lower than in the most suppressive monoculture (transgressive suppression). Suppression was significantly transgressive for 58% of site-years. Transgressive suppression by mixtures was maintained across years, independent of site productivity. 4. Based on models, average weed biomass in mixture over the whole experiment was 52% less (95% confidence interval: 30%–75%) than in the most suppressive monoculture. Transgressive suppression of weed biomass was significant at each year across all mixtures and for each mixture. 5. Weed biomass was consistently low across all mixtures and years and was in some cases significantly but not largely different from that in the equiproportional mixture. The average variability (standard deviation) of annual weed biomass within a site was much lower for mixtures (0.42) than for monocultures (1.77). 6. Synthesis and applications. Weed invasion can be diminished through a combination of forage species selected for complementarity and persistence traits in systems designed to reduce reliance on fertiliser nitrogen. In this study, effects of diversity on weed suppression were consistently strong across mixtures varying widely in species' proportions and over time. The level of weed biomass did not vary greatly across mixtures varying widely in proportions of sown species. These diversity benefits in intensively managed grasslands are relevant for the sustainable intensification of agriculture and, importantly, are achievable through practical farm-scale actions.
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I Norge er det betydelige variasjoner i vær og klima mellom og innen ulike landsdeler. Temperaturene er høyere sammenliknet med andre områder på samme breddegrader på grunn av gunstige luft- og havstrømmer. Forholdene for kornproduksjon er likevel marginale, siden vekstsesongen er kort og relativt våt, noe som fører til et relativt lavt avlingsnivå. I følge klimamodellene er Norge blant de få områdene i Europa der en forventer en positiv effekt av klimaendringer på planteproduksjonen, men økt nedbør og mer ekstremvær er utfordringer som må håndteres.
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Feltforsøk og feltforsøksbasert forskning er et svært viktig element i NIBIOs faglige og vitenskapelige profil. Feltforsøk betyr også mye for instituttets økonomi. 11 avdelinger bruker i større eller mindre grad feltforsøk som verktøy i sin FoU-aktivitet. Disse avdelingene har en bruttoomsetning på om lag 300 mill. kr, og dekker sentrale forskningsfelt innen agronomi, jord- og plantefag, miljø og nyskaping. Feltforsøksvirksomheten er helt avgjørende for NIBIOs tilstedeværelse rundt omkring i landet og er fundamentet i aktiviteten ved instituttets forskningsstasjoner. Feltforsøk og feltbasert FoU krever betydelige ressurser; høy kompetanse innen en rekke fagfelt for forskere og forskningsteknikere, gode feltareal, et bredt spekter av ordinære landbruksmaskiner og spesielt forsøksteknisk utstyr, og omfattende fastliggende infrastruktur. NIBIO står foran betydelige utfordringer for å opprettholde kvaliteten og videreutvikle denne virksomheten........
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I flere tusen år har vi mennesker høstet av naturens ressurser, og slik har vi bidratt til å forme landskapet. Mye av naturen rundt oss er derfor ikke bare påvirket av vår tilstedeværelse, men direkte formet av langvarig og systematisk bruk. Dette er utgangspunktet for det vi i dag kjenner som kulturlandskapet.
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