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.
2021
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Abstract
Increasing atmospheric nitrogen deposition and climate change are considered the main factors accelerating the long-term growth of forests. Quantification of changes in growth rate can be extremely useful in monitoring and assessing the impact of climate change on site productivity. In this study, we carried out a country-wide analysis of long-term (100 years) dynamics and changes in the height growth rate and site index (SI) of Scots pine in Poland. To ensure representativeness we used a large sample of stem analysis trees collected on 312 plots selected using stratified sampling. To control the effect of site fertility and thus avoid the over-representation of older stands on infertile sites, we measured a range of soil properties that, together with environmental indicators characterising climatic conditions and topography, were used in growth trend modelling as explanatory variables. We found that trees planted in successive years have grown faster. The SI calculated for individual trees is linearly dependent on the year of germination and with increasing age of germination, the SI at the base age of 100 years has increased by 8.4 cm per year. Despite the differences in the growth dynamics of pines planted in different germination years, tree growth follows the same growth pattern. The observed continuous changes in site productivity correspond to an increase in the SI by over 29% between 1900 and 2000. A consequence of continuous changes in site conditions and height growth rate is ambiguity in derived SI values. Under changing site conditions, SI values calculated based on stand height and age depend not only on site productivity but also the year of germination. As a consequence, stands growing under identical site conditions show different SIs, which should be acknowledged if the SI is to be used in forest management. Therefore, determining the SI of newly established stands based on the SI of older generations requires the application of an amendment to account for stand age. Continuously improving our understanding of potential climate change impacts on forest ecosystems is essential and provide information to support forest managers seeking to develop effective adaptation measures and determine sustainable forestry production. As such, our results provide valuable support when making long-term decisions and developing effective adaptation strategies in forest management.
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No abstract has been registered
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No abstract has been registered
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Self-sufficiency with feed (SSF) is a basic principle in organic animal production. The current regulations do not impose strict requirements for SSF at farm level, but further restrictions are expected in future. The aim of the present work was to quantify SSF on a range of organic dairy farms in Norway and study farmers’ strategies to produce milk with a high degree of SSF. Nine farms were selected for interview and data collection. On farm level, the proportion of SSF varied between 66 and 99 %. SSF increased to 88-100 % when expressed on national level. Land area is among the limiting factors for famers to reach higher SSF while maintaining the milk production level. A lower proportion of concentrates in the diet seems to have as strong impact on SSF as using own cereals and protein crops as feed, but milk production per total feed production area was highest for the latter. The farmers’ goals and actions are important driving forces to develop more SSF in dairy production systems.
Authors
Simo Maduna Jon Aars Ida Marie Luna Fløystad Cornelya Klutsch Eve Marie Louise Zeyl Fiskebeck Øystein Wiig Dorothee Ehrich Magnus Andersen Lutz Bachmann Andrew E. Derocher Tommi Nyman Hans Geir Eiken Snorre HagenAbstract
No abstract has been registered
Authors
Eva BrodAbstract
No abstract has been registered
Authors
Tania Gomes Agathe Bour Claire Coutris Ana Catarina Almeida Inger Lise Nerland Bråte Raoul Wolf Michael Bank Amy LusherAbstract
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Authors
Philippe Jeanneret Gisela Lüscher Manuel K. Schneider Philippe Pointereau Michaela Arndorfer Debra Bailey Katalin Balázs András Báldi Jean-Philippe Choisis Peter Dennis Mario Díaz Sebastian Eiter Zoltán Elek Wendy Fjellstad Thomas Frank Jürgen Kurt Friedel Ilse R. Geijzendorffer Pippa Gillingham Tiziano Gomiero Gergely Jerkovich Rob H. G. Jongman Max Kainz Anikó Kovács-Hostyánszki Gerardo Moreno Juri Nascimbene Marie-Louise Oschatz Maurizio Guido Paoletti Jean-Pierre Sarthou Norman Siebrecht Daniele Sommaggio Sebastian Wolfrum Felix HerzogAbstract
No abstract has been registered
Abstract
Plant-parasitic nematodes (PPN) cause significant yield reduction in commercial pineapple (Ananas comosus) worldwide. In Kenya, few nematode studies have been conducted, although the main commercial pineapple producer has sole dispensation to use Telone II (1,3-Dichloropropene) indicating the magnitude of the nematode problem. This study was conducted with the aim to investigate the population densities and diversity of nematodes in two commercial plantations with two contrasting management practices. We additionally assessed the influence of crop age and compared this with nearby smallholder pineapple production systems. Soil and root samples were collected from fields of different ages in each commercial plantation and from 29 smallholder fields. A total of 18 genera were associated with pineapple, with a relatively greater diversity found in smallholder than commercial farms. The most prevalent genus was Meloidogyne spp. (M. javanica) followed by Helicotylenchus spp., Tylenchus spp. and Aphelenchoides spp. PPN densities were higher in relatively older fields of 24 and 36 months than from fallow and 3-month-old fields. Regression analysis additionally demonstrated the rise of PPN densities with age of pineapple fields, especially Meloidogyne spp., while free-living nematode densities declined. This study provides an indication of the high level of PPN infection in pineapple in Kenya, which would constitute an important factor contributing to low yields. The study confirms an obvious need for pineapple producers to control PPN to improve crop yields.