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.
2001
Sammendrag
Bruk av mjøldoggtolerante sorter er en av de mulighetene vi har til å hindre de stadig økende problemer med mjøldogg i agurk. Fem nye mjøldoggtolerante sorter ble vurdert i forhold til målesorten `Indira` i et høsthold med nedsenking og bruk av kunstig lys. Det viste seg at de nye sortene ikke nødvendigvis er noe bedre alternativ enn de vi til vanlig bruker.
Sammendrag
I prosjektet "Økt produktivitet i agurk og tomat gjennom miljøvennlig plantevern og effektiv dyrkingsteknikk" har en i perioden 1997-1999 arbeidet med ulike teknikker for rensing av resirkulerende næringsløsning i veksthus
Forfattere
Michel VerheulSammendrag
Som en del av prosjektet - Produktivitets- og kvalitetsøkning i agurk og tomat" ble vannforbruk og avrenning registrert i ulike gartnerier. Resultatene viste at gartnerne har blitt mer oppmerksommme på vanningen. Tomatgartneriene som var med i prosjektet har klart å redusere avrenningen til 20 prosent
Forfattere
Michel VerheulSammendrag
Praksis har vist at riktig vanning kan være svart så vanskelig. I et forsøk på å gjøre vanningen bedre er det gjennomført en registrering av plantenes daglig vannforbruk og på bakgrunn av dette utviklet enklet regler for vanntilførsel. Arbeidet er gjennomført av Planteforsk Særheim forskingssenter.
Forfattere
Christian UhligSammendrag
The aim of this study was to analyze the impact of airborne heavy metal pollution on Empetrum nigrum and Vaccinium myrtillus. Towards this end, tissue elemental composition and tissue frost hardiness of E. nigrum and V. myrtillus were investigated in response to long-term heavy metal pollution in the vicinities of nickel and copper smelters in Harjavalta (Finland), Nikel and Monchegorsk (Russia). Furthermore, heavy metal induced ecophysiological responses as changes in chlorophyll concentration, ABA content, water potential, organic acids, dark respiration, and maximum photosynthesis were studied for E. nigrum in situ and in greenhouse experiments. In addition, soil samples were taken from the vicinity of Nikel and Harjavalta and analyzed for total and plant available concentrations of Cu and Ni. Aerial Cu and Ni pollution were found to have caused increased concentrations of Cu and Ni in above ground tissues of V. myrtillus and E. nigrum. There was clear evidence that both species have taken up these metals at least partly from the soil. In general, V. myrtillus accumulated heavy metals to a lesser extent than E. nigrum. The highest concentrations of Cu and Ni in V. myrtillus generally did not exceed 100 mg/kg dw, even when growing in highly contaminated environments. This level is therefore suggested to be the upper limit of tolerance for V. myrtillus. The relatively low concentrations of Cu and Ni found in the species suggest that V. myrtillus avoids the uptake of these elements to a significant degree. In marked contrast, E. nigrum strongly accumulated Cu and Ni, and was proposed to be a hyperaccumulator for these elements. Since hyperaccumulation of heavy metals requires an effective detoxification mechanism, E. nigrum is assumed to be a highly Cu and Ni tolerant species. In general, tissues of E. nigrum showed increasing accumulation of heavy metals with increasing age. Stems and dead plant material showed particularly high concentrations of these metals. Remarkably high concentrations of Fe (225,000 mg/kg dw) and Cu (50,000 mg/kg dw) were found in the humus layer (Oh) below the canopies of E. nigrum. Airborne heavy metal pollution affected nutrient levels of above ground tissues of the two plant species studied in different ways. In V. myrtillus, S increased in proportion to Ni and Cu, while levels of Mn decreased. In E. nigrum, Fe increased in proportion to Ni and Cu, while levels of Ca decreased. In both species, different tissues exhibited different degrees of frost hardiness (LT50). The order of hardiness of specific tissues in V. myrtillus was: flower buds < vegetative buds < vascular tissue < cortical tissue < epidermal tissue, while those of E. nigrum were: flower buds < winter buds < two-year-old vascular tissue < one-year-old vascular tissue < two-year-old leaves < one-year-old leaves. Visual observations of V. myrtillus and E. nigrum indicated that shoot survival depended on the hardiness of the vascular tissue, which, in mid-winter, was generally hardy to between -30 °C to -35 °C for both species. Heavy metal accumulation in the overwintering shoots of V. myrtillus and E. nigrum had little or no effect on their frost hardiness. Decreased contents of chlorophyll pigments and organic acids and increased ABA contents near to the pollution source at Harjavalta indicate that heavy metal pollution has a negative effects on the physiological activity of E. nigrum. The results of this study suggest three major conclusions: 1) V. myrtillus is a moderately Cu and Ni tolerant species, which can survive at severely metal polluted sites by virtue of avoidance mechanisms; 2) E. nigrum is a highly Cu and Ni tolerant species that may survive at severely metal polluted sites due to a combination of tolerance and avoidance mechanisms.
