Lodos de esgoto alcalinizados em solos do estado do Paraná: taxa de aplica o máxima anual e compara o entre métodos para recomenda o agrícola Alkaline sewage sludge on soils of Paraná state: maximum annual application rate and comparison between methods for agricultural recommendation

Para o uso agrícola do lodo de esgoto higienizado por processo de estabiliza o alcalina prolongada (lodo EAP), além de estabelecer limites de aplica o máxima conforme a legisla o, é necessário estudar atributos dos lodos e dos solos que favore am as metodologias de sua recomenda o. Objetivou-se determinar a taxa de aplica o máxima anual (TAMA) de lodo EAP pelo critério de eleva o do pH para 20 lodos e solos do estado do Paraná; determinar a influência dos atributos desses solos nos valores da TAMA de lodo EAP; avaliar o uso dos métodos de satura o por bases (V%) e pH referência (SMP), utilizando como padr o o método da incuba o. Empregou-se o ensaio de incuba o para lodo EAP aplicado ao solo, conforme metodologia oficial. Os resultados indicam que as TAMA de lodo EAP variaram de 10 a >80 Mg.ha-1 para as 20 regionais estudadas; Os atributos químicos (capacidade de troca de cátions, H+Al e carbono) e físico (argila) s o os que melhor definem a determina o da TAMA, apresentando rela o diretamente proporcional. Os métodos do V% e do pH referência (SMP) para pH H2O 5,5 mostraram-se seguros quanto à recomenda o agrícola. For agricultural use of alkalinized sludge (AS), beyond to establish the maximum application limits to comply with the legislation, it is necessary to study the attributes of sludges and soils that favor the methodologies of its recommendation. The objectives of this study were to determine the maximum annual application rate (MAAR) of alkalinized sludge (AS) according to the pH elevation criterion for 20 sludge origins and soils of the Paraná state; to determine the influence of soil attributes over the MAAR of AS; to evaluate two methods rate calculation for AS, the base saturation (V%) and pH reference (SMP) by comparing with the standard incubation methodology for AS sludge application. It was used incubation test for AS applied to soil, following official methodology. The results indicated that the MAAR were ranged 10 to >80 Mg.ha-1, for the 20 regions; the chemical properties (cation exchange capacity, H+Al and carbon) and physical properties (clay) were the best parameters to the determination of the MAAR, showing direct relationship; the V% and SMP (pH H2O 5,5) methods were safe to the agricultural recommendation.