عنوان مقاله [English]
In order to simulate the effects of soil nitrogen and straw mulch on weed infestation and yield of Dracocephalum moldavica; an experiment was conducted in 2014. The first factor was of nitrogen in three levels including non-fertilization, and 50 and 100 kg ha-1 into the soil to create different levels of nitrogen in the soil and the second factor was mulch amount in four levels including: without mulch as a check, mulching with 1, 1.5 and 2 kg m-2. A plot with hand weeding was also considered as a check. Biomass and density of broad-leaved and total weeds at 70 days after planting, significantly affected by the amount of mulch and interactions of mulch× nitrogen. Both density and biomass of grass weed only affect with mulch amount. At the end of the season sampling, biomass of broadleaf and grass weeds was affected by both factors and their interaction as well. While, for total weeds only mulching effects was significant. At the end of the season, the highest broadleaf and grass weeds biomass was observed when 100 kg N ha-1 used without mulching. Overall, plots without mulch and the use of 2 kg m-1 of mulch had the highest and lowest weed biomass, respectively. Compared to, the biological yield of D. moldavica was decreased from 5495 kg ha-1 in to 8525495 kg ha-1 in weedy check. Except for weed free treatment, the highest seed and biological yield was obtained in plot with 100 kg N ha-1 and 1 kg m-2 mulch.