%0 Conference Proceedings %T Effect of Plant Diversity and Nutrient Resource on WeedComposition and Density in Different Cropping Systems %A , %A Koocheki, Alireza %A Rezvani Moghaddam, Parviz %A Nassiri Mahallati, Mehdi %A Alimoradi, Leila %A Siahmarguee, Asieh %J Competition for Resources in a Changing World %D 2008