Forfattere
Christian Uhlig Tore Sveistrup Ivar SchjelderupSammendrag
SammendragI løpet av de siste 30 år er det i flere undersøkelser dokumentert at reinsdyrbeiting påvirker vegetasjonen på Finnmarksvidda. Det er kjent at jordegenskapene har avgjørende innvirkning på planteveksten og følgelig på produktiviteten i hele økosystemet. Likevel er det gjennomført få undersøkelser på hvordan reinsdyrbeiting påvirker jordegenskaper og hvordan endringene i disse påvirker veksten. Målet med denne undersøkelsen var å dokumentere eventuelle endringer i fysiske og kjemiske jordegenskaper som følge av beite og tråkk fra rein. På fire lokaliteter på Finnmarksvidda ble det valgt ut 3 prøvesteder etter en subjektiv vurdering av tilstanden for lav og planter: A) godt lav- og plantedekk; B) redusert lavdekke, men moderat dekning av planter; C) lav og andre planter nesten helt borte. Det ble antatt at forskjellene i lav og annen plantebestand var forårsaket av ulik beiteintensitet. De undersøkte vegetasjonstypene var lavrik fjellbjørkeskog og lav-lynghei. På hvert prøvetakingssted ble jordmonnet beskrevet og prøve tatt sjiktvis for fysiske og kjemiske jordanalyser. Fysiske parametere det ble analysert for var jordtetthet, porevolum, vann- og luftinnhold ved forskjellige sug, plantetilgjengelig vann og tekstur. Kjemiske parametere det ble analysert for var pH, organisk karbon (org.-C), Kjeldahl-N, kationbyttekapasitet (CEC), basemetning og plantetilgjengelig P, Ca, Mg og K. Resultatene viste at mineraljorda besto av siltig mellomsand med 1-3% leir. På prøvesteder med god lavvegetasjon var det organiske laget cirka 6 cm. Planterøtter var i hovedsak lokalisert til det organiske toppsjiktet, men en god del røtter var også i de øverste 20 cm av mineraljorda. Tykkelsen på det organiske toppsjiktet avtok med avtakende tykkelse på lav- og plantedekke. Bare små forandringer i jordfysiske egenskaper ble funnet mellom de ulike prøvesteder. Det ble imidlertid funnet en sterk korrelasjon mellom org.C i jorda og CEC for alle prøvesteder og sjikt. Videre hadde det organiske toppsjiktet høyest innhold av plantetilgjengelig P, Ca, Mg og K. Ved å gå ut fra at forskjellene i lav og annen vegetasjon er et resultat av ulik beiteintensitet, tilsier resultatene at reinsdyrbeitingen kan føre til en betydelig reduksjon av det organiske materialet og dermed også av plantenæringsstoffer. På de undersøkte lokalitetene på Finnmarksvidda må mengden organisk materiale i jorda betraktes som en av nøkkelfaktorene for jordfruktbarhet og dermed også økosystemets bæreevne og produktivitet.
