Hopp til hovedinnholdet

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.

2011

To document

Abstract

The recent flooding episode in Norway from May this year shows the necessity of understanding the processes of water discharge from small tributaries feeding the larger river systems. The major objective of the recently started ExFlood project is to define and analyze measures to combat negative impact of extreme weather events on infrastructure in small watershed areas in Norway and to incorporate this in a land use planning tool. Urban, agriculture, nature, and forest areas and infrastructure elements demands different approaches concerning impacts of and opportunities for extreme weather events. The approach of the ExFlood project is to reduce the peak flow and delay the peak time to avoid damages on infrastructure. Three municipalities from different climate regions in Norway contribute to the project where the planning tool will be tested, and an experimental catchment site is selected to conduct in depth process studies.

2010

To document

Abstract

In Scandinavia, high losses of soil and particulate-bound phosphorus (PP) have been shown to occur from tine-cultivated and mouldboard-ploughed soils in clay soil areas, especially in relatively warm, wet winters. Omitting primary tillage (not ploughing)in autumn and continuous crop cover are generally used to control soil erosion. In Norway, ploughing and shallow cultivation of sloping fields in spring instead of ploughing in autumn has been shown to reduce particle transport by up to 89% on soils with high erodibility. Particle erosion from clay soils can be reduced by 79% by direct drilling in spring compared with autumn ploughing. Hence, field experiments in Scandinavia on ploughless tillage of clay loams and clay soils compared with conventional ploughing in autumn usually show reductions in total P losses of 10-80%, via both surface runoff and subsurface runoff (lateral movements to drains). However, the effects of not ploughing during autumn on losses of dissolved reactive P (DRP) are frequently negative, since the proportion of DRP losses without ploughing compared conventional ploughing has increased up to fourfold in field experiment. In a comprehensive Norwegian field experiment at a site with high erosion risk the proportion of DRP compared to total P has increased twice in water after direct drilling compared to ploughing before winter wheat. Therefore erosion control measures should be further evaluated for fields with a low erosion risk since reduction in PP losses may be low and DRP losses still high. Ploughless tillage systems have potential side-effects, including an increased need for pesticides to control weeds (e.g. Elytrigia repens (L.) Desv. ex Nevski) and plant diseases (e.g. Fusarium spp.) harboured by crop residues on the soil surface. Overall, soil tillage systems should be appraised for their positive and negative environmental effects before they are widely used for all conditions of soil, management practices, climate and landscape.