اثر زمان نسبی سبز شدن و تراکم علف هرز سلمه تره (Chenopodium album L.) بر عملکرد دانه و بیولوژیک ذرت دانهای (Zea mays L.)

Abstract

Abstract To study the effect of competitive potential of corn (Zea mays), in competition with common lambsquarters (Chenopodium album) an experiment was conducted in 2006, at the farm of Agricultural Faculty of Ferdowsi University. In this experiment the effect of relative emergence time of common lambsquarters on single Cross 704 corn yield was studied in different densitis of the weed. The experimental design was split plot based on randomized completed block design with three replications. The emergence time at 3 levels (emergence of the weed 14 days earlier, 7 days earlier and simultaneously with corn) was considered as main plots and density of weed at 6 levels (0, 4, 8, 12, 16 and 20 plants m-2) as sub plots. The results showed a decrease in grain and biological yield of corn, as the emergence time of corn delayed in comparison with the emergence time of weed. The maximum yield reduction of 100 and 99% was observed respectively, in the earliest emergence time of common lambsquarters compared to corn and in the highest density of weed (20 plants m-2) where the corn plants were fully shaded by the weed canopy and no ear was produced. The yield loss of corn was higher when the earlier emergence time of weed was occurred in higher weed densities. based on the results of this research it can be concluded that the decrease of competitive potential of corn with increasing the relative emergence time of common lambsquarters was led to significant yield loss of corn crop. While the increase in weed density resulted in corn yield reduction, there was no difference in yield loss in high weed densities. Keywords: Biomass, Competition, Weed interference model, Yield loss