Data/hora: 06/06/2024 02:35:30

Biblioteca(s): | Embrapa Cerrados.
Data corrente: | 22/10/2001
Data da última atualização: | 22/10/2001
Autoria: | KANDA, K.; TAKAHASHI, M.; MIRANDA, C. H. B.
Título: | Nitrogen cycling agropastoral systems
Ano de publicação: | 2001
Fonte/Imprenta: | In: KANNO, T.; MACEDO, M.C.M., ed. JIRCAS / EMBRAPA gado de corte international joint workshop on agropastoral system in South America. [Tsukuba]: JIRCAS, 2001.
Páginas: | p.75-84.
Série: | (JIRCAS Working Report, 19).
Idioma: | Inglês
Notas: | EMBRAPA-CNPGC and JIRCAS joint International Workshop on Agropastoral System in South America, held in Campo Grande, MS, Brazil, 1999.
Conteúdo: | Agropastoral systems that combine soybeans and grass in a crop rotation have been proposed for sustaining grassland productivity in the low fertility soils of Brazilian Cerrados. We studied the nitrogen flow under an agropastoral system established in 1993 a Purple Red Latossol in Campo Grande, MS. Surface soil was collected from fields with continuous soybean cropping (6 years), soybeans cropped after 4 years of grassland, continuous grassland (6 years), grassland planted after 4 years of soybean cropping, a degraded grassland, and na original forest,; the samples were analyzed for N mineralization potential in the soil under the grasslands. The rate of N fixation in the soybeans was determined according to the N-difference method using a non-nodulating isoline, T201, as a control. The determined rate varied from 20 to about 50% of the total plant N. Most of the plant N  was harvested out with the grains, leaving a negative N balance in the field.It was determined that the amount of N entering the system through rain water was small. Nitrate accumulated from the surface to a depth of 100 cm in the soil under the soybeans, indicating a potential leachingof nitrate. The estimated amount of leaching from the soybean fields, whereas there was large compared with that from the grasslands. A large negative N balance was measured in the soybean fields, whereas there was a small negative N balance in the grassland fields.
Palavras-Chave: | Agropastoral systems; Ciclagem; Cycling; Sistema agropastoril.
Thesagro: | Cerrado; Nitrogênio.
Thesaurus Nal: | nitrogen.
Categoria do assunto: | --
Registro original: | Embrapa Cerrados (CPAC)
Exemplares: | CPAC - (12390-1) - ADD - PL - -- - CRI5532 -  - CRI5532 - DIS