Sources and rates of residual phosphorus for Marandu palisadegrass grown in Western São Paulo

Abstract

The pastures of western São Paulo are grown on low fertility soils, therefore, forage has low nutritional value resulting low dry matter yield (DMY).Thus, phosphorus fertilization and analysis of its residual are important for livestock, as it interferes the development speed of forage grasses, allowing better use of area and helping to pasture maintenance, in addition maintaining DMY at adequate levels. This study aimed at evaluating the effect of sources and rates of phosphorus applied in Marandu palisadegrass (Urochloa brizantha cv. Marandu) maintenance to reduce its seasonality, in order to achieve higher yield of these plants. A randomized block de­sign used with 16 treatments and four replications in a 4 x 4 factorial, consisted of four sources of P (Phosphate from Araxá, Reactive phosphate from Arad, Simple superphosphate and thermophosphate) at rates (0, 100, 200 and 300 kg ha ^-1 of P₂O₅). A total of ten cuts were performed. DMY was quantified and contents of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) were determined and P concentrations of Marandu palisadegrass shoot. The residual of sources and P rates did not influence DMY, CP, NDF and ADF contents and P concentrations of plant tissue, indicating that for maintaining Marandu palisadegrass P levels in soil were sufficient and this forage is not demanding regarding this nutrient.