Abstract
The importance of the soil type and its properties cannot be denied as one of the major environmental factors affecting the weed community structure in an area, but what is the effect of the other environmental factors as the prevailing climate, crop type, urbanization and crop sustainability? What is the order of importance for their impact? The present study aims to measure these concepts. A sample area (3500 km(2)) was selected in the Northwest Delta, Egypt. 473 species recorded and four VSG or vegetative sociation groups (weed communities) identified using Agglomerative Hierarchical Clustering (AHC). The diversity of the 4 VSG was calculated. PCA used to get a view for the influence of these five variables (environmental factors) on species distribution and variability of weed community structure, summarize the relationships among variables and investigate the proximity among samples and how they relate to variables. The measurement of the degree of seasonal bias of species added more clarification for the impact of crop type. ANOVA followed by Tukey's test showed the significance of 9 soil variables and determined which of the pairs were statistically significant. The results of the study revealed that the prevailing climate was the most impacting factor on species distribution and weed community structure followed by urbanization, crop type, soil type and crop sustainability, respectively.