| A field experiment was conducted at the Experimental farm, state Board for Agricultural Research , Abu – Ghraib during spring and autumn seasons /2006. The objective was to study the effect of plant density on growth of weeds and to determinate the best herbicides affected on yield and yield components of corn. The layout of the experiment was a Split plot in (RCBD) arrangement with three replications. The main plots included the herbicide treatments: control (untreated), 1, 2 Kg/ha Atrazine and 1,2 L/ha Primagram. The Sub plots represent hill spacing (15 cm, 20 cm and 25 cm). The results showed that spraying 2 L/ha of Primagram herbicide significantly increased plant height, leaf area, number of ear, per plant , number of row per area, number of grain per row and grain yield 4.81 ton/ha, 8.54 ton/ha and significantly decreased the dry weight of weeds 52.63 gm, 41.62 gm compared with untreated during spring and autumn seasons respectively. Hill spacing 25 cm superior in dry weight of weeds, leaf area and number of ear perplant compared with others hill spacing (15 cm, 20cm) . There was no significant effect to other characteristics in spring and autumn season. Interaction between spring 2 L/ha of Primgram herbicide and hill spacing 15 cm superior in grain yield 4.83 ton /ha , 8.57 ton /ha and gave less dry weight of weed 27.81 gm , 41.11 gm interaction between untreated treatment and hill spacing 25 cm gave less grain yield was 1.54 ton/ha 2.63 ton/ha in spring and autumn seasons respectively. |