Floristic Composition and Diversity of Weeds in Organic Rice Fields in Langkong, M’lang, Cotabato

This study investigated the floristic composition and diversity of weeds in organic rice fields in Langkong, Mlang, Cotabato covering an area of 2.5 hectares within which 100 quadrats were randomly assigned. Identification of weeds showed thirteen species belonging to six families eight of which are annuals and five perennials comprising five broadleaf, three grass, and five sedge types. All weed species had <50% uniformity which may imply less competitiveness against rice or effective control by weed management practices. Fimbristylis littoralis and Cyperus difformis have the highest frequencies and the highest field uniformities and highest mean field densities indicating that these weeds are the most difficult to control. The weed density of fields in which the species occurred increased compared to densities from all fields for all weed species that may mean that site-specific or management-specific factors contribute to the survival of those species. Relative abundance values showed that Fimbristylis littoralis and Cyperus difformis are the two most dominant weed species. Weed species diversity is medium and equivalent to 5 equally abundant species.