2017-11-302017-11-302003-06KLIEMANN, Huberto José; MAGALHÃES, Roberto Toledo de; OLIVEIRA, Itamar Pereira de; MORAES, Milton Ferreira de. Relações da produção de massa verde de Brachiaria brizantha com os índices de disponibilidade de nutrientes em solos sob o sistema barreirão de manejo. Pesquisa Agropecuária Tropical, Goiânia, v. 33, n. 1, p. 49-56, jan./jun. 2003. Disponível em: <https://www.revistas.ufg.br/pat/article/view/2400>.1517-6398http://repositorio.bc.ufg.br/handle/ri/13058Relations of green matter yield to nutrient availability in a dystrophic Oxisol (Goiás, Brazil) were assessed in a pasture area derived from an original savannah opening. Pasture was established by applying 1.5 t ha-1 of calcitic lime and direct sowing of Brachiaria decumbens. After ten years, this pasture was replanted using the Barreirão system. In a single operation, rice and Brachiaria brizantha were sown together and fertilizers were applied at depths of 3-5 cm and 8-10 cm, respectively. Areas where the system had been ineffect for one to six years were monitored, using a native forest area and another with 17-year old traditional pasture as reference. The data obtained allow to conclude the following: i) a critical level of 19.5g OM kg-1 of soil was estimated by relating green matter yield to organic matter contents in the soils, but this is not a reliable index for available nitrogen, because of the dynamic character of soil organic matter; ii) critical levels for nutrients in soils were determined for: exchangeable calcium + magnesium – 4.5 cmolc dm-3; exchangeable potassium – 123 mg dm-3; available zinc – 1.7 mg dm-3; available copper – 2.2 mg dm-3; iii) no critical level for available phosphorus has been established, because the applied rates were insuffi-cient to sustain productivity through the years.porAcesso AbertoCerradoMacronutrienteMicronutrientePastagens tropicaisMacronutrientMicronutrienTropical pasturesArtigo