Abstract: The study with gnotobiotic microcosm showed within the range of test soil moisture con-tents, the feeding activity of Caenorhabditis elegans on Bacillus subtilis promoted the latter’s prolif-eration, and enhanced soil respiration significantly. The increment of B. subtilis number varied with soil moisture content, and decreased in the order of 23%>17%>28%. The interaction of C. elegans and B. subtilis increased the contents of soil mineral N and NH₄⁺-N significantly, indicating that soil nitrogen mineralization was markedly promoted. A higher nitrogen mineralization rate was obser-ved under 23% soil moisture content.

Key words: Arbuscular mycorrhizal fungi, Tagetes erecta, Growth indexes, Diesel degradation