Determining of Suitable sowing Date for Different Corn hybrids in Rice Rotation system

This experiment has been conducted at Mazandaran Agricultural Research center based in Gharakheil in Ghaemshahr in the crop year 1389 as complete blocks located in 4 replications. Sowing dates at 4 levels 24 July، 2، 12، 23 th August were the major factor and 3 corn hybrids pre maturing S. C540،mide maturing S. C647 & Late maturing S. C704 were the sub- factors. Maximum forage yield was obtained for sowing dates 24 July & 2 August to scales 43. 3 & 41. 82 ton/hec respectively and by delaying the plantation due to stem wet weight to scales 52. 8%، corn until 39. 1% leaves wet weight until 52. 0% & corn diameter until 27. 9% the yield of wet forage decreased to 47. 2%. The corn length increased 12. 7% due to delay cropping. Maximum wet forage yield was obtained for pre maturing hybrid 38. 24 ton / h and the minimum was obtained for mid maturing hybrid with 31. 41 ton/ h. The maximum Protein% of forage was obtained for sowing date of 2 th August with 6. 762% and the minimum % for sowing date of 24 th July to scales 4. 037%. The intraction effects of hybrid and sowing date just had significant effect on the corn Length & diameter. For summery sowing of Silo corn in gharakheil in ghaemshahr region، pre maturing hybrid S. C540 by sowing on 24 July is suggestioned.