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Yield-scaled mitigation of ammonia emission from N fertilization: the Spanish case

Online supplementary data available from stacks.iop.org/ERL/9/125005/mmedia[EN] Synthetic nitrogen (N) fertilizer and field application of livestock manure are the major sources of ammonia (NH3) volatilization. This N loss may decrease crop productivity and subsequent deposition promotes environmental problems associated with soil acidification and eutrophication. Mitigation measures may have associated side effects such as decreased crop productivity (e.g. if N fertilizer application is reduced), or the release of other reactive N compounds (e.g. N2O emissions if manure is incorporated). Here, we present a novel methodology to provide an integrated assessment of the best strategies to abate NH3 from N applications to crops. Using scenario analyses, we assessed the potential of 11 mitigation measures to reduce NH3 volatilization while accounting for their side effects on crop productivity, N use efficiency (NUE) and N surplus (used as an indicator of potential N losses by denitrification/nitrification and NO3 − leaching/run-off). Spain, including its 48 provinces, was selected as a case study as it is the third major producer of agricultural goods in Europe, and also the European country with the highest increase in NH3 emissions from 1990 to 2011. Mitigation scenarios comprised of individual measures and combinations of strategies were evaluated at a country- and regional level. Compared to the reference situation of standard practices for the year 2008, implementation of the most effective region-specific mitigation strategy led to 63% NH3 mitigation at the country level. Implementation of a single strategy for all regions reduced NH3 by 57% at the highest. Strategies that involved combining mitigation measures produced the largest NH3 abatement in all cases, with an 80% reduction in some regions. Among the strategies analyzed, only suppression of urea application combined with manure incorporation and incorporation of N synthetic fertilizers other than urea showed a fully beneficial situation: yieldscaled NH3 emissions were reduced by 82%, N surplus was reduced by 9%, NUE was increased by 19% and yield was around 98% that of the reference situation. This study shows that the adoption of viable measures may provide an opportunity for countries like Spain to meet the international agreements on NH3 mitigation, while maintaining crop yields and increasing NUEThe authors are grateful to the Spanish Ministry of Science and Innovation and the Autonomous Community of Madrid for their economic support through the NEREA project (AGL2012-37815- C05-01, AGL2012-37815-C05-04) and GASPORC (AGL2011-30023-C03) projects. We wish to thank the FIRE (Federation Ile de France de Recherche en Environment, CNRS and UPMC) as well as the Agrisost Project (S2009/AGR-1630). Eduardo Aguilera gratefully acknowledges funding by the 895-2011-1020 project (Canadian Social Sciences and Humanities Research Council). This paper has been produced within the context of the REMEDIA network (http://redremedia.wordpress.com).Sanz-Cobeña, A.; Lassaletta, L.; Estellés, F.; Del Prado, A.; Guardia Guardia, G.; Abalos, D.; Aguilera, E.... (2014). Yield-scaled mitigation of ammonia emission from N fertilization: the Spanish case. Environmental Research Letters. 9(12):1-12. https://doi.org/10.1088/1748-9326/9/12/125005S11291

Impermeable membranes for slab-track settlement mitigation

A series of numerical simulations is used to explore the effect of the geometrical disposition of impermeable membranes in the overall performance of slab-track railway earthworks, with particular reference to the generation of settlement during several years of exposure to the atmosphere and the admissibility of these post-construction deformations according to the available standards. A methodology suitable to account for the effects of rail traffic loading and environmental actions over its service life is presented. To emphasise the effect of the water-impermeable membranes on the atmospheric-induced embankment irreversible deformations, both semi-arid and wet climate conditions were investigated, making use of real climate data for a period of 10 years. The numerical results show that the calculated settlement can be beyond the admissible values and that the use of impermeable membranes is an available alternative for its mitigation.Peer ReviewedPostprint (author's final draft