Parcelamento da adubação nitrogenada em cana-planta no norte do Estado do Rio de Janeiro

Two experiments were conducted to study the effect of forms of N application (split vs. single) in sugarcane (plant cane). Two soil types were used: a cambisol (Inceptisol) and a podzolic-lactosol (ultisol). The duration of the experiment was from March/83 to July/84 for the cambisol and from February/83 to August/84 for the podzolic-latosol. The treatments used were A: 0 kg N/ha; B: 180 kg N/ha as a single application at planting; C: 60 kg N/ha at planting and 120 kg/ha broadcasted four months after planting; and D: 60 kg N/ha, applied four months after planting +120 kg N/ha, applied eight months after planting. The sugarcane variety used was CB45-3. During the growth period five samples of soil and plants were taken to evaluate sugarcane yield, soil NO 3 -N and NH 4 -N levels, total-N percentage in the plant, leaf amino-N content, and number of shoots. Response to N fertilizer was observed only in the cambisol soil, and the effect on number of shoots and yield was more evident when N was applied at planting. The result indicated that sugarcane accumulated N in the plant tissues (stalk+leaves) during the initial growth stage