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.
1999
Sammendrag
This report focuses on agriculture and its impacts in rural areas. Agriculture is an important activity in the Norwegian periphery, directly and indirectly. A deregulation of agriculture will most probably have negative impacts on agricultural production and employment. This, in turn, will have negative impacts on other sectors. Since agriculture is overrepresented in the periphery, and there are few alternative sources of employment, reduced activity in agricultural can lead to increased centralisation. This can be a problem since the relatively low population densities already imply a danger of depopulation in the periphery. Some motivations for regulating agriculture are based on the sector's importance in the periphery. Regulations are also motivated by other facts. It is very difficult to distinguish precisely between rurality and other motivations. However, part of the motivation is agricultural production itself, or aims that can be deducted from production. Distribution of income is an example of this. From a theoretical point of view, subsidies should, in order to be as efficient as possible, be directed directly towards the problems they are meant to cure. If the aim for granting agricultural support is rural development and not agricultural production, then it is better to grant subsidies that do not depend upon production. Rural development (RD) can be thought of as complementary to agricultural production (AP): (*) RD = f(AP), f'(AP) > 0 This means that you get more RD if AP increases, and less RD if AP decreases. By subsidising AP, you will automatically get more RD. The function (*) does not, however, say anything about the efficiency of subsiding AP for gaining RD, compared to using the same amount of subsidies directly at gaining RD. The function does not describe whether subsidies that are production dependent are preferable to non-production subsidies from a rural development point of view. Using the function (*) and the fact that the secondary effects of reducing agricultural subsidies may be substantial in the peripheries, one may argue, however, that agriculture is important and that agricultural production is an essential industry for rural development. We would also like to underline the fact that agricultural has several non-food impacts and that multifunctionality is much more than rural development. It is especially difficult to distinguish between «rural development» and «cultural landscape». The relationship between them should probably be discussed further.
Sammendrag
In this paper we first discuss the consumption behaviour of Norwegian farm households. Then, possible consumption models are outlined and our data sample is described. In the next section we discuss the use of panel data methods to estimate our consumption function. Finally, the results from estimating a consumption function with the DPD computer program are discussed. The preliminary results indicate that the GMM estimation using the system estimator of Blundell and Bond (1998) may be superior to the other methods. The parameter of the lagged dependent variable is inside the limits indicated by the OLS and the within estimator. The second lag of the dependent variable is rejected as an instrument and there are strong indications of serial correlation. Later on, we have to transform the model to make the serial correlation disappear. In a later version of this paper we will test if the MPC is changing over time. We will also test if there are different effects from price- and production dependent agricultural income and other income.
Sammendrag
Med utgangspunkt i ein rekneskapsmodell på sektornivå for hushaldsinntekter for jordbrukarhushald drøftar vi i dette notatet enkelte spørsmål som bør/må avklarast før det eventuelt er mogeleg å utvikle prognosemodell for utvikling i slike hushaldsinntekter. Eit spørsmål er om ein kan gå ut frå profittmaksimering eller ein annan målfunksjon. Usikkerheit er eit sterkt argument mot profittmaksimering. Eit anna moment er at jordbrukarhushald er både produsentar og konsumentar. Nyttemaksimering kan vere meir relevant enn profittmaksimering, eventuelt at ein nyttar modellar som forutset båe delar. Det er grunn til å tru at på kort sikt (innafor ein produksjonsperiode) produksjonsopplegg og arbeidsfordeling svært fast. Inntektene blir difor direkte avhengige av eventuelle endringar i prisar og andre eksterne faktorar, som t.d. været. På lengre sikt, men framleis kort sikt i økonomisk meining, er det mogeleg å endre produsert kvantum og arbeidsinnsats i jordbruk og annan aktivitet. I notatet er tre modelltypar drøfta: økonometriske modellar, optimeringsmodellar (kortsiktige) og langsiktige modellar (eventuelt med tidsperspektiv innebygt). Under kortsiktige optimeringsmodellar har ein i hovudsak sett på rekursiv lineær programmering. Hovudvekta i dette notatet er ikkje på langsiktige modellar, så det er i hovudsak dei to første modelltypane som er mest aktuelle. Både økonometriske modellar og rekursiv programmering byggjer på ein føresetnad om at bøndene i framtida reagerer omtrent som dei har gjort i tidlegare år. Spesielt i sektormodellar er det grunn til å ta eksplisitt omsyn til teknologiske endringar. Desse skuldast i stor grad forsking og utvikling utanfor jordbruket, og vert innebygde i innsatsfaktorar til jordbruket. I økonomiar i vekst er det erfaringsmessig sterkare auke i lønsnivå utanfor jordbruket enn i jordbruket. Dette kan delvis oppfattast som ein verknad av teknologisk utvikling i dei enkelte næringar og etterspørselsforhold. På den andre sida har jordbruket mykje langsiktig og spesialisert kapital. Dette kan bidra til at tilpassingane i jordbruket går relativt seint, at eventuelle overskotsproblem er vanskeleg å få slutt på, og at inntektsnivået (faktorinntekta) er relativt lågt. I dette arbeidet har vi ikkje forsøkt å kvantifisere modellen.
