Objective of the study is to determine the effects of different liquid-manure doses and manure-chemical fertilizer combinations on yield and quality parameters of silage corn grown as second crop after vetch + barley combination. Experiments were carried out in randomized block design with 4 replications during the years 2010 and 2011 in Turkey. Totally, 12 treatments consisting of different doses of liquid manure alone and combinations of liquid manure with chemical fertilizers were tested in the experiment. Two year average indicated that green herbage yield, plant height, plant diameter, cob ratio, stem ratio, crude protein ratio, NDF and ADF ratios varied between 35396.7-44610.0 kg ha-1; 193.13-237.07 cm; 13.25-17.30 mm; 30.52-33.75 %; 20.20-24.61 %; 42.45-49.05 %; 3.96-8.46 %; 65.01-69.77 % and 33.51-35.85 %, respectively. Research results showed that 15 ton liquid manure + 30 kg ha-1 chemical nitrogen combination (L1.5N3) had higher green herbage yield (44610.0 kg ha-1) than 120 kg ha-1 chemical nitrogen treatment (N12). However, crude protein ratio of N12 treatment (8.46 %) was higher than L1.5N3 (5.55 %) and the difference between them was found to be significant. The first study on sustainable second crop silage maize production under Central Anatolian highlands conditions demonstrated that chemical nitrogen use can significantly be reduced by using liquid manure as an alternative to chemical fertilizers without any negative effects on soil chemical characteristics.