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.
2002
Sammendrag
Development of environmentally and economically sound agricultural production systems is an important aim in agricultural policy and has a high priority in agricultural research worldwide. The present work uses results from the first complete crop rotation period (1990-1997) of the Apelsvoll cropping system experiment in south-eastern Norway, to discuss the effect of cropping systems and their management practices on environment, soil fertility, crop yields and the farm economy, and how this knowledge may be used to develop a more sustainable agriculture. The experiment includes conventional arable (CON-A), integrated arable (INT-A), ecological arable (ECO-A), conventional forage (CON-F), integrated forage (INT-F) and ecological forage (ECO-F) cropping systems which were established on model farms of 0.2 ha. On the basis of nutrient runoff, soil erosion and pesticide contamination, the following ranking from the most to the least favourable was made for environmental effects: INT-F> ECO-F> ECO-A> INT-A> CON-F> CON-A. Environmental effects such as N and P runoff losses were very much linked to the proportion of ley in the system. Thus, major improvements to reduce the effects of agriculture on nutrient runoff, cannot be achieved without changing the cropping systems in the direction of more mixed farming with reduced cropping intensity. The nutrient balance calculations showed that there were considerable deficits in the ecological systems, a fact which must be taken into consideration in the development of sustainable ecological cropping systems. The yield reduction experienced with integrated and ecological cropping, relative to conventional cropping, was smaller for forage crops and potatoes than for cereals. This suggests that it is easier to maintain the yield level by reduced cropping intensity in mixed farming systems with livestock than in arable farming systems without livestock. Because of the premium prices and government subsidies to ecological farming, the economic results were equally good in the ecological systems as in the conventional ones. Economically, integrated farming was less favourable than the other systems. It is concluded that, overall, integrated and ecological forage systems results in the least environmental harm, and based upon the present government subsidies, the forage systems also seem the most profitable, along with the ecological arable system.
Forfattere
Mehreteab TesfaiSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor Gunnar Vågen E. Yazew N. Haregeweyn F. Kebede S. Haptu K. Gebrekristos R. Pandey V. BallabhSammendrag
This report presents a synthesis of the findings under the Water Harvesting Study (WHS), as part of the Triangular Cooperation Project between Ethiopia, India and Norway. It is the final report as part of phase I of the project. The WHS was first initiated in late 1998 when the first of the field studies was undertaken in Sadguru Water and Development Foundation (SWDF) project areas in Gujarat, India. The findings of this and the other field studies in the villages of Mahudi, Kotda Khurd and Dhabudi (Gujarat), and Adiha and Dibdibo (Tigray) are summarised. The focus of the study has been on water harvesting and integrated watershed management. The field studies have covered various small scale water harvesting systems, including check-dams, river diversion schemes, micro-dams, and a wide range of soil and water conservation measures. The impacts of water harvesting and irrigation systems on soil quality, water quality, yields and the general livelihood of farmers have also been studied. The climatic and hydrological characteristics of the two study regions are presented and the water harvesting approaches of SWDF and REST are outlined. Then the findings of the field studies are presented and discussed for each of the study villages. The depth of the analysis and thus the discussion naturally varies somewhat since this depends on the amount and quality of available data, which varied greatly for the two study regions. Lack of existing data of appropriate quality has been a major challenge throughout the project. Field data collection has been particularly intensive for Tigray since very limited existing data were available for the two villages studied. The implementation of check-dams based on the SWDF design criteria was found to be highly relevant to Tigray. However, these systems need to be adapted to local conditions in Tigray, and more research is needed, particularly related to climate and hydrology, for such a transfer of technology to be successful.
Sammendrag
Uptake in grass crops of ammonium acetate lactate extractable K (KAL) and reserve K (interlayer K + structural K) in soil was studied in 16 field experiments at different locations on a range of mineral soil types in Norway. The K uptake from soil, both from KAL and reserve K, was considerable, often even at the highest level of K fertiliser. During three years, only on the sandy soils with a low level of acid soluble K (KHNO3 minus KAL) was there a yield response to K fertilisation. The KAL values declined rapidly and flattened off at a "minimum level" which differed with soil type. This minimum level for KAL is a useful parameter in fertiliser planning, because the grass usually took up the K in excess of the minimum level over two years. The minimum value of KAL was significantly correlated with the content of clay + silt in soil. The decrease in KAL during the growing season was closely correlated to the KAL value in spring minus the minimum value and, therefore, the amount of K supplied to the grass from the KAL fraction can be calculated. Furthermore, the KAL value for the following spring may be estimated. The release from reserve K was partially related to acid soluble K.
Forfattere
Svein Ole BorgenSammendrag
The article evaluates the usefulness and shortcomings of agency theory as a framework for discussing the future of Norwegian agricultural cooperatives. The first argument is that agency theory ignores the significance of the traditional collective thinking in Norwegian agricultural cooperatives. In this respect, agency theory is incomplete and its explanatory power is low. The second point is that, nevertheless, the value of applying agency theory as a conceptual tool may increase in the close future, due to the emerging of novel industrial strategies and new cooperative forms. Some of the crucial agencyproblems may come to the forefront, and increasingly imprint the agenda of Norwegian agricultural cooperatives.
