عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to evaluate the effects of planting dates and weed management time at different growth stages of dill on species diversity trends for weeds based on diversity indices, an experiment was performed as factorial layout based on a randomized complete block design with three replications at the Agricultural Research Station, Shirvan College during growing season of 2011-2012. Treatments were four planting dates (22nd December, 21st January, 20th February and 20th March) and three weed control stages including the first true leaf, start of branching and beginning of flowering stages of dill. Weed samplings were done at three growth stages of dill before hand weeding. The results showed that the weeds affected by planting dates and control stages. So, broad leaves (13 weed species) with annual cycle (12 weed species) and C3 (16 weed species) were dominant. The highest relative frequencies for the first, second and third sampling stages were calculated in monk’s rhubarb (16.53%), corbcille (23.53%) and lamb’s-quarters (28.75%), respectively. All weed species had sustainable coefficient less than 25% for the first and the second stages. At the first sampling stage, dominant coefficient was 0.444-0.952% and these ranges were 0.626-2.789 and 0.958-1.698% for the first and the second sampling stages, respectively.