<![CDATA[ABSTRACTSoil fungis are one of the soil microbes that can be beneficial or detrimental to plants, so they play an important rolein agriculture. This study aims to determine the abundance and characterization of soil fungi in the rhizosphere ofmustard greens. Isolation and identification of soil fungus was carried out in the Pest and Disease Laboratory of theFaculty of Agriculture, University of Borneo Tarakan. The fungus was characterized macroscopically andmicroscopically, and the pathogenicity test, phosphate dissolution activity test, proteolytic activity test and chitinhydrolysis test were carried out. The results of the study obtained 34 fungus colonies. Based on the phenotypiccharacteristics there were 9 fungi isolates with different characteristics, 4 isolates from 9 isolates were non-pathogenic.In non-pathogenic fungi isolates, 2 genera were obtained, namely genus Phialophora sp. and Paecilomyces sp. Thereare non-pathogenic fungus isolates that have proteolytic activity and chitin hydrolysis so that it has the potential as abiological fertilizer and biological agentKeywords: Soil fungis, rhizosphere, characterization ABSTRAK Cendawan tanah merupakan salah satu mikrobia tanah yang dapat bersifat menguntungkan atau merugikan bagitanaman, sehingga berperan penting dalam bidang pertanian. Penelitian ini bertujuan untuk mengetahui kelimpahandan karakterisasi cendawan tanah di daerah rizosfer sawi. Isolasi dan identifikasi cendawan tanah dilakukan diLaboratorum Hama dan Penyakit Fakultas Pertanian Universitas Borneo Tarakan. Cendawan tanah dikarakterisasisecara makroskopis dan mikroskopis, dan dilakukan uji patogenesitas, uji aktivitas melarutkan fosfat, uji aktivitasproteolitik dan uji hidrolisis kitin. Hasil penelitian diperoleh 34 koloni cendawan. Berdasarkan karakteristik fenotipterdapat 9 isolat cendawan dengan karakteristik yang berbeda, 4 isolat dari 9 isolat bersifat non patogen. Pada isolatcendawan yang non patogenik, diperoleh 2 genus yaitu genus Phialophora sp. dan Paecilomyces sp. Isolat cendawannon patogenik yang diperoleh ada yang memiliki aktivitas proteolitik dan hidrolisis kitin sehingga berpotensi sebagaipupuk hayati dan agens hayati. Kata kunci: Cendawan tanah, rizosfer, karakterisasi]]>
