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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

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Sammendrag

Stømner vannverk A/L har vannforsyning fra tre borebrønner i fjell. Fra sommeren 2007 produserte brønnene gradvis mindre vann. Denne rapporten er basert på generell geologisk informasjon og opplysninger fra involverte parter. Det er ikke gjort noen spesifikke undersøkelser for å avdekke årsakssammenhengen, og det er derfor umulig å fastslå entydig hva som har skjedd. Det mest sannsynlige er imidlertid at grunnvannstrykket i fjellet har sunket på grunn av aktivitet i et pukkverk som befinner seg ca. 900 m nord vest for fjellbrønnene. Trykkgradientene fra grunnvannet ved fjellbrønnene til pukkverket er imidlertid så små at grunnvannet ikke kan dreneres ut i pukkverket. Det er derfor mest sannsynlig en indirekte årsakssammenheng: Aktiviteten i pukkverket kan ha ført til mikro bevegelser i fjellsprekkene enten i den granittiske gneisen eller i kontaktsonene til grønnskiferen. Bergartsgrensen mellom grønnskiferen og den granittiske gneisen befinner seg anslagsvis 300 m rett sørvest for pukkverket. Mikrobevegelser i sprekkene kan i sin tur ha medført en senkning i grunnvannstrykket i området. Fordi det er relativt små vannmengder som produseres i brønnene, kan en liten endring i permeabiliteten gi store senkninger i grunnvannstrykket. Eventuelle lekasjer som kan ha oppstått fra grunnvannsmagasinet, vil være svært vanskelig å identifisere dels fordi vannmengdene er så beskjedne og dels fordi lekasjene mest sannsynlig vil finne sted i løsmassene. Hensikten med denne rapporten er å foreslå hvordan mulige årsakssammenhenger kan sannsynliggjøres.

Sammendrag

Det er foreslått plassering av grunnvannsbrønn til 6 boenheter dimensjonert for 42 personer. Det er foretatt en vurdering av potensielle forurensinger, inkludert flom, lokale avløpsrenseanlegg, hesteinnhegning, vegsalting, nedlagte deponier og generell aktivitet på eiendommen. Ingen av kildene vurderes å påvirke vannkvaliteten av grunnvannet negativt forutsatt visse forhåndsregler. Det anbefales boring i skråningen nordøst for boligene.

Sammendrag

The ability to predict the timing of optimum soil workability depends on knowledge of the extent and structure of variability in main physical characteristics of the soil. Our objectives were to quantify the variability in texture and carbon content within soil map units in a small agriculture-dominated catchment in South-east Norway and to assess implications of variability in texture and carbon content on land management operations, using the predicted maximum water content for optimum workability as an example. Information from three different sources were used: a soil map (1:5000), a large sample grid (100 m spacing, 270 ha extent), and a small sample grid (10 m spacing, 2.25 ha extent). Readily available information on texture and organic matter content from the soil map was found to be of limited use for soil management due to broad textural classes together with deviations from the mapped main textural classes. There were significant differences in clay, silt and sand content between the different soil textural classes on the soil map. Statistical distributions within soil map units were generally either positively or negatively skewed and the coefficient of variation was intermediate, 15-50%. Most of the variation in both grids was spatially correlated. The large grid was dominated by a patchy structure, whilst the small grid showed a systematic trend with a gradual transition indicating fuzzy boundaries between map units in this catchment. The effective range for texture was 16 times larger in the large grid. Implications of variability in texture and carbon content on land management operations were assessed for the maximum water content for optimum workability (Wopt), predicted using pedotransfer functions. Wopt was usually in the same range as the water content at-100 kPa matric potential, indicating that considerable evaporation in addition to drainage is required for obtaining workable conditions in the field. The time required for obtaining the water content was estimated to about 5 days, which is longer than an average length of periods without precipitation in the area, median 3.7 days. Wopt predicted from the soil map deviated strongly from Wopt predicted from the sample grids. Comparing estimates of Wopt from the large grid with measurements in the small grid showed differences corresponding to +/-2-3 days of evaporation. (C) 2007 Elsevier B.V. All rights reserved.

Sammendrag

Fine roots (2 mm) are very dynamic and play a key role in forest ecosystem carbon and nutrient cycling and accumulation. We reviewed root biomass data of three main European tree species European beech, (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.), in order to identify the differences between species, and within and between vegetation zones, and to show the relationships between root biomass and the climatic, site and stand factors.The collected literature consisted of data from 36 beech, 71 spruce and 43 pine stands. The mean fine root biomass of beech was 389 g m-2, and that of spruce and pine 297 g m-2 and 277 g m-2, respectively. Data from pine stands supported the hypothesis that root biomass is higher in the temperate than in the boreal zone.The results indicated that the root biomass of deciduous trees is higher than that of conifers. The correlations between root biomass and site fertility characteristics seemed to be species specific. There was no correlation between soil acidity and root biomass. Beech fine root biomass decreased with stand age whereas pine root biomass increased with stand age. Fine root biomass at tree level correlated better than stand level root biomass with stand characteristics. The results showed that there exists a strong relationship between the fine root biomass and the above-ground biomass.