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
Arnt Kristian GjertsenSammendrag
A multi-source forest inventory (MSFI) method has been developed for use in the Norwegian National Forest Inventory (NFI). The method is based on a k-nearest neighbour rule and uses field plots from the NFI, land cover maps, and satellite image data from Landsat Thematic Mapper. The inventory method is used to produce maps of selected forest variables and to estimate the selected forest variables for large areas such as municipalities. In this study, focus has been on the qualitative variables ‘dominating species group\" and ‘development class\" because these variables are of central interest to forest managers. A mid-summer Landsat 5 TM scene was used as image data, and all NFI plots inside the scene were used as a reference dataset. The relationship between the spectral bands and the forest variables was analysed, and it was found that the levels of association were low. A leave-one-out method based on the reference dataset was used to estimate the pixel-level accuracies. They were found to be relatively low with 63% agreement for species groups. An independent control survey was available for a municipality and estimates from the MSFI were compared to it. The levels of error were quite high. It was concluded that the large area estimates were biased by the reference dataset.
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Anna Arneberg Per Holm Nygaard Odd Egil Stabbetorp Bjarni D. Sigurdsson Edda Sigurdis OddsdóttirSammendrag
The aim of this study was to investigate variation in decomposition and vegetation due to afforestation. The ICEWOODS sites containing stands of different tree species and age in the western (Skorradalur) and eastern (Hallormsstaður) parts of Iceland were investigated during the summer of 2004. These stands were compared with treeless pastures. The planted stands represent chronosequences, i.e., different age classes within each tree species were studied. Decomposition was studied by a cotton strip assay. Cotton strip decomposition increased with incubation time and decreased with soil depth. The tree species can be ranked according to increasing decomposition in the following series: lodgepole pine < Sitka spruce< Siberian larch < mountain birch. In general, decomposition decreased with increasing age of the stands...
Forfattere
Philipp Gannibal Sonja Klemsdal Mark LevitinSammendrag
Alternaria tenuissima is a common pathogen on a number of plants described in several geographic regions of the world. Genetic variation within and between Russian Far East, North West and Caucasus populations of A. tenuissima from wheat was examined. In addition, genetic differences between isolates from various hosts were estimated. In total, 101 isolates of A. tenuissima were studied using amplified fragment length polymorphism (AFLP) with four primer combinations. Wright"s fixation index (F-st), gene flow (N-m) and gene diversity (H-s) were calculated. AFLP banding patterns indicated significant genetic distance and at the same time a low level of gene flow between the Far East and the two other groups of isolates originating from the European part of country. The degree of similarity between the North West and Caucasus populations was very high, as was the migration rate. Isolates analysed by UPGMA-based cluster analysis were grouped according to location of origin but irrespective of plant host. Based on the F-st value, the group of isolates originating from wheat and barley were not found to differ significantly from each other.
Forfattere
Zhihui Yang Bal Ram Singh Sissel HansenSammendrag
Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka(-1) and high level of 60 Mg ka(-1)) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1-2 mm) and microaggregates (<0. 106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5-1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5-1 and <0. 106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher ON, C/S and N/S ratios were found both in large dry aggregates (>20 and 6-20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0. 106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered.(C) 2007 Published by Elsevier B.V.
Forfattere
Zhihui Yang Bal Ram Singh Sissel Hansen Zhengyi Hu Hugh RileySammendrag
Understanding soil sulfur pools and associated aggregates S fractions can provide a platform for monitoring S dynamics in soils. A long-term experiment established in 1922 on an Aquic Eutrocryepts in South-eastern Norway was chosen to investigate the effects of long-term fertilization on S fractions in bulk soil and those associated with aggregates. Chloroform fumigation-extraction was used to determine Microbial biomass S (MBS) and the wet chemical analysis method was used to fractionate soil S into ester S (hydriodic acid reducible S), carbon-bonded S (Raney nickel reducible S) and residual S (Raney nickel non-reducible S). High farmyard manure (FYM) application resulted in higher MBS in bulk soil than nitrogen + potassium (NK) application, but it did not differ significantly from the control. Application of FYM at 60 Mg ha(-1) resulted into accumulation of total S, total organic S and carbon-bonded Sin bulk soils, while mineral fertilizer (nitrogen+phosphorus+potassium+sulfur [NPKS] and NK) and the medium rate of FYM did not increase the accumulation of total S and organic S fractions. The macroaggregate sizes (> 2 and 1-2 mm) and the finest aggregate size (< 0.106 mm) showed significantly greater total S concentration than other aggregate sizes. Ester S and residual S were predominant organic S fractions and they accounted for 39 to 52% and 38 to 51% of the organic S, respectively. The macroaggregate sizes (> 2 and 1-2 mm) contained the highest ester S, but microaggregates (< 0.106 mm) exhibited higher carbon-bonded S and residual S than other aggregates. In conclusion, the accumulation of S was dependent on fertilizer type, the rate of FYM application and aggregate sizes.
Sammendrag
Undersøkelser " Jord fra Møystad høsten 2003 " Effekt av ulik gjødsling gjennom 80 år på lagring av ulike svovelfraksjoner i jord " Effekt av størrelsen på jordaggregat på innhold av ulike svovelfraksjoner Resultat Mer enn 97% av S var organisk bundet. Gjødsling med 6tonn fast storfegjødsel per daa og år økte innholdet av total S, organisk bundet S og karbonbundet S i jorda, men ikke 4 tonn og ikke gjødsling med sulfatsvovel tilført gjennom mineralgjødsel (fullgjødsel). Størrelsen på jordaggregat påvirket forholdet mellom de ulike svovelfraksjonene i jorda.
Forfattere
Einar StrandSammendrag
Foredraget tok for seg rådgivning innen miljøspørsmål overfor jordbruket i Norge og presenterte norske regler og ordninger for redusere forurensing fra jordbruket.
Forfattere
Alhaji S. Jeng Roshan Bajracharya Bishal K. Sitaula Bed Mani Dahal Subodh ShermaSammendrag
Det er ikke registrert sammendrag
Forfattere
Alhaji Jeng Roshan Bajracharya Bishal Sitaula Bed Mani Dahal Subodh ShermaSammendrag
Agricultural intensification (AI) has for the past two or three decades been a widely practiced agricultural production system used in the mid-Hill watersheds of Central Nepal. This has been triggered by rising human and livestock populations which exert a serious pressure to the available agricultural land. The need to increase and secure agricultural output required greater use of agrochemicals (fertilizers and pesticides). The indiscriminate use of diverse types of pesticides and the exposure of farmers to these raised a number of questions relating to health, produce quality and environmental degradation. Kathmandu University in cooperation with Agricultural University of Norway and Jordforsk initiated a three year project in 2003 funded by the Norwegian Agency for International Development (NORAD) to, among others, provide: 1. A clearer understanding of the potentially adverse impacts of agriculture intensification in the mid-hills of Nepal; 2. Improved understanding of how market forces and external interventions may impact socio-economic development of rural communities and factors motivating farmers to adopt intensive production systems in the mid-hills; and 3. Useful policy formulation and implementation guidelines and tools for rapid assessment of land use and agricultural impacts of AI on soil and water quality and on environment and human health. LUKKET RAPPORT