Weeds flora demographic analysis of date palm orchards in El-Bahariya, El-Frafra and Siwa oases.
Oases are a specific ecosystems which date palm Phoenix dactylifera are the mainly crop growing for its fruits and others tree parts. Palm orchards are infested by many pests, including weeds species and exposed within time to the challenging invasive weeds to control. The heavy incidence of weeds negatively affects palm productivity, especially in small plantation and divergent distances, while the established orchards, palm trees shading cause deprives from the process of weeds photosynthesis to be lower competitive. The survey was conducted in El-Bahariya and El-Frafra than Siwa oases of which 375 plots were taken. Vegetative analysis in oases altogether demonstrate 91 weed specimens were encountered of which 18 perennial, 42 were broad leaved, and 30 narrow leaved as well as one parasitic weed species belonging to 22 families, whereas Poaceae is the most plentiful family displayed by 38.5% from all families, occurred in date palm orchards during the study. The geographical differentiation affected coefficient of similarity whereas, it in oases recorded the highest between El-Bahariya and El-Frafra than Siwa and El-Bahariya, while El-Frafra Oasis was the most diverse and richness than the others which have the middle soil properties, fertility, and structure. The correlation analysis of weed flora between both El-Bahariya and El-Frafra was higher and more than El-Bahariya and Siwa oases. Under the unique closed agroenvironment of oases, weeds population dynamics are a stable approximately. Regardless of the diversity of annual weed species, perennials species represent the highest dominant number and the pattern of grown weeds was more dominant than wild desert and some invasive weed species. The control action should be taken of perennial weeds and proactive as well as long term prevention for invasive species.