Morfogênese do Capim Massai sob Lotação Rotativa com Ovinos e o Efeito da Adubação Fosfatada e Nitrogenada em Solo Arenoso

Abstract

The objective of this study was to evaluate the effects of two doses of phosphate fertilization (50 e 200 kg . ha-1 P2O5) and two doses of nitrogen fertilization (100 e 400 kg . ha-1 N) in a randomized block design in factorial scheme 2x2+1, with one additional treatment (control), on the morphogenic and structural aspects of the Panicum maximum cv. Massai. The treatments were implanted in the experimental area using simple superphosphate for phosphate fertilization and ammonium sulfate for nitrogen fertilization. Samples were collected at a height of 15 cm from the soil, in three cycles pre and post grazing in the grazing system rotated with 4 days of occupation and 28 days of rest. The morphogenesis was evaluated by the marked tillers. It was evaluated the rate of leaf emergence (TApF); leaf elongation rate (TAlF); leaf senescence rate (TSF); And stem elongation rate (TAlC). There was difference between the control treatment and other treatments, and effect of the interaction of the fertilizations on the TAlF, with the best dose response (100 kg . ha-1 de N e 50 kg . ha-1 P2O5) Introducing 43,85 mm . tillers-1 . day-1 . The TAlC and TSF were not affected by the fertilization interactions studied, there was also no difference when compared to the control treatment. For TApF, the doses (400 kg . ha-1 N e 200 kg . ha-1 P2O5) that affected the appearance of new leaves. There was no difference or interaction of the treatments on the number of tillers (NP). High doses of nitrogen influenced the leaf life span (DVF). The phosphate and nitrogen fertilization influenced the morphogenic variables of the Massai grass. Nitrogen acts in the process of forage growth and development, while phosphate fertilization alone has no significant effect.