Effect of Nitrogen Sources on Density and Dry Matter of Weeds and Yield of Two Coriander (Coriandrum sativum L.)Landrace

In order to study the effects of nitrogen source on biomass production and density of weed and yield of two corianders landrace، an experiment was conducted by using a factorial arrangement of treatments in a randomized complete block design with three replications، in research farm of Shahrood University of Technology (Iran) in 2010. After standardizing the inorganic nitrogen contents in the soil، 5 levels of N fertilizers (control، 100% vermicompost، 66. 6% vermicompost + 33. 3% urea، 66. 6% urea + 33. 3% vermicompost and 100% urea) were selected and were used for two landrace of coriander (Hamedani and Isfahani). The results of experiment showed that the most important types of weed in coriander farm includes Black Night Shade (Solanum nigrum)، goosefoot (Chenopodium album L.)، Bladder weed (Hibiscus trionum L.) and Wild mustard (Sinapis arvensis L.) respectively. Solanum nigrum had the highest density in all treatments. Level of fertilizer had significant effect on biomass production and density of weeds، seed yield and biological yield of coriander (P≤0. 01). Effect of landrace was not significant in all traits and interaction effect of fertilizer and landrace was significant only in seed yield and biological yield of coriander. The maximum and minimum biomass production and weed density was observed in 100% urea and control treatments respectively، also the highest amount of seed yield and biological yield are associated in (66. 6% vermicompost and 33. 3% urea)، the lowest level of mentioned traits are associated in control (no fertilizer) treatment. According to the results، combination of organic and chemical fertilizers can reduce density and biomass production of weed، and increases the yield of coriander.