Adubação nitrogenada em braquiarão: decomposição da fitomassa e liberação de nutrientes

Resumo

Topdressing or pre-seeding nitrogen (N) application increases phytomass production, providing a higher nutrients accumulation and indirectly favoring the subsequent crop. However, N fertilization can alter the dry matter decomposition and nutrients release dynamics. This study aimed at evaluating the decomposition rate, cellulose, lignin and nutrients release speed from palisadegrass as a function of N fertilization. The experimental design was randomized blocks with four replications, in a factorial scheme constituted by two N fertilization levels and six sampling times after desiccation [0, 14, 34, 41, 51 and 68 days after management (DAM)]. The topdressing N fertilization on palisadegrass increases the dry matter production and N accumulation, but does not alter the decomposition and release speed. N fertilization reduces the C/N ratio, but it does not change the contents of cellulose and lignin and the decomposition and release of N, K, Ca, Mg, C and Si. The amounts of P and S accumulated in the plant and released into the soil increase with N fertilization. The maximum release rates occur within 0-14 DAM, being more intensive for P and S when N is applied. These results demonstrate the high potential of this species for croplivestock integration systems, with some advantages that can be potentialized with higher N doses.

Descrição

Palavras-chave

Urochloa brizantha, Celulose, Lignina, Persistência de palhada, Reciclagem de nutrientes, Cellulose, Lignin, Straw persistence, Nutrients recycling

Citação

COSTA, Claudio Hideo Martins da; CRUSCIOL, Carlos Alexandre Costa; SORATTO, Rogério Peres; FERRARI NETO, Jayme; MORO, Edemar. Adubação nitrogenada em braquiarão:decomposição da fitomassa e liberação de nutrientes. Pesquisa Agropecuária Tropical, Goiânia, v. 46, n. 2, p. 159-168, abr./jun. 2016. Disponível em: <https://www.revistas.ufg.br/pat/article/view/39297/21206>.