Abstract

The plant Tamarix chinensis is distributed along the coast of the Yellow River Delta in soils with high salinity. As the dominant local halophyte, it plays a unique role in modifying the local soil microenvironment. We investigated the effects of T. chinensisvegetative cover and the seasons on the soil microbe and microfauna communities in the Yellow River Delta. In April, June and October 2010, soil samples were taken from an estuary of the Yellow River. We measured microbiomass (using the soil chloroform fumigation extraction method), substrate induced respiration (SIR), and phospholipid fatty acids (PLFA). Microbe community structure and soil nematode species richness exhibited distinct seasonal variation. The levels of PLFAs, soil microbial biomass carbon (SMBC), microbial biomass nitrogen (SMBN) and SIR were lower in April than in October in T. chinensis sites. In June, there was a slight increase in the total abundance of PLFA and soil nematode diversity in T. chinensissites. Stepwise regression analysis indicated that plant-feeding nematodes were a dominant factor for changes in soil microbial community composition, and soil moisture, soil organic carbon and fungal-feeding nematode capacity were secondary factors. The distinct seasonal changes in the soil microbe community composition were likely driven by changes in nematode trophic groups, soil moisture and soil organic carbon.

Key words: Microbial biomass, phospholipid fatty acids (PLFA), community diversity,nematode