The Effect of Nitrogen Application and 2-4-D on Weed Density and Weed Architecture in Winter Wheat

To study the effect of nitrogen application and 2-4-D on weed density and weed architecture in winter wheat an experiment was conducted at agricultural research site, university of Mohaghegh Ardabili, Ardabil in 2009. Treatments were two nitrogen levels (no fertilizer and 150 kgNha-1 application) with or without 2-4-D (1.5 kg ai ha-1). Results showed that nitrogen application had no significant effect on weed density. Nitrogen application has increased weed dry weight to two-fold. Nitrogen application increased weeds dry weight on top layers of wheat canopy. 2-4-D application decreased weed density and weed dry weight. 2.4. D decreased density of annual spring weed over 90%. Wheat yield increased to 44% when herbicide applied compare to no herbicide application. Wheat yield was not significantly affected by N application.