Research Paper Effects of a urease inhibitor and aluminium chloride alone or combined with a nitrification inhibitor on gaseous N emissions following soil application of cattle urine Jose ´ Pereira a,b, *, Arlete S. Barneze c , Tom H. Misselbrook d , Joa ˜ o Coutinho e , Nuno Moreira b , Henrique Trindade b a Agricultural Polytechnic School of Viseu, Instituto Polite ´cnico de Viseu, Quinta da Alagoa, 3500-606 Viseu, Portugal b CITAB - Centre for the Research and Technology of Agro-Environment and Biological Sciences, Department of Agronomy, Universidade de Tra ´s-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal c Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de Sa ˜o Paulo, Avenida Pa ´dua Dias 11, Piracicaba, SP CEP 13418-900, Brazil d Rothamsted Research, North Wyke, Okehampton, Devon EX20 2SB, United Kingdom e Chemistry Centre, Department of Biology and Environment, Universidade de Tra ´s-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal article info Article history: Received 26 January 2012 Received in revised form 29 April 2013 Accepted 7 May 2013 Published online 14 June 2013 Addition to soil of separated cattle-urine obtained from housing with urine-faeces segre- gation systems is an important source of gaseous nitrogen (N) emissions. This study aimed to evaluate the effect of adding different concentrations of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and aluminium chloride (AlCl 3 ), alone or combined with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), on gaseous N losses and N transformations in soil amended with cattle-urine. Using laboratory incubations soil was amended with cattle-urine (200 kg total N ha 1 ) containing NBPT (0.1 or 1.0%) or AlCl 3 (0.5 or 1.0%) either as a single additive or combined with 0.5% DMPP. Three additional treatments were included: soil only (Control), soil amended only with cattle-urine and soil amended with cattle-urine and DMPP. The addition of NBPT at 1% significantly delayed urea hydrolysis during the first 4- d after urine application comparatively to treatments receiving AlCl 3 . Nitrification was inhibited by addition of DMPP, with no further effect (P > 0.05) when DMPP was combined with NBPT or AlCl 3 . The AlCl 3 treatment had no effect on urea hydrolysis or nitrification. The combination of DMPP with NBPT or AlCl 3 increased (P < 0.05) NH 3 emissions and reduced (P < 0.05) NO and N 2 O emissions compared with urine alone. It was concluded that NBPT was more effective at reducing gaseous N emissions from cattle-urine applications than AlCl 3 , and that NBPT alone was more effective than NBPT combined with DMPP. No advantages were gained from the combination of one of these additives with DMPP on total gaseous N emissions. ª 2013 IAgrE. Published by Elsevier Ltd. All rights reserved. * Corresponding author. Agricultural Polytechnic School of Viseu, Instituto Polite ´ cnico de Viseu, Quinta da Alagoa, 3500-606 Viseu, Portugal. Tel.: þ351 232 446 600; fax: þ351 232 426 536. E-mail addresses: jlpereira@esav.ipv.pt, jlpereira@engenheiros.pt (J. Pereira). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/issn/15375110 biosystems engineering 115 (2013) 396 e407 1537-5110/$ e see front matter ª 2013 IAgrE. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biosystemseng.2013.05.002