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.
2017
Authors
Trond MæhlumAbstract
No abstract has been registered
Abstract
Increased nutrient cycling in the agri-food system is a way to achieve a healthier nutrient stewardship and more sustainable food production. In life cycle assessment (LCA) studies, use of recycled fertilizer products is often credited by the substitution method, which subtracts the environmental burdens associated with avoided production of mineral fertilizer from the system under study. The environmental benefits from avoided fertilizer production can make an important contribution to the results, but different calculation principles and often implicit assumptions are used to estimate the amount of avoided mineral fertilizer. This may hinder comparisons between studies. The present study therefore examines how the choice of substitution principles influences LCA results. Three different substitution principles, called one-to-one, maintenance, and adjusted maintenance, are identified, and we test the importance of these in a case study on cattle slurry management. We show that the inventory of avoided mineral fertilizer varies greatly when the different principles are applied, with strong influences on two-thirds of LCA impact categories. With the one-to-one principle, there is a risk of systematically over-estimating the environmental benefits from nutrient cycling. In a sensitivity analysis we show that the difference between the principles is closely related to the application rate and levels of residual nutrients in the soil. We recommend that LCA practitioners first and foremost state and justify the substitution method they use, in order to increase transparency and comparability with other studies. © 2017 Elsevier B.V. All rights reserved.
Abstract
No abstract has been registered
Abstract
Herbage yield responses to K fertilizer application are variable in Norwegian grassland. Excessive K application may increase the risk of grass tetany (hypomagnesaemia) and milk fever (hypocalcaemia). We analysed a series of K fertilizer experiments on grassland with respect to their herbage yields and mineral composition. Our results show the importance of native soil K reserves when considering the need for K application. Soils with a high content of acid-soluble K showed no response to K fertilizer application. The critical K content in grass with respect to yield was estimated to be 17.7 g K/kg DM in the first cut and 20.3 kg K/DM in the second cut, while the critical K/N relationship was found to be 0.83 when a maximum yield reduction of 2.5% was used as a criterion. In these trials, soils with a high content of acid-soluble K had the greatest risk of grass tetany and the highest values of cation–anion balance. Application of potassium chloride had little effect on the cation–anion balance, and thereby the risk of milking fever, because there was a corresponding uptake of K and Cl ions.
Abstract
Specialized agricultural production between regions has led to large regional differences in soil phosphorus (P) over time. Redistribution of surplus manure P from high livestock density regions to regions with arable farming can improve agricultural P use efficiency. In this paper, the central research question was whether more efficient P use through manure P redistribution comes at a price of increased environmental impacts when compared to a reference system. Secondly, we wanted to explore the influence on impacts of regions with different characteristics. For this purpose, a life cycle assessment was performed and two regions in Norway were used as a case study. Several technology options for redistribution were examined in a set of scenarios, including solid–liquid separation, with and without anaerobic digestion of manure before separation. The most promising scenario in terms of environmental impacts was anaerobic digestion with subsequent decanter centrifuge separation of the digestate. This scenario showed that redistribution can be done with net environmental impacts being similar to or lower than the reference situation, including transport. The findings emphasize the need to use explicit regional characteristics of the donor and recipient regions to study the impacts of geographical redistribution of surplus P in organic fertilizer residues.
Authors
Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Johannes DeelstraAbstract
In Norway, and many other countries, subsurface drainage systems are a necessity to practice agriculture. Drainage systems, through control of the groundwater level, have a direct influence on the soil moisture content. To facilitate tillage practices and harvesting depending on soil type, the soil moisture content has to be at 80 – 90% of the field capacity in the top 20 cm of the soil profile. The main objective was to get information about the half time , i.e. the time required to reduce the runoff to 50% of the runoff at the onset of a recession period. The average half time for the small field scale catchments varied from 6 – 16 hours, indicating a fast drawdown of the water Level. The analysis of subsurface drainage is carried out as part of IRIDA, an EU/JPI funded project.
Authors
Anne Gobin Kurt Christian Kersebaum Josef Eitzinger Miroslav Trnka Petr Hlavinka Jozef Takác Joop Kroes Domenico Ventrella Anna Dalla Marta Johannes Deelstra Branislava Lalic Pavol Nejedlik Simone Orlandini Pirjo Peltonen-Sainio Ari Rajala Triin Saue Levent Saylan Ruzica Stricevic Visnja Vucetic Christos ZoumidesAbstract
Crop growth and yield are affected by water use during the season: the green water footprint (WF) accounts for rain water, the blue WF for irrigation and the grey WF for diluting agri-chemicals. We calibrated crop yield for FAO’s water balance model “Aquacrop” at field level. We collected weather, soil and crop inputs for 45 locations for the period 1992–2012. Calibrated model runs were conducted for wheat, barley, grain maize, oilseed rape, potato and sugar beet. The WF of cereals could be up to 20 times larger than the WF of tuber and root crops; the largest share was attributed to the green WF. The green and blue WF compared favourably with global benchmark values (R2 = 0.64–0.80; d = 0.91–0.95). The variability in the WF of arable crops across different regions in Europe is mainly due to variability in crop yield (cv = 45%) and to a lesser extent to variability in crop water use (cv = 21%). The WF variability between countries (cv = 14%) is lower than the variability between seasons (cv = 22%) and between crops (cv = 46%). Though modelled yields increased up to 50% under sprinkler irrigation, the water footprint still increased between 1% and 25%. Confronted with drainage and runoff, the grey WF tended to overestimate the contribution of nitrogen to the surface and groundwater. The results showed that the water footprint provides a measurable indicator that may support European water governance.
Authors
Tatsiana EspevigAbstract
No abstract has been registered