Sammendrag
This report was written in connection with the preparations of the Norwegian authorities for the new round of WTO negotiations on further liberalization of world trade. The report surveys the natural conditions in Australia, France, New Zealand, Norway and the USA, and studies their influence on agriculture, e.g., on farm size, farmland distribution, types of production and production costs. However, it is not easy to limit the analysis to merely the natural conditions for farming, since a number of other political, legal, economic, historic and cultural factors also determine the conditions for agriculture in a country. The report includes agroclimatic data such as length of growing-season, temperature sums, mean temperatures and mean precipitation. Not surprisingly, the climate in Australia and New Zealand is significantly different from the climate in Norway. In these two countries, low temperatures are not a major growth-limiting factor, as they are in (parts of) France, Norway and the USA. Especially in Australia, growth is mainly limited by too high temperatures, excessive radiation, evaporation and lack of rainfall. [...]
Sammendrag
The study examines the economics of combined milk and meat production as an alternative to the current specialised milk production on Norwegian goat. The reasons for the study are 1) to increase goat farm incomes,2) to improve the annual distribution pattern of goat milk and 3) to reduce negative publicity of farmers killing surplus goat kids just after birth. The most promising management practice would be to change the time of kidding from February to late April or May, combined with suckling the kids during the daytime until August. The kids are to be slaughtered in August in order to utilise the summer grazing period and market the kids the month before start of the lamb slaughter season. While the kids are being suckled, the does are milked once per day and after weaning the does are milked twice a day, thereby increasing milk deliveries during autumn and winter when milk prices are higher. A discussion of how the natural conditions and the Norwegian agricultural policy contribute to the results increases the value of the study.
Forfattere
Carl Gunnar FossdalSammendrag
Plants are exposed to a great number of microorganisms under natural conditions. Pathogenic fungi and oomycetes are the main factors contributing to plant diseases, thus further understanding of plant-pathogen interactions may provide information leading to new strategies for reducing the damage caused by these pathogens on economically important trees and crops. Active plant-responses to microorganisms differ with respect to the degree of responses and with respect to the outcome of the interaction. In response to pathogens, active plant-defenses can be induced. Both local and systemic plant defense-response may be induced by pathogens. This thesis present indications of both local and systemic host responses at the molecular and cellular levels, using the conifer Norway spruce as a model host to study plan-pathogen interactions. Norway spruce seedlings were infected separately with the pathogenic fungi Heterobasidion annosum and Ceratocystis polonica, the pathogenic oomycete Pythium dimorphum and the ectomycorrhizal fungus Laccaria bicolor, to study the local and systemic effects of the infections at the cellular and molecular level. Increased levels of lignification was seen within 2 to 4 days in response to the pathogens, and indications of cytoplasmic translocations were also observed as a response to hyphae invading the root. Initially, a defense related plant peroxidase cDNA SPI2 (spruce pathogen induced 2) from Norway spruce roots was isolated and sequenced and found to encode a predicted 34kD SPI2 protein. The 34kD SPI2 protein was detected both in the root and shoot of Norway spruce seedlings, and accumulated as a local response to infection with the pathogenic oomycete Pythium dimorphum. In addition, two 38kD and 39kD SPI2 related proteins were detected in roots only after infection. Interestingly, increase levels of the 39kD SPI2 related protein was also detected in shoots of infected seedlings as a systemic response to infection. The putative plant defensin SPI1 (spruce pathogen induced 1) from Norway spruce has been proposed a role in the defense against pathogenic fungi and oomycetes. Here the predicted 5kD SPI1 protein was detected in Norway spruce seedlings and found to accumulate in roots during development. Notably, the putative plant defensin SPI1 lined the wall of cortical root cells, and in roots invaded by P. dimorphum the SPI1 protein was found associated with the invading hyphae. This supports the hypothesis that SPI1 has a role in the defense against pathogenic oomycetes and fungi. The possible protective role of prior colonization by the ectomycorrhizal fungus on later challenge with the pathogen C. polonica, previously known to be vectored to the tree stem by bark beetles, was also examined. Surprisingly, C. polonica was able to invade also roots of both mycorrhizal and non-mycorrhizal seedlings. Not only induced or enhanced plant responses were observed, but also reduced levels of defense-related proteins were observed in the infected roots at the later stages of infection. Decreased levels of SPI1was detected within 96 hours after infection in response to the pathogens tested. Reduced levels of the corresponding transcript was also detected indicating a suppression of host responses by the pathogens. Increased proteolytic activity was detected in infected roots, and from the pathogens. Proteolytic degradation of host proteins by fungal secreted proteases may reduce the levels of potentially antimicrobial proteins enabling the pathogens to effectively invade the roots. Reduced levels of the SPI1 in roots, was found also in response to the ectomycorrhizal fungus L. bicolor. Reduced levels of the peroxidase isozymes at the later stages of the infections, was also observed. Thus, suppressor(s) may be produced by both the pathogens and by the ectomycorrhizal fungus during infection, reducing the host responses and contributing to successful colonization of the roots.
