Caracteristicas Quimicas De Solo Sob Pastagens Degradadas De Brachiaria Brizantha Cv Marandu.

TitleCaracteristicas Quimicas De Solo Sob Pastagens Degradadas De Brachiaria Brizantha Cv Marandu.
Publication TypeJournal Article
Year of Publication2003
AuthorsTownsend CR, Costa NL, Magalhaes JA
JournalPasturas Tropicales
Keywordsbrizantha cv. Marandu, Fertilizer, Phosphorus, potassium
AbstractThe effect of the application of lime and fertilizers (N, P, K) on the rehabilitation of a degraded pasture of Brachiaria brizantha cv. Marandu, grown on a dystrophic Yellow Latosol of clayey texture, was studied under field conditions at the Empresa Brasileira de Pesquisa Agropecuária (Embrapa-Rondônia) in Porto Velho, Brazil, over a 3-year period. A randomized block design was used, arranged in a 2 x 2 x 2 x 2 factorial for levels of liming (base saturation of 20% and 40%) and doses of nitrogen (50 and 100 kg N/ha as urea), phosphorus (50 and 100 kg P2O5/ha as triple superphosphate) and potassium (30 and 60 kg K2O /ha as potassium chloride) and in a 3 x 2 x 2 x 2 factorial for fertilization frequencies (annual, biennial, and triennial) and levels. The lime and fertilizers were applied after native vegetation was controlled and light plowing. Soil samples were taken at a depth of 0-15 cm and 15-30 cm to determine the effect of the treatments on soil physical properties. Cations and exchangeable Al decreased significantly, while soil pH and exchangeable bases increased. At both depths, total P increased with the P doses applied fractionated every 2 years. When lime was applied to correct bases up to 20%, the best responses to P in samples taken between 0 and 15 cm were found when 60 kg K2O /ha were applied, which did not occur at 40% base saturation. Treatments did not affect K or OM contents. P content was only affected by frequency of application. Under these study conditions, it is recommended that lime be applied to increase base content to 40% and NPK fertilization rates of 100, 50, and 60 kg/ha at a minimum frequency of 2 years.