Forfattere
Christian Uhlig S Monni O JunttilaSammendrag
Empetrum nigrum L. (crowberry) is one of the plants surviving near the Cu-Ni smelters in Finland and Russia. According to field observations, the roots of E. nigrum are situating below 40 cm depth and the root biomass is reduced in the polluted sites. This could cause a reduced root uptake of macronutrients and trace elements in the field, and therefore, the possible element uptake by aboveground parts of E. nigrum was studied in a greenhouse. Six different treatment solutions containing various heavy metal and macronutrient concentrations were applied to the stems and leaves of E. nigrum and the chemical composition and ecophysiological parameters were measured. Heavy metal concentrations in the leaves and stem bark, and Cu concentrations in the stems, increased with increasing metal concentrations in the spraying solutions. The bark and leaves had higher heavy metal concentrations than the stems of comparable age classes. The macronutrient and Mn concentrations in E. nigrum did not change significantly with increasing element concentrations in the spraying solution. Neither the stem water potential nor the leaf chlorophyll concentrations showed any clear response to element applications. Therefore, the element uptake by aboveground parts of E. nigrum was not confirmed by this study. However, there was a tendency to a decrease in CO2 exchange rate and increase in foliar ABA content in plants treated with the highest element concentrations
Forfattere
Christian Uhlig T Eldhuset M Christoph R HornSammendrag
Winter damage of meadows is a serious problem for agriculture in Norway. Unfavorable physical conditions for plant survival include freezing, desiccation, and ice/ water cover. Excess of soil water, particularly in winter and spring, is regarded as one of the most important factors causing heavy yield reduction and poor persistence. One of the major causes for the occurrence of seasonally waterlogged conditions in northern ecosystems is the development of a continuous frozen layer during the period of annual frost in the winter. During spring melting periods, the annual frost table gradually disappears and causes water from melting snow and thawing soil to accumulate in overlaying soil layers. Once the annual frost has dissipated, well-drained conditions may prevail. The present study investigated seasonal changes in soil redox potential and soil water chemistry at one cultivated and one non-cultivated site at Alta, Northern Norway. Soils at both sites were considered being comparable except for the present vegetation and land-use. The vegetation of the non-cultivated site, which was also the previous vegetation of the whole area before its cultivation started in 1930`s, was dominated by birches (Betula pubescens), while timothy (Phleum pratense) and smooth meadow-grass (Poa pratensis) dominated the cultivated site. At both sites platinum redox electrodes were permanently installed at 5, 10 and 25 cm depth. Furthermore, soil water samples were gained from permanently installed suction lysimeters from 5, 15 and 40 cm depth and analyzed for Fe. Redox potentials were generally lowest during spring thaw in May and June at both sites. At 5 cm depth redox potentials below +330 mV, the theoretical boarder line for the existence of oxygen in soils, prevailed until the second week of June, thus about one month after the disappearance of the snow cover. During this period Fe soil water concentrations at 5 cm depth increased from 0.5 to about 1.5 mg/l at the non-cultivated site, and from 0.5 to 4.5 mg/l in the cultivated soil. Results indicate that seasonally waterlogged conditions in northern ecosystems can cause unfavorable conditions for root growth, and thus might reduce the length of the potential growing season
Forfattere
Christian Uhlig O JunttilaSammendrag
Uptake of Al, Cu, Fe, Mn, Ni, Ca, K, Mg, P, and S in Empetrum hermaphroditum ssp. hermaphroditum Hagerup and Vaccinium myrtillus L. from Ni, Cu and SO2 contaminated sites in Sør-Varanger, Northern Norway, were investigated. The primary objective was to study the effect of airborne heavy metal pollution on foliar element composition of these two dwarf shrubs. Ni distribution and availability in soils clearly indicate atmospheric deposition of Ni particulates in Sør-Varanger. Foliar Ni concentrations in E. hermaphroditum and V. myrtillus increased in relation to plant available Ni in corresponding soils. Leaves of E. hermaphroditum generally contained higher concentrations of Ni than leaves of V. myrtillus. Emissions influenced some features of leaf elemental composition of the two species in very different ways. In leaves of V. myrtillus, S increased in proportion to Ni and Cu, while levels of Mn decreased. In leaves of E. hermaphroditum, Fe increased in proportion to Ni and Cu, while levels of Ca decreased
Forfattere
Christian UhligSammendrag
Heavy-metal polluted forest ecosystems near industrial complexes are often characterised by sparse or non-existing understorey vegetation. This enhances the erosion of metal-contaminated particles by the wind, decreases the water-holding capacity of the soil, and facilitates the leaching of heavy metals into the ground water. However, some dwarf shrub species, e.g. Arctostaphylos uva-ursi and Empetrum nigrum, have been found to survive in contaminated soil in the vicinity of smelter areas. In this study we evaluate the copper resistance of these two species by comparing the results of revegetation experiment in the field to those of controlled greenhouse exposure experiments.