Sugarcane (plant cane) yield and the N utilization of urea applied onto the cultivation was evaluated in a sandy soil with incorporated crop residues (roots, rhizomes, stalks, tops and dry leaves) in a pot experiment (220 L). The studied factors were: N doses (0, 30, 60 and 90 kg ha-1), applied as urea-N labeled with 15N and sugarcane crop residues incorporated in the soil, with and without dry leaves. The design of the experiment was of randomized blocks in three replications, carried out in Piracicaba, São Paulo State, from January to December 1996. Stalk and sugar production increased by the N fertilization, independently of the composition of sugarcane residues incorporated in the soil. Nitrogen fertilization together with incorporated crop residues led to a higher total N accumulation by the plant cane. Independent of the applied urea-N rate, 54 % of N were recovered by the plant, with a percentage of 10 % in rhizomes and roots. Nitrogen fertilization in the cultivation favored the growth of the root system and also increased its reserve of N.
isotope technique; 15N; urea; crop residues