Evaluation of Sorghum (Sorghum bicolor (L.) Moench) Ability to Control Weeds in Corn (Zea mays L.)

In order to evaluate the weed control ability of sorghum in corn, a field study was carried out in 2006 at the Agricultural Research Farm of Razi University, Kermanshah, Iran. Sorghum plant materials were applied in three ways : (1) incorporated into the soil (at 2,000, 4,000 and 6,000 kg ha -1 ) mulched on the soil surface (at 2,000 and 4,000 kg ha -1 ) or sprayed as sorgaab (water extract of mature sorghum plants) one, two, three or four times during the growing season. Two controls(full-season weedy and weed-free condition) were also included. Full season weed-free condition increased height, the number of ears per plant, the number of seeds per ear, 100 seed weight and yield of corn by 67.9, 35.8, 66.1, 23.3 and 47.8%, respectively, as compared with weedy condition for all of the growing season. Among the sorghum treatments, the highest corn plant traits and the lowest weed dry weight and density were occurred when sorghum herbage was incorporated into the soil at 6,000 kg ha -1 or used as a mulch at 4,000 kg -1 . However, corn yield and weed dry weight and density were not significantly influenced by one sorgaab spray, when compared with full season weedy condition. In general, this study revealed that sorghum plant materials applied in different forms can suppress weeds in corn field.