In order to evaluate the use of urea nitrogen, the balance of nitrogen (15N)in Brachiaria brizantha pastures was obtained when urea was applied eitherincorporated or in the soil surface (in four applications beginning in Novemberof 1998) and the lime was applied in two periods (March and August of 1998). Therecovery and retention of the N-urea were obtained for each plant structure ofthe soil-pasture system, and indicated that the plant crown is a very importantstorage organ for the N applied via Urea. Liming in March favored forage massproduction and improved the efficiency of N use when urea was incorporated. Theincorporation of urea improved both, the recovery and retention of nitrogen inmost Brachiaria structures. Difference in N recovery between the best (limeapplication in March with urea incorporated) and the worst treatment (liming inMarch with urea-N on the soil-surface) was around 50 kg N.ha-1 afterone year.
