The Study of Dispersal of English Title Dominant Grass Weeds of Irrigated Wheat Fields of Iran and Determine the Effective Environmental Factors

This experiment was conducted to study the effects of some environmental factors on dispersal and density of five dominant grass weeds including of Avena ludoviciana، Avena fatua، Phalaris minor، Lolium rigidum، Secale cereal in irrigated wheat fields of Iran. Altitude، annual mean of soil temperature، rainfall and evaporation were got from topography and climatic maps، was used as environmental factors in this experiment. Also، abundance percentage of mentioned weeds was determined in different kinds of climate (based on cilianinov method) and 10 types of soil in Iran. According to the results، among studied environmental factors، altitude and annual mean of soil temperature on density of Phalaris minor، altitude and annual mean of soil temperature and rainfall on density of Lolium rigidum and Avena fatua، annual mean of soil temperature، rainfall and evaporation on density of Avena ludoviciana and annual mean of soil temperature on density of Secale cereal had the highest effect. Study of these weeds dispersal in different climates showed that Avena fatua and Avena ludoviciana had the highest and lowest dispersal in different climates، respectively. Also، Avena ludoviciana and Lolium rigidum had the highest and lowest consistency in different soil types، respectively.