Evaluation of species, functional and structural diversity of weeds in Golestan province cotton fields

In order to study of flora, functional and structural diversity of weed species, cotton fields of Gloestan province (6 cities) were surveyed during 2012 year. Randomized sampling method as W shape was conducted by using 0.5×0.5-meter quadrate, systematically. In this study, 38 weed species belong to 16 families were recorded which most of them were from Poaceae by 10 species and Amaranthaceae by 4 species. Among different weed families,Poaceae, Cyperaceae and Fabaceae had the most relative abundance in cotton fields, respectively. Based on the results, 76% of recorded weeds were annual and the rest were perennial, also 71% of identified weeds were broad-leaved and the rest were narrow-leaved. Cyperus rotundus and Alhagi camelorum were the most important weeds from narrow-leaved and broad-leaved weeds, respectively. The highest number of species were observed in Ali Abad and Aq Qala (16 species) and the lowest observed in Kord koy (8 species). Among different cities, Ali Abad and Aq Qala (63%), Ali Abad and Galikesh (62%) and Ali Abad and and Bandar Gaz (62%) had the highest similarity index but Kord koy and Aq Qala had the lowest similarity index (8%). The highest Shanon diversity index (2.13) was observed in Galikesh city and the lowest value (1.57) observed in Kord koy city. The highest Simpson diversity index (0.29) was observed in Bandar Gaz and Bandar Torkaman cities and the lowest value (0.15) observed in Galikesh city.