Biodiversity and community structure of Arthropod in tropical rice fields under organic and conventional ecosystems

The practice of conventional rice cultivation using inorganic fertilizers and synthetic chemical pesticides can affect the stability of ecosystems. This study aimed to compare the diversity and community structure of arthropods in tropical rice field under organic and conventional ecosystems. This research was conducted at Oloboju, located at an altitude of 120 m above sea level. The soil type was inceptisol. The research used observation and exploration methods. The sampling of arthropods in the field used a sweep net, a pitfall trap, a yellow pan trap and by hand. The variables measured were the taxonomic composition and relative morpho-species abundance, family and order composition. Relative morpho-species abundance was assessed based on functional roles, number of species, and the total number of individuals. The results show that the Shannon diversity index value (H') and Margalef richness index (Dmg) were higher in organic rice ecosystems than conventional. On the other hand, the organic rice ecosystem had a Simpson dominance index value (C) and an evenness index (E) lower than the values of C and E in conventional rice ecosystems. The organic ecosystem had a community structure of arthropod of 9 orders, 24 families, and 28 morpho-species, with an abundance of 4,002 individuals, while the conventional ecosystem had a community structure of arthropod of 7 orders, 17 families, and 20 morpho-species with an abundance of 1,789 individuals. The practice of organic rice cultivation would increase the biodiversity index towards ecosystem balance so that it could be used as an alternative to pest control