KERAGAMAN DAN KEMELIMPAHAN ARTHROPODA TANAH PADA LAHAN MONOKULTUR Zea mays L KEBUN PENDIDIKAN, PENELITIAN DAN PENGEMBANGAN PERTANIAN UGM (KP4 UGM)

Soil arthropods have aimportant role in soil ecosystem by decomposition of organic materials to keep nutrient cycling in agriculture ecosystem. Diversity and abundance soil arthropod population can be disturbed when the agroecosystem was applied with insecticide. Seasonal differen can influence insecticide degradation. Zea maysmonoculture at the KP4 UGM consist of two kinds plant area which was applied by pyrethroid insecticide deltamethrin (Blok 1D9) and without insecticide application (Blok TP1). The aim of this research is to calculate the diversity and abundance of soil arthropod populations in both block and seasonal influence to soil arthropod population. This research was conducted on July until September (dry season) and October until December 2013 (rainy season). In this research, soil sample was extracted by Tullgreen funnel within 3 days, soil arthropods were identified based on family number, absolute density and important value. Diversity was calculated based on Shannon-Wiener index. Residue of deltamethrin was determined by using fluid chromatography mass spectroscopy. Soil arthropod family was identified then divided into the feeding groups of microphytic feeders, saprophytic feeders, phytophagus feeders and carnivore. The highest absolute density observed at Block 1D9 Block during dry season was Laelapidae, Block TP1 being Hypogasturidae. In rainy season, the highest absolute densities of both blocks was Oribatidae. Diversity indexs in dry season at Block 1D9 and TP1 were 3,1 and 2,8 whereas in rainy season being 3,1 and TP1 were 2,9. Based on the results deltamethrin affectes the abundance and diversity of soil arthropods