Data/hora: 11/06/2024 14:30:52

Biblioteca(s): | Embrapa Gado de Corte.
Data corrente: | 05/11/2001
Data da última atualização: | 05/11/2001
Autoria: | KANDA, K.; TAKAHSHI, M.; MIRANDA, C. H. B.
Afiliação: | Japan International Research Center for Agricultural Sciences (JIRCAS).
Título: | Nitrogen flow in agropastoral systems, Brazil.
Ano de publicação: | 2001
Fonte/Imprenta: | JIRCAS Journal, Isukuba, n.9, p.23-31, mar. 2001.
Idioma: | Inglês
Notas: | CNPGC.
Conteúdo: | Agropastoral systems that combine soybean and grasses in a crop rotation have been proposed for sustaining grassland productivity in the low-fertility soils of the Brazilian savanna. We studied the nitrogen flow under an agro-pastoral system developed in 1993 in a Purple Red Latosol in Campo Grande, MS. Four cropping  systems were included: continuous soybean cropping, soybean cropping after 4 years of grass cultivation. continuous grass cultivation, grass cultivation after 4 years of soybean cropping. The rate of  N fixation in soybean was determined by the N difference method and 15N natural abundance method. A  non-modulating isoline, T201, was used as a control in both methods. The rate of N2 fixation rangel from 23 to 51% of the total plant N. The amount of N taken out as grains was larger than the amount of fixed N in soybean. the amount of entering the system through rainwater was 6 kgN/ha/yr. Nitrato accumulating in soil from the surface to a deph of 100 cm under soybeans  indicated the potential leaching of nitrate. The estimated  amount of nitrate leaching from the soybean fields was large compared with that from the grasslands. A large negative N balance of 134-211 kgN/ha/yr was estimated in the  soybean fields, whereas the N balance in the grasslands was a sligtly negative.
Palavras-Chave: | Agropastoral systems; Basilisk; Brasil; Brazilian savannas; Campo Grande; Integracao agricultura pecuaria; Mato Grosso do Sul.
Thesagro: | Brachiaria Decumbens; Cerrado; Nitrogênio; Panicum Maximum; Pastagem; Soja.
Thesaurus Nal: | Brazil; nitrogen; pastures; soybeans.
Categoria do assunto: | --
Registro original: | Embrapa Gado de Corte (CNPGC)
Exemplares: | CNPGC - (8877-1) - UPC - AP - -- - 630.5 -  - 630.5 - DIS