Floristic study of weeds of saffron (Crocus sativus L.) fields in Cheshmesaran district in Azadshar

A research was conducted to study floristic of weeds of saffron (Crocus sativus L.) fields located in Cheshmesaran district in Azadshar to report distribution and species diversity of weeds population. For this purpose, saffron fields under cultivation over 3 hectares was identified in three regions, including Narab, Vamenan and Tillabad village. Identification and sampling of weeds was done in vegetative growth stage of saffron (daughter corms) in 2017. 45 quadrates were used for each farm and then number and type of weed species each quadrat was counted separately. Weeds species based on Persian name, scientific name, genus, family, leaf shape, photosynthetic pathway, growth habit and life cycle were classified. Results of species composition of weeds in saffron fields of triple regions showed that Narab region with 54 species had the largest number of species. Veronica persica Poir weed and Stellaria midia in Narab and Veronica persica Poir in Vamenan were the dominant weed in these regions which had the highest relative density and frequency. In return, Hordeum murinum in the Tillabad region had the greatest density and frequency. This could be due to the differences in geographical coordinates, climatic conditions of sampling locations, competitive ability of weeds and management methods to control them in saffron fields. The results of species diversity of weeds showed that Narab and Tilabad included highest and lowest dominance index, which were about 0.13 and 0.08, respectively. In return, the highest Menhinick richness, Margalev and uniformiy of weeds were recorded in the Narab region about 0.67, 2.55 and 0.97, respectively. Narab and Vamenan regions also had maximum numerical value of Simpson (0.92) and Shannon- Wiener indices (2.64). Overall, the results showed that saffron fields of both regions of Narab and Vamenan were most similar in term of weed species number and population indices.