Residue of Phosphorus Sources Broadcast and Applied on Rows in Forages during Off-Season Crops

This study aimed to evaluate the residual effect of phosphorus sources and application techniques in the intercropping of forages during off-season crops. The experimental design was randomized blocks in a 4 × 2 + 1 factorial, being four sources of phosphorus [Bayovar Reactive Phosphate (BRP), Monoammonium Phosphate (MAP), Simple Superphosphate (SS) and Triple Superphosphate (TS)], two application techniques (broadcasting and on rows) and an additional without phosphorus. The experiment was conducted during the off-season crop. The residual effect of phosphorus fertilization increased the growth and the production of biomass of forage sorghum regarding broadcast SS and TS sources. The lowest P contents in the tissue of plants fertilized with SS and TS may be attributed to the diluting effect, as it achieved the highest production of biomass. The application of TS favored a greater dry matter production in Brachiaria brizantha cv. Piata. At the depth 0.00-0.05 m, there was a higher P content with the application of BRP. However, the production of biomass was low, a factor that may be related to an overestimation of P bound to Ca by the Mehlich-1 extractor. Under cultivation conditions, broadcast SS and TS had a higher residual effect.