Abstract

Hassan Sher and Mohammed N. Al-Yemeny

A radical change has been observed in various agronomic practices including increase in crop productivity which lead to changes in the composition, diversity and abundance of weed flora in arable as well as in non-arable lands. In this context, a survey was conducted both in agricultural and non-agricultural areas in different parts of Al-Kharj (Saudi Arabia). The aim of the study was to prepare an ecotaxonomical inventory of weed flora useful for ecological management in the survey area. The study documented 52 weed species belonging to 27 families including 25 dicots and two monocots families (Lilaceae and Poaceae). Poaceae (8 spp.) followed by Asteraceae (5 spp) and Solonaceae (4 spp.) are the largest families while the remaining are represented either by three or less than three species. They comprises of thirty five herbs, eight grasses, seven shrubs and each climber and parasite have one species in the area. The 52 weed species includes annual herb (28), annual grasses (5), perennial shrub (7) and perennial herb (6). Out of 52 weed species, Chaemophytes (5), therophytes (30), hemicryptophytes (12), geophytes (3), and one nanophaneorophytes. The results showed that the relative availability of common weed species has generally decreased during the last decena. According to their availability, they were classified dominant (5 spp.), rare (6 spp.), respectively occasionally available (18 spp.), and frequently available (23 spp.). Most of these weeds causes moderate to severe infestation to various agricultural crops. The study concluded that weed communities has significance value in agro-ecosystem function and, therefore, its ecological management for conservation of biodiversity is utmost important. This finding suggests that disturbed habitats may be important areas to search for novel compounds in drug discovery.