It was carried out an experiment to test four levels of soil base saturation (20, 40, 60, and 80%), four rates of phosphorus (0, 80, 160, and 240 kg/ha of P2O5) and four rates of nitrogen (0, 100, 200 and 300 kg/ha) during the phase of establishment of Panicum maximum cv Massai, in an Oxisol of Brazilian Cerrado. The experimental design was a randomized uncompleted block, in fractionated factorial type (1/2)4³, with four blocks and two replications. Two cuts along 200 days were performed. The evaluated aspects were green dry matter yield (GDM), soil fertility changes, concentration of macronutrients in diagnostic leaves, crude protein (CP) concentration and in vitro organic matter digestibility (IVOMD). It was verified that GDM yield responded mainly to phosphorus (P) fertilization and, in second place, to soil base saturation (V). The nitrogen (N) did not present significant effect in GDM yield. The P rate for highest physical yield was 237 kg/ha and the economical rate was 185 kg/ha, both in 39% of V in the soil. Soil fertility improved with the V and P increment. The concentration of macronutrients in diagnostic leaves increased with the increment of V, P, and N. It was verified high percentage of leaves in GDM and suitable IVOMD and CP concentration in the GDM of leaves. IVOMD and CP increased significantly with N fertilization and increment of V.
diagnostic leaves; green dry matter; Oxisol; Panicum maximum
