Composição Mineral das Pastagens das Regiões Norte e Noroeste do Estado do Rio de Janeiro. 2. Manganês, Ferro, Zinco, Cobre, Cobalto, Molibdênio e Chumbo

Abstract

The contents of Mn, Fe, Zn, Cu, Co, Mo and Pb of soil, predominant forage in the pastures and water, were studied in the North and Northwest regions of Rio de Janeiro State, during the dry (June-July) and rainy (December-January) seasons. Samples of soil, forage and water were collected in 12 different points of the regions, in predominant grazing areas, as determined by satellite photograph and according to different soil characteristics. The mineral contents of the sample extracts were determined by spectrometry, on a inductive plasma emission source apparatus. In both seasons it was found low levels of Cu and Zn in forage samples and the mineral contents of forages varied with the type of soil. The levels of Fe and Mn were higher than the requirements and deficiencies of Cu and Zn were found. The cobalt contents of forages were higher than cattle requirements. The analyzed microelements in water usually were very low when compared with the safety levels. It was concluded that the mineral contents in the water analyzed samples were within the safety margin for domestic animals.