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.
2012
Abstract
Plant parasitic nematodes associated with potato feed on roots and/or tubers. About 70 species, representing 24 genera, have been reported from potato. Since nematodes attack underground plant parts, there are no reliable foliar symptoms to show that nematodes may be the major cause of poor growth and reduced tuber yields. Potato roots damaged by nematodes may show lesions, abnormal proliferation of lateral roots, emerging white females and brown cysts. Nematode attacks may render plants vulnerable to other pathogens, so disease caused by microorganisms may have nematodes as an etiological component. Therefore, nematode damage may often have been attributed to other factors. In Scandinavia, potato cyst nematodes (Globodera rostochiensis and Globodera pallida) are by far the most important nematodes on potato. In Norway, the cost of compensations schemes due to imposed statutory regulations of potato cyst nematodes may some years exceed the compensation for any other pests or diseases organism in agriculture. Other important nematodes include root lesion nematodes (Pratylenchus spp.), stubby root nematodes (Trichodorus spp. and Paratrichodorus spp.), and potato rot and stem nematodes (Ditylenchus spp.). Root knot nematode Meloidogyne hapla is considered less important. Meloidogyne chitwoodi and Meloidogyne fallax are not known to be present in Nordic countries. In the control, crop rotations using non-host crops, alternating susceptible and resistant potato cultivars, are an important control measure. However, the use of resistant potato cultivars requires knowledge of the species and pathotypes present in the field.
Authors
Christer MagnussonAbstract
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Marte Meland Celine Rebours H. Barros Alexandra Marques Tim Attack Katia Frangoudes Igotz Gallestegi Marie Lesueur Sebastien Pien Martin Walsh Julie MaguireAbstract
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Trond RafossAbstract
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Erik J. JonerAbstract
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Signe Kynding Borgen Hanne Lunde Weichel Lars Bakken Marina Azzaroli Bleken Tor Arvid BrelandAbstract
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Abstract
The current IPCC guidelines define an estimate for the fraction of mineral fertilizer and animal waste (manure) lost to leaching and runoff (FracLEACH). The FracLEACH default is 30 %. In Norway, 18 % has been used based on calculations made in 1998 (Vagstad et al., 1998). The main purpose of this study was to give an updated estimate of nitrogen (N) leaching in relation to the amounts of N applied in agriculture (FracLEACH). The term losses in this report include both surface and subsurface runoff. The estimates of FracLEACH presented in this report were based on data from the Agricultural Environmental monitoring program (JOVA). The JOVA-program includes catchment and field study sites representing typical situations in Norwegian agriculture with regard to production system, management, intensity, soil, landscape, region and climate. Data from plot- scale study sites confirmed the level of N leaching from the agricultural areas within the JOVA catchments. The overall FracLEACH estimated in this study was 22 % of the N applied. This average covers a variation between sites from 16 % on grassland in Valdres to 44 % in intensive vegetable, potato and cereal production areas in the southernmost part of Norway. Runoff is the most significant parameter for the difference in FracLEACH between catchments. In addition, production system and to some degree soil type are important for FracLEACH. It is thus suggested to use different FracLEACH-values for the different production systems and adjust FracLEACH according to average runoff for the region.
Authors
Kjell Andreassen Bernt-Håvard ØyenAbstract
Growth conditions in Fennoscandia are characterized by relatively short growth seasons and cold winters, from 130 growth days (T 5C) in the far north high mountains to more than 200 in south Sweden and Norway. Growth models from different regions predict different forest growth.In this study, we compare some models commonly applied in forest growth prognosis in pure even aged stands of Norway spruce, Scots pine and birch in Finland, Sweden and Norway. The objectives is to identify behavioural properties, accuracy and bias in selected Nordic growth models using a wide-ranging test data set from permanent research plots in Norway.Present tentative conclusions about the accuracy of growth outside the geographical range of the original base materials. With four different response variables in the tested models we emphasized relative deviations rather than absolute values as most suitable for comparisons. The models were compared by statistical tests, a visual inspection of the smoothed curve of the relative deviations in different stand properties and ranked due to their performance.We observed site index, stand density and mean tree size as the three main components in the models. For Norway spruce a basal area increment model from Sweden had the lowest standard deviation with 23 %. The mean R2 between residuals and stand characteristics from this model was also low (1.3 %), which indicates that variables are well included in the model. For Scots pine and birch, Finnish percent volume growth models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7 %, respectively. Several of the models from Sweden and Finland predict the growth as well as stand models frequently in use in Norway.