Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2006
Authors
May Sæthre Arne Hermansen Ragnhild NærstadAbstract
The western flower thrips, Frankliniella occidentalis (Pergande), is a highly polyphagous species with a host range including over 250 species of herbaceous and woody plants belonging to 62 families. F. occidentalis originates in western USA but has spread, since 1970, into many countries in Asia, Africa, Central and South America, Europe and Oceania. In southern regions of Europe the pest is found outdoors attacking the flowers of a number of host plants. In northern European countries it is a pest mainly in protected crops (i.e. glasshouses) attacking a number of ornamentals and vegetables. F. occidentalis is a vector of Tomato spotted wilt virus (TSWV) and several other viruses. Both these organisms are regulated as quarantine pests in the EPPO region (European and Mediterranean Plant Protection Organization). The first report of F. occidentalis in Norway was in 1986 and it spread very quickly within greenhouse environments. In 1987 the species was added to the A-list (quarantine pests with zero-tolerance on import to Norway) and a comprehensive spraying program to eradicate the introduced pest and stop further spread was developed. The thrips, however, continued to spread and in 1991 about 40% of all greenhouses in Norway were infested with F. occidentalis. A plan of action (Trips-aksjonen) to combat and eradicate F. occidentalis from Norway was executed in 1991. In spite of extensive efforts by growers and authorities they did not succeed in eradicating or stopping further spread of F. occidentalis. In 1997 the species was considered established in Norwegian greenhouses and it was therefore deleted from the Norwegian A-list. It is now under surveillance as a vector for TSWV (an A-list pest) and is treated as a quarantine pest if discovered in connection with TSWV. The introduction and establishment of F. occidentalis in Norwegian greenhouses has been a burden to both growers and the society. Growers have suffered financial losses in terms of costs of carrying out comprehensive quarantine instructions (1986-1996) as well as through direct crop loss and costs of control measures (1986-2006). Indirect economic impacts of F. occidentalis include the implications for growers due to the quarantine instructions (1987- 1996) such as increased labour to carry out the instructions; cost of pesticides; loss of production time during the quarantine and eradication period; loss of contracts when not able to deliver plants and seedlings on time; loss of reputation; and perhaps as a combination of the others also loss of future contracts. Growers have also suffered in terms of health risks as they have used pesticides more frequently and thereby been exposed to pesticides more often. Very rough estimates and assessments to predict potential crop loss caused by F. occidentalis suggests a worst case scenario (or 100% crop loss) to be about 1454.4 mill NOK per year (2003-numbers). Assuming that the proportion of infested greenhouses at any given time during the year is somewhere between 30-40%, then potential crop losses would be between 436-582 mill NOK per year. It should be underlined that these numbers are rough estimates only, not accurate measurements. Introduction/establishment of the species has resulted in an increased effort from extension service, phytosanitary authorities, and scientists, the costs involved are, however, difficult to assess. […]
Abstract
The aim of the present investigation was to study the effect of manure on retention of selenium (Se) in soil. Addition of cattle manure in combination with selenite and selenate reduced the adsorption of both anions to a loam soil in a batch experiment. The results were explained by the content of low-molecular-weight organic acids in the manure which compete with Se for the sorption sites. In a pot experiment with loam and peat soils and with two pH levels within each soil, cattle slurry added together with selenate was found to increase the Se concentration in grain at the highest pH level (6.1 and 6.8 for the loam and peat, respectively). At a lower pH (5.4 and 6.0 for the loam and peat, respectively) there was no significant effect of slurry on Se concentration in grain. Application of slurry also increased the residual effect of Se applied to the loam soil in the preceding growing season. In the peat soil, no residual effect of Se was found either with or without the addition of slurry.
Abstract
Early stage of grass maturity increased the total concentration of fatty acids (FA) and the concentration of alpha-linolenic acid in organic ley compared to normal stage. Organic ley with red clover resulted in higher concentration of alpha-linolenic acid than white clover. Unexpectedly, increased portions of clover in the ley resulted in lower total concentration of FA. Early harvested ley with red clover may result in forage with high concentrations of alpha-linolenic acid and thus provide a good basis for milk production with a healthy composition of milk fat with a low omega-6/omega-3 FA ratio.
