Nitrate leaching from a Latosol after application of liquid swine manures in different pH values and organic matter contents/Lixiviacao de nitrato em Latossolo apos aplicacao de dejetos liquidos de suinos com diferentes valores de pH e teores de materia organica

Liquid swine manures are produced in large volumes in the western Parana and Santa Catarina states and are reused as a source of nutrients. This study aimed to evaluate the losses of nitrate (N-N[O.sub.3.sup.-1]) after application of liquid swine manures in three samples of a Latosol (Rhodic Eutrudox) with different levels of soil organic matter and pH collected at different depths. The experimental design was completely randomized with one soil, three levels of soil organic matter (34.09, 22.36 and 8.6 g [dm.sup.-3]), four pH in Ca[Cl.sub.2] (4.0, 5.0, 6.0 and 7.0) conditions and three replications. Each experimental unit contained 450 [cm.sup.3] of soil that received a dose of liquid swine manures equivalent to 120,000 [dm.sup.-3] [ha.sup.-1]. The concentration of N-N[O.sub.3.sup.-1] was evaluated in the leaching solution after the weekly application of water equivalent to 150 mm for a period of 35 days. The amount of (N-N[O.sub.3.sup.-1]) leached increased with soil organic matter content and soil pH. The amount of nitrate leached tends to be maximum at pH close to or above 7.0. Key words: animal wastes, anion exchange capacity, nitrogen, swine manure. Dejetos liquidos de suinos sao produzidos em grandes volumes no oeste dos Estados do Parana e Santa Catarina e reutilizados como fonte de nutrientes. Este trabalho teve por objetivo avaliar as perdas de (N-N[O.sub.3.sup.-1]) apos aplicacao de dejetos liquidos de suinos em tres amostras de um Latossolo Vermelho eutroferrico com diferentes teores de materia organica e valores de pH, coletadas em diferentes profundidades. O delineamento experimental utilizado foi o completamento casualizado com um solo, tres teores de materia organica (34,09; 22,36 e 8,6 g [dm.sup.-3]), quatro niveis de pH em Ca[Cl.sub.2] (4,0; 5,0; 6,0 e 7,0) e tres repeticoes. Cada unidade experimental continha 450 [cm.sup.3] de solo que recebeu uma dose de DLS equivalente a 120.000 [dm.sup.-3] [ha.sup.-1]. Avaliou-se a concentracao de nitrato (N-N[O.sub.3.sup.- 1]) na solucao lixiviada apos a aplicacao, semanalmente, de uma lamina de agua equivalente a precipitacao de 150 mm, por um periodo de 35 dias. As quantidades de (N-N[O.sub.3.sup.-1]) lixiviadas aumentaram com o teor de materia organica e com o pH do solo. A quantidade de nitrato lixiviado tende ser maxima em valores de pH proximos ou acima de 7,0. Palavras chave: residuos organicos, capacidade de troca anionica, nitrogenio, residuos de suinos.