Besides the use of high doses of nitrogen fertilizer, the intensive management of tropical pastures, have advocated smaller rest periods and higher intensities of defoliation in order to ensure better canopy structure. However, after defoliation the plant need to adjust your energy balance to meet the demands for shoot and root recovery. The objective was to evaluate the effect of five doses of nitrogen, two application times and two stubble heights on the production of BRS Zuri; a new Panicum maximum cultivar. The two application times evaluated were: immediately after cutting (AC) and after the emergence of the first fully expanded leaf (AFL). The two stubbles heights used were 15 and 30 cm. Nitrogen rates were 0, 20, 40, 60 and 80 mg/dm³ of soil. The trial was conducted in pots in a 5x2x2 factorial scheme. The experimental design was a complete randomized with three replications. Data were analyzed using the Mixed Procedure of SAS® and means were estimated using the "LSMEANS" command and comparisons made with “Tukey” test with a 5% significance level. The forage in the pots was harvested after 30 days of regrowth. At the time of cutting the average root mass was 1.8g. One week after cutting the root mass decreased (1.5g) for the 15 cm of stubble height treatment while it was stable for the 30 cm stubble height (1.9g). At 14 days after cutting the root mass increased to 3.1g for the stubble height of 15cm and to 5.1g for the 30 cm stubble height. Despite that greater harvested forage mass was observed in the residue 15 cm (14.5 x 11.2g/plot). The nitrogen application time only affected the SPAD chlorophyll content, higher in AFL treatment (25.5 X 23.5). Nitrogen doses influence all variables. The plant height and number of tillers increased linearly with doses of nitrogen, while the SPAD chlorophyll content and harvested forage mass showed a quadratic increase to the doses. Financial: Fapemig

Keywords: nitrogen application time, nitrogen doses, forage mass, root mass, stubble height