Abstract
The effect of clover species and level of concentrate supplementation on milk fatty acid (FA) composition has been studied. White (WC) and red clover (RC) grown in mixture with grasses were preserved in round bales and fed to autumn calving dairy cows during the first 10 weeks of lactation. Milk FA was higher in linolenic acid, vaccenic acid and rumenic acid for RC than for WC silage (0.90 vs. 0.79 %, 1.52 vs. 1.36 %, 0.90 vs. 0.75 % for these 3 FA, respectively), and RC silage gave a higher n-3/n-6 milk FA ratio than WC (0.98 vs. 0.72). Concentrate supplementation decreased the level of vaccenic acid (1.21 vs. 1.68 %), linolenic acid (0.63 vs. 1.05 %) and the n-3/n-6 ratio (0.55 vs. 1.16) as compared with no supplementation, and the effect of supplementation was similar for the two silages
Abstract
The effect of clover species and level of concentrate supplementation on milk fatty acid (FA) composition has been studied. White (WC) and red clover (RC) grown in mixture with grasses were preserved in round bales and fed to autumn calving dairy cows during the first 10 weeks of lactation. Milk FA was higher in linolenic acid, vaccenic acid and rumenic acid for RC than for WC silage (0.90 vs. 0.79 %, 1.52 vs. 1.36 %, 0.90 vs. 0.75 % for these 3 FA, respectively), and RC silage gave a higher n-3/n-6 milk FA ratio than WC (0.98 vs. 0.72). Concentrate supplementation decreased the level of vaccenic acid (1.21 vs. 1.68 %), linolenic acid (0.63 vs. 1.05 %) and the n-3/n-6 ratio (0.55 vs. 1.16) as compared with no supplementation, and the effect of supplementation was similar for the two silages
Authors
Michelle de Chantal Kjersti Holt Hanssen Aksel Granhus Urban Bergsten Mikaell Ottosson-Löfvenius Harald GripAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Liv Sognnes Gustav Fystro Samson Øpstad Arve Arstein Trond BørresenAbstract
In terms of agricultural use, peat soils have weak structure, high water content, insufficient soil aeration and poor thermal properties resulting in suboptimal physical properties and yields of grass. During the period 1978 - 1995, a long-term field trial was conducted on highly decomposed peat soil in order to investigate the impact of adding mineral materials to improve soil characteristics and increase grass yield. Shell sand or moraine soil (200, 400 or 800 m(3) ha(-1)) was incorporated into peat soil. Generally, addition of both shell sand and moraine soil improved the physical properties of the soil and grass production. During the first nine years, shell sand ( 400 m 3 ha(-1)) was the most efficient. Thereafter, moraine soil ( 400 and 800 m(3) ha(-1)) seemed most beneficial. This study indicates that additions of shell sand or moraine soil to peat are appropriate methods to improve and conserve the physical properties and cropping potential of these vulnerable soils.
Authors
Ingvald Røsberg Jon Frank Arne O. StuanesAbstract
Soil uptake of N, P, and K from the unfertilized plots leads to a depletion of these elements, but also very little leaching. Upon addition of N, P, K, Mg, Ca, and S, soil uptake and nutrient accumulation in the soil usually increased at the same time. The high doses of N, P, K, and S in the "optimal" treatment gave a distinct response with higher uptake from the soil and higher accumulation in the soil. No P was leached from the soil, while about one fourth to one third of the applied N, K, and Mg were leached. The treatment induced an unacceptably high nitrate leaching, and must therefore be regarded as "suboptimal". (c) 2006 Elsevier B.V All rights reserved. Tree growth and nutrient cycling of N, P, K, Mg, Ca, S, and B were examined after four growing seasons in a pine ecosystem in southern Norway. The Scots pine (Pinus sylvestris L.) stand, growing on a Cambic Arenosol, was 33 years old and had a medium site index class. The randomized block experiment had six treatments and three replicates: (1) control, (2) 3000 kg per hectare lime, (3) 3000 kg per hectare dolomite, (4) 3000 kg per hectare dolomite and (5) 6000 kg per hectare dolomite, both treatments (4 and 5) with the fertilizers KCl and superphosphate, and (6) 3000 kg per hectare dolomite with KCl, superphosphate, NH4NO3, kieserite, and borax, and denoted as "optimal" treatment. The "optimal" treatment gave a significantly higher annual increase in tree height and diameter, stand basal area and volume than the control and lime treatments. The dry mass of needles and branches increased slightly for the treatments nos. 3-5 compared to the control and lime treatments, with the most distinct increase for the "optimal" treatment. Highest dry mass of stem wood + bark was found for the treatments nos. 3-6. The nutrient contents in needles were highest for the "optimal" treatment, while dolomite without fertilizer elevated the Mg content in both needles and branches. The nutrient concentrations in the current year's needles increased the most for the "optimal" treatment, except for Ca and Mg. The addition of lime gave the highest concentration of Ca in needles compared to the other treatments. The amounts of N, P, S, and B in the forest floor were also highest for the "optimal" treatment. Soil uptake of N, P, and K from the unfertilized plots leads to a depletion of these elements, but also very little leaching. Upon addition of N, P, K, Mg, Ca, and S, soil uptake and nutrient accumulation in the soil usually increased at the same time. The high doses of N, P, K, and S in the "optimal" treatment gave a distinct response with higher uptake from the soil and higher accumulation in the soil. No P was leached from the soil, while about one fourth to one third of the applied N, K, and Mg were leached. The treatment induced an unacceptably high nitrate leaching, and must therefore be regarded as "suboptimal".
Authors
Aksel GranhusAbstract
No abstract has been registered