The effects of pasture (Panicum maximum) on the chemical composition of the soil after clearing and burning a typical tropical highland rain forest.

• Autor(a) principal: BAENA, A. R. C.
• Data de Publicação: 1977
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/401751
• topic: Roçagem; Queima; Conteúdo mineral; Manejo de pastagem; Tropical rain forest; Soil testing; Land clearing; Management; Análise do Solo; Conservação do Solo; Floresta Tropical Úmida; burning; mineral content; pastures; soil conservation

Large areas of rain forest in the Amazon Basin, Brazil, are being developed for pasture production. Knowledge is needed as to the effect on soil properties of changing from forest to grass. This knowledge should help in predicting the long-time productivity of the pasture. At "Fazenda Piquia" Paragominas State od Para, Brazil, soil profile samples were collected under forest, on freshly burned leand and on land that hat in pasture for 2, 6, and 10 years. Pasture consist of Guinea grass (Panicum maximum). Pastures were grazed in a rotating grassing system and were burned anuallly. Rainfall averages 2591 mm annually with 80% of the annual total falling in the six-month period december through may. There are sinificant differences in soil texture and in cation exchange capacity, the most stable of soil propertities measeured. These differences indiate that there are mesurable differences between soils at the different sites and thus that other soil diferences may be due to original soil differences as well as or in placa of differences caused by treatment differences. However, all profiles are medium textures oxisol and the exchange capacity determinations indicate that all clays are of kaoliinitic types. among samples all exchangeable bases measurder. Ca, Mg, and K, are lowest in the forest soil and are higher in the samples from the burned area from all the pastures. Land that has been in pasture for 10 years has as much bases in the surface as the recently cleaned and burned land.