FONTES E FORMAS DE APLICAÇÃO DE FÓSFORO NA SEGUNDA SAFRA

Abstract

The, the aim of this study was to evaluate the residual effect of phosphorus on intercropping of forage in the off-season. The experimental design was randomized blocks in factorial scheme 4 x 2 + 1 and four sources of phosphorus (Reactive Phosphate Bayóvar - 29% P2O5 total (FR), Monoammonium Phosphate 52% P2O5 (MAP), Single Superphosphate - 18% P2O5 (SS) and the Triple Superphosphate 42% P2O5 (ST)) and two application forms (broadcasted and line), plus an additional treatment without phosphorus fertilization with four blocks. The experiment was carried out in the off-season in area planted with soybean crop in 2014/2015. The source treatments and application forms were applied in soybeans. The residual effect of phosphate fertilizer provided increments in growth and biomass production of forage sorghum especially for phosphorus acidulous sources (SS and ST) applied at broadcast. The lower P content in the tissue of plants fertilized with SS and TS may be attributed to the diluting effect of this nutrient in the plant, as it achieved the highest biomass production. The ST application also favored the dry matter production of piatã grass. In the depth of 0 to 5 cm was higher P content with FR application, but biomass production was low, a factor that may be related to the P linked to Ca overestimation by extractor Mehlich I.