Identification and Survey of Weeds Community Indices in Alfalfa Fields of Shabestar

In order to weed flora survey in the fields of alfalfa 56 fields of alfalfa for two years (201 2011) were investigated at the Shabestar County in East Azerbaijan province.. A total of 130 weed species from 28 families were observed within these fields. 68% and 14% of weed species were dicotyledon and monocotyledon, respectively. Dominant weeds in alfalfa fields of Shabestar county were mouse foxtail (Alopecurus myosuroides Hudson), field bindweed (Convolvulus arvensis L.), buckhorn plantain (Plantago lanceolata L.), and downy brome (Bromus tectorum L.) between 130 species with dominance index of 96.38, 94.69, and 89.95, respectively.. Between investigated districts, Garaaghaj and Dizajkhalil with 74 and 17 weed species had highest and lowest richness, respectively. Mean density of weeds in these districts were 12.58 and 30.43 plant m-2. Claster analysis of data with Shanon-Wiener index classified different districts of Shabestar County in three groups. Garaaghaj and Gholmansaray with highest Shanon-Wiener index were located in group one, Aliakbarlo, Till, and Ivand were located in group two, and Dizajkhalil and Ammand with lowest Shanon-Wiener index were located in group three. These results showed that some weeds could be dominant in areas by low richness but high density because of some specific weed management methods.. Therefore, farmers should be changeweed management methods in this regions.