Nitrogen fertilization on sorghum intercropped with grass in a no-tillage system

The objective of this work was to evaluate the effect of nitrogen fertilization management on single and intercropped sorghum with Marandu and Mombaca grasses, and to determine the forage dry weight yield in the 2003/2004 and 2004/2005, in a no-tillage system. The experimental design was in randomized block, in a 3x5 factorial arrangement, with four replicates. The treatments consisted of three sorghum cropping systems (single and intercropped with Marandu and Mombaca grasses in the rows) and five nitrogen fertilizer managements: 30-70; 70-30; 50-50; 100-0; and 0-100 kg ha(-1) of N, applied at sowing and topdressing, respectively. Intercropping did not affect sorghum nutrition nor grain yield. Only in the first growth season, the 50-50 kg ha(-1) of N splitting increased grain yield. Straw management interfered in sorghum establishment during the second growth season and decreased grain yield. The highest rates of N topdressing increased forage dry weight yield of Marandu grass and, applied at sowing, N highest rates increased this attribute in Mombaca grass.