Determination of best sowing date and cropping architect of corn for forage production as a second crop is important for livestock growers in the western Iran. Therefore this study was conducted by using corn hybrid (KSC 704) at Kermanshah province in two years of 2008-09. The experiment was laid out in split–split plot with three replications. Treatments contain three planting dates of 20th, 30th June and 10th July, three plant density of 80000, 90000 and 100000 plant/ha and three inter row space 55, 65 and 75 cm that arranged as main and subplots respectively. Result showed that there was no significant difference between two sowing years. The highest fresh yield with 82.8 and dry yield with 39.2 ton/ha produced by earliest sowing date (20 June) respectively. Also the highest fresh (77.9 ton/ha) and dry (36.6 ton/ha) yield produced by 65 cm inter row space, while the lowest fresh (74 ton/ha) and dry (34.6 ton/ha) yield achieved by 75 cm inter row space. By increasing plant density from 80000 plant/ha to 90000 plant/ha fresh and dry yield increased but by raising more plant density to 100000 plant/ha fresh and dry yield decreased. Highest amount of NDF (55.4 %) and ADF (34 %) was achieved in planting dates of 20 June and 10 of July, respectively. Also highest NDF (55.5 %) and ADF (35.8 %) was produced in inter row spacing of 75 cm. Plant density of 100000 plant/ha produced highest amount of NDF (56.3 %) and ADF (34.8 %). Delay in planting date reduced forage quantity and quality. Using of higher sowing density resulted in forage quality reduction because of increasing of acid detergent fiber (ADF) and non detergent fiber (NDF) indices.