Forfattere
Per Holm Nygaard Torbjørn ØdegaardSammendrag
Vegetation data were collected in 1931, 1961 and 1991 from permanent plots in a boreo-nemoral forest 20 km north of Oslo in southern Norway. Major changes were found in the vegetation composition during 60 years. The main changes were a reduction in the frequency and frequency of joint occurrence of species like Calluna vulgaris, Vaccinium uliginosum, Trientalis europaea, Maianthemum bifolium, Melampyrum pratense, Cornus suecica, Andromeda polifolia, Eriophorum vaginatum, Vaccinium oxycoccus, Pleurozium schreberi, Hylocomium splendens, Ptilium crista-castrensis, Dicranum fuscescens and Ptilidium ciliare. The observed changes were interpreted as induced by internal processes e.g., a long-term change from paludified forest to mesic forest. In particular the growth of Picea abies seems in particular to be a main driving force. The dominance of Picea abies and Vaccinium myrtillus appears to have made the conditions more unfavourable to other species. A doubling of the living stem biomass of P.abies during the last 67 years shows that this old-growth forest has not reached a steady state. Species like Deschampsia flexuosa and Molinia caerulea did not increase in frequency as has been demonstrated in response to nitrogen deposition elsewhere in northern Europe. The results of this study indicate that protection from logging has promoted the reduction of species in the field layer and bottom layer. This study questions if monitoring of forest vegetation should be restricted to protected forests as is the practice in Scandinavia today. We recommend that areas with some kind of selective cutting are also used for monitoring of forest vegetation
Forfattere
M. Lavoie Peder GjerdrumSammendrag
The aim of this study has been to investigate the effects of high temperature drying on the equilibrium moisture content, to verify the presence of hysteresis and to screen the effects of high temperature on timber quality. Further, we wanted to utilise the laboratory kiln at Forestia Sokna in a pilot project, to learn more about the experimental possibilities connected to this equipment. The hypothesis was that the equilibrium moisture content will decrease as the drying temperature increase. Five series of twelve spruce wood samples each were prepared to verify this hypothesis: air-dried (green samples), moist samples for desorption and dry samples for adsorption for the ordinary-progressive (72 C) and for the high temperature kilns (115 C). The tension has been measured to compare the timber quality between ordinary-progressive and high temperature kilns. The conclusion is that there was too much stochastic noise to verify the initial hypothesis. Consequently it was impossible to confirm the presence of hysteresis. There are interesting observations to make in further research on how fast the equilibrium moisture content is reached according to the drying temperature. This experiment has been accomplished using Norway spruce, and further research should include Scots pine or other coniferous species.
Sammendrag
Potential response of forest soils to sulphur deposition in the Norwegian-Russian border area in the surroundings of the Pechenganikel smelters, the major sulphur emitters in the northern Europe, has been assessed with the PROFILE model. The release rate of base cations due to weathering range from 0.05 to 0.28 kmol(c)/ha/yr in the 0 - 50 cm soil layer, thus demonstrating the high sensitivity of the coarse and thin podzols studied. Calculated steady-state BC/Al values are significantly lower than the presumed critical value of 1, which indicate possible negative effect on vegetation through soil acidification. According to the model calculations future sulphur deposition have to be very low in order to stop the ongoing acidification and prevent vegetation damage. However, model assumptions, uncertainty in input data and critical chemical values applied implies that modelling results must be interpreted carefully
Forfattere
Svein Ola MoumSammendrag
The article presents a mapping system describing agricultural resources in scales ranging from 1:100.000 down to 1:300.000, with respect to a prototype covering an area of Nord-Gudbrandsdalen district. The maps cover all Norwegian land types grouped into 13 classes.Ancillary data is widely used and the area where new interpretation is needed was thus limited to dry land above the tree line. The land type of these areas was interpreted from Landsat TM images. Maps produced with this system offer a coherent overview of the landscape and land types for large areas. Land type statistics from these small-scale maps is only recommended when the claim of accuracy is low and statistical bias is acceptable. Use of the maps for regional and agricultural planning as well as for environmental impact assessment is discussed.