تنوع گونه‌ای و ترکیب جوامع علف‌های هرز تحت تأثیر گیاه پوششی و رقم آفتابگردان

The experiment was conducted in 2013 to study the influence of cover crop (Fagopyrum esculentum, Medicago scutellata and Vicia villosa) and crop variety (Azargol, Allstar, Farokh) on weed species diversity. The experiment was conducted in factorial design as a randomized complete block with three replications. A total of 15 weed species (11 annuals and 4 perennials) were encountered during the study. The average number of species per 1m2 was 21.6, 25.6 and 23.2 in the Fagopyrum esculentum, Medicago scutellata and Vicia villosa treatments, respectively. Species diversity of the weed community, as determined by the Shannon diversity index, were statistically lower in the F. esculentum than in the M. scutellata and V.villosa treatments. However, no significant difference was identified between the sunflower variety treatments. Result also showed that cover crop and crop variety did not affect species evenness index. Results suggest that including a more allelopathic cover crop such as F. esculentum in weed managment program may reduce weed diversity. Our results also suggest that weed species diversity could be promoted by using less allelopathic cover crop such as M. scutellata and V. villosa.