Brazilian Journal of Agriculture v.93, n.3, p. 313 – 323, 2018 313 SOIL MINERAL NITROGEN IN SOIL UNDER INJECTION AND SURFACE APPLICATION OF SWINE SLURRY WITH NITRIFICATION INHIBITOR Luiz Paulo Rauber 1 , Andréia Patrícia Andrade 1 , Álvaro Luiz Mafra 1 , Walter Santos Borges Júnior 1 , Daniel João Dall’Orsoletta 1 , Luciano Colpo Gatiboni 1 , Celso Aita 2 1 Universidade do Estado de Santa Catarina. E-mail: sr_roiber@yahoo.com.br; andreiapatricia74@yahoo.com.br; alvaro.mafra@udesc.br; waltersbjr@hotmail.com; dani.orsoletta@gmail.com; lgatiboni@gmail.com 2 Universidade Federal de Santa Maria. E-mail: celsoaita@gmail.com ABSTRACT Management alternatives can minimize the negative impacts of swine slurry (SS) on the environment and improve its fertilizing effect. The objective of this study was to evaluate the application of SS and urea, associated with nitrification inhibitor dicyandiamide (DCD), on mineral N contents in no-tillage soil. The experiment was carried out on a Humic Dystrupept soil, in a randomized experimental block design with four replications, using a 2 x 5 factorial. The treatments were as follows: injected and surface SS application and urea and five sources of N, urea; urea + DCD; SS; SS + DCD and a control treatment with no N. The evaluation of ammonium and nitrate occurred during the maize crop seasons 2012/2013 and 2013/2014 and during the wheat crop in 2013, with soil sampling at depths of 0-5, 5-10 and 10-20 cm. The injected application of SS + DCD increased the ammonium content by 65% compared to the surface application, at eight days in the 2012/2013 crop, preserving for longer the N in the ammoniac form. DCD use and the injection of both fertilizers were efficient in maintaining the ammonium for a longer period in the soil. Keywords: Manure, fertilization, ammoniacal-N, losses of N NITROGÊNIO MINERAL NO SOLO COM APLICAÇÃO INJETADA E SUPERFICIAL DE DEJETO DE SUÍNOS COM INIBIDOR DE NITRIFICAÇÃO RESUMO Alternativas de gerenciamento podem minimizar os impactos negativos da aplicação de dejetos líquidos de suínos (DLS) no meio ambiente e melhorar seu efeito fertilizante. O objetivo deste estudo foi avaliar a aplicação de DLS e ureia, associada à inibição da nitrificação diciandiamida (DCD), no conteúdo de N mineral em solo sem plantio direto. O experimento foi realizado em um Cambissolo