02315naa a2200253 a 450000100080000000500110000800800410001910000210006024501070008126000090018852015120019765000150170965000110172465000250173565000200176065000200178065300150180065300110181565300200182665300120184670000230185870000230188177301570190410571522000-02-25       1993    bl ---       0--  u    #d1 aMACEDO, M. C. M.  aSeasonal changes in the chemical composition of cultivated tropical grasses in the savannas of Brazil.  c1993  aFive tropical grasses; Brachiaria brizantha cv. Marandu, B. decumbens cv. Basilisk, Panicum maximum cv. Coloniao, P. maximum cv. Tobiata, P. maximum cv. Tanzania-1, were planted on a dark red latosol (Oxisol) and grazed for 3 rainy and 3 dry seasons. The original savanna vegetation was removed, the soil cultivated and fertilised with 1000 Kg/ha of dolomitic limestone, 350 Kg/ha of single superphosphate, 100 Kg/ha of KCL and 40 Kg/ha of fritted traced elements. Treatments were arranged in a RCB design with 3 replicates. Paddocks were 1.5 ha. Grazing pressure was adjusted to approximately 8 or 15 Kg of total dry matter (DM) of pasture on offer/100 Kg of live weight in Panicum cultivars and Brachiaria species, respectively. Plant samples were collected monthly simulating animal grazing (plucked by hand). Nutrient concentration of N, P, K, Ca, MG and S were analysed on a DM basis. General trends showed decreasing plant tissue concentration of all elements in the 5 species with the exception of Ca and Mg, Which had a slight increase with time. Phosphorus content was the most significant parameter associated with green DM (leaf+stem) which in turn was the best predictor of animal daily gain. Panicum cultivars were more sensitive to phosphorus decline (1.83-0.93 g/Kg) than Brachiaria species (1.45-1.00 g/Kg). Nutrient concentrations were highly associated with rainfall pattern, and maximum level of most elements occurred, regardless of year, 30-40 days after the start of the opening rains.  aacid soils  aBrazil  aBrachiaria Brizantha  aPanicum Maximum  aValor Nutritivo  aBraquiaria  aBrasil  aMacronutrientes  aSavanna1 aEUCLIDES, V. P. B.1 aOLIVEIRA, M. P. de  tIn: INTERNATIONAL GRASSLAND CONGRESS, 17. 1993. Palmerston North. Proceedings...Palmerston North: New Zealand Grassland Association, 1993. p .2000-2002.