The organic fertilizer can be a viable alternative in the production of forage grasses, however there is little information regarding doses and composition of the major organic fertilizers. The aim of this paper was to verify the influence of the different doses of organic compost produced from two types of poultry litter on the structural, morphogenetic and productive characteristics of Brachiaria brizantha cv 'Piatã'. The experiment was conducted in a greenhouse in a completely randomized design in a factorial scheme l with parcel subdivided in time. The parcels were composed by six treatments: two types of compost (poultry litter based in sugar cane and napier grass) in three doses (100, 200 and 300kg ha-1 equivalent N.) and the subparcels by the four different periods of cut. The composts were applied in a unique dose, after the uniformization cut, at the quantities: 11,36 and 11,83, 22,73 and 23,67, 34,09 and 35,50 g pot-1 for the poultry litter based in sugar cane and napier grass, respectively which are equivalent to the rates of 0, 100, 200 and 300kg ha-1 of N. The variables measured were: dry matter production (DMP), leaf appearance rate (LApR), phyllochron, leaf elongation dose (LER) and shoots elongation rate (SER), number of green leaves (NGL), final size of the leaf (FSL). No significant difference between the types of composts and in the interaction compost x doses was observed, thus, both could be used without the risk of loss in the use of the nutrients by the plants evaluated in the experiment. There was a significant difference between the DMP, LApR, phyllochron, LER, SER, NGL and FSL because of the increasing rates of nitrogen, followed by a linear model of prediction. The effect of the periods of slaughter was also observed, where the slaughters carried out in the summer presented a better performance over the morphogenetic and structural features evaluated.
Brachiaria brizantha; phyllochron; dry matter; nitrogen
