Abstract: Systematic investigation and analysis of arthropod in spring Z. mays in the suburbs of Chongqing was carried out during 1998-1999.The component structure and biodiversity of the arthropod community were studied according to the species,guilds and nutrient classes.The results indicated that there are 320 species of arthropod in spring Z. mays in the suburbs of Chongqing City.Among this,43.8% is pests,48.4% is natural enemies and 7.8% is other neutral insects.All of the arthropod was divided into 4 nutrient classes,7 guilds,and 22 groups,which include plant-eating groups,natural enemy groups and others.These groups directly or indirectly depend on corns and make up an integrated food chain.Every natural class has its dominant species and key species.But these species change with the growth of corns.In this paper,the function of the dominant species,dominant groups and guilds in the integrated pest management was analyzed.The relationship between abundance, bio-diversity and key species was also analyzed.It is indicated that key species play an important role in pest control.

Key words: dissolved organic carbon, mineralization, soil moisture, paddy, upland.