A study was conducted to determine the optimal level of nitrogen for a better performance of the virgin canes. The vegetal materiel is composed of the variety SP 70-1284. The materiel of laboratory is composed of an electric grinder ("Jeffco" food and fodder cutter grinder, model 265 B, set L 1710), a refractometer (Schmidt+Haensch, HARD-SW model, set 29129) and a polarimeter (Saccharomat Z, set 29305). The test was conducted with the variety SP 70-1284 as an experimental randomized complete block with 9 treatments, with 4 repetitions. The total doses of N of three contributions for the cycle of harvest (