Forfattere
Helge Lundekvam Eirik Romstad Lillian ØygardenSammendrag
Det er ikke registrert sammendrag
Forfattere
Johannes DeelstraSammendrag
Summary: The report describes the erosion problems in Sub-Basin III, Managua, Nicaragua and proposes measures to alleviate these. Soil loss in the upper part of the catchment causes serious sedimentation in the downstream reaches of the open water courses, resulting in a reduced discharge capacity for water. This in its turn leads to flooding of urban areas during high rainfall periods and under extreme events can lead to closure of the international airport. In addition does the soil loss from agricultural land contribute in the ongoing deterioration of the water quality of Lake Managua while at the same time leading to a decrease in soil fertility and production capacity. An assessment is made of the present soil loss from agricultural land in the Subcuenca III and recommendations are proposed concerning soil conservation measures. Soil loss has been calculated using the Universal Soil Loss Equation (USLE). Very high figures for soil loss were obtained and the question has been raised whether these were realistic. However, the calculations were seriously hampered due to the lack of input data while at the same time were no data were available for validation.. Therefore, also proposals are given for a measurement programme to improve data availability and to be able to verify calculated soil loss. The report is the original to the report " Estudio Agrohidrológico" which is part of the "Estudio Agroecologico y de Drenaje Pluvial de la Subcuenca III de la Cuenca Sur del Lago de Managua" (Agro-Ecological and Rainwater Drainage Study of Sub-Basin III of the Southern Basin of Lake Managua).
Forfattere
Arild AndersenSammendrag
Minerfluefaunaen ble undersøkt ved hjelp av håving langs kanten av korn- og grasfelt på økologiske og konvensjonelle gårder i en treårsperiode. Generelt avtok biodiversiteten utover i åkrene, og var høyere på økologiske enn konvensjonelle gårder.
Forfattere
Dan AamlidSammendrag
Extended summary and conclusions The Pechenganikel combine in the Nikel-Zapolyarny area was established in 1933. During the first 30 years of production, 100 000 tons of sulphur dioxide (SO2) were emitted annually. Since 1971, nickel from the Norilsk ores in Siberia have been processed in the smelters. The Norilsk ore contains more sulphur than the Nikel ore. As a result of the processing of this sulphur-rich ore, emissions of SO2 increased rapidly, reaching 400 000 tons in 1979. Current annual emissions are much lower, about 150 000 tons. However, the present emission is still above the critical level for sensitive biota in the Nikel-Pasvik area. Investigations of soils show that the soil layers are contaminated by heavy metals (nickel and copper). The results also indicate an influence on soil fertility expressed as changes in base saturation (BS), cation exchange capacity (CEC) and soil acidity. According to the calculations (critical loads) future sulphur deposition has to be reduced to very low levels in order to stop the ongoing soil acidification. Air pollution influence has had severe effects on forest vegetation in the Nikel-Pasvik area. Trees, vascular plants, mosses and lichens are all affected. In the close vicinity of the smelters forests are dead or severely damaged. Visible injuries to vegetation caused by SO2 have some years been frequent. Symptoms are recognised on Scots pine (Pinus sylvestris) and downy birch (Betula pubescens), which are the dominant tree species in the region, and on other plants, e.g. dwarf birch (Betula nana) and bilberry (Vaccinium myrtillus). The species composition of the ground vegetation in the forest has been influenced, and epiphytic lichen vegetation has been severely influenced over large areas. Critical levels are exceeded on more than 3200 square kilometres of Russian and Norwegian territory. Air pollution has reduced invertebrate and animal diversity due to lack of forest vegetation and contamination of surface soils in the vicinity of the nickel smelters. Small vertebrates are impacted by an increased heavy metal content in the liver. However, no negative health effects to reindeer are foreseen. Long-term monitoring of water chemistry in lakes and rivers has revealed that extensive surface water acidification has taken place, particularly on the Norwegian side of the border. Critical loads are exceeded in large areas of Sør-Varanger municipality, especially in the Jarfjord area, and in areas situated around Nikel and Zapolyarny. However, on the Russian side, the contamination of lakes by the heavy metals (nickel and copper) is more severe than acidification, especially in the vicinity of the smelters, where damage to fish populations as well as phytoplankton and invertebrate communities are observed. Studies of human health in the Nikel-Pasvik area revealed no major health effects that can be ascribed to the air pollution by nickel and sulphur dioxide in the Nikel-Zapolyarny area or in the Pasvik valley. The most severe effects of air pollution in the border areas between Norway and Russia, caused by sulphur dioxide emission from Nikel and Zapolyarny, on the terrestrial and aquatic ecosystems seem to be on vegetation, surface water and soils, and thus also on other compartments of the ecosystem.
Forfattere
Isabella BørjaSammendrag
Det er ikke registrert sammendrag