Abstract: Taking a long-term experiment in the black soil area of Northeast China as the platform, this paper studied the abundance of soil bacteria, crenarchaea, and ammoniaoxidizng archaea in grassland, cropland (soybean, corn, and wheat), and bare land by targeting the 16S rRNA gene and amoA gene with real-time PCR approaches, aimed to evaluate the functions of main microbial groups in soil ecosystem under different land use types. The results showed that the abundance of soil bacteria, crenarchaea, and ammonia-oxidizing archaea was significantly higher in grassland than in cropland and bare land, but had no significant difference in different crop lands. As compared with that in bare land, soybean land, corn land, and wheat land, the abundance of bacteria, crenarchaea, and ammonia-oxidizing archaea in grassland was increased by 62.7%, 29.0%, 41.1% and 18.8%, 34.4%, 30.7%, 37.6% and 33.7%, and 28.6%, 42.6%, 44.4% and 53.6%, respectively. The abundance of soil bacteria had significant positive correlations with soil pH (r=0.935, P<0.01) and organic carbon content (r=0.887, P<0.05), that of soil crenarchaea was significantly positively correlated with soil pH (r=0.845,P<0.05), whereas the abundance of soil ammonia-oxidizing archaea had no significant correlations with soil pH and organic carbon content.

Key words: forest litterfall, geostatistics, climatic factor, model, spatial pattern, remote sensing.