A "tabuleiro" soil, from Rio Largo, State of Alagoas, Brazil, was used. The experiment took place at the Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, located in Piracicaba, State of São Paulo, Brasil. Corn plant (Zea mays L.) c.v. Piranão was used as test plant. The evaluation parameters were production of dry matter. In what concerns to the dry matter production, ammonium nitrate surpassed all the others in the rate of 120 kg N/ha. In a general way the rate of 240 kg N/ha was excessive and injurious.