Manure has not been evaluated as an N source for maize (Zea mays L.) production underidge tillage (RT). A 2‐yr field study was conducted on a Kendaia‐Lima silt loam (fine‐loamy, mixed, nonacid, mesic Aeric Haplaquept) to evaluate growth, yield, and quality of forage maize under moldboard plow (MP) and RT with fertilizer N (MPF and RTF) or with manure and supplemental fertilizer N (MPM and RTM, respectively). Soil water pressure and leaf carbon exchange rates (CER) were measured frequently; and plant N concentration, leaf area index (LAI), and dry matter (DM) accumulation were sured at the six‐leaf stage (V6), silking (R1), and harvest. The treatment generally had lower CER from V5 to V8, lower whole‐plant N concentrations at V6 in 1989 (24.7 g kg−1) and 1990 (28.2 g kg−1), and lower LAI and DM accumulation at V6 (0.39 and 37 gm−2) and R1 (3.27 and 844 gm−2, respectively) in 1989. In contrast, RTM compared to MPF and RTF had similar CER, whole‐plant N concentrations, LAI and DM accumulation on most measurement dates. The MPM treatment compared to MPF, RTF, and RTM had lower DM yields (13.6, 16.3, 15.7, and 14.9 Mg ha−1) and whole‐plant N concentrations (7.8, 8.5, 8.5, and 8.4 g kg−1) in 1989, and lower DM yields (13.7, 15.3, 15.0, and 15.9 Mg ha−1, respectively) in 1990. Surface application of manure before planting with supplemental fertilizer N at V5 was a viable N management system for forage maize under RT.