Slope aspect is an important topographic factor, but its effect on the microbial properties of grassland rhizospheric soil (RS) and non-rhizospheric soil (NRS) remain unclear. A field experiment was conducted at the Ansai Research Station on the Loess Plateau in China to test the influence of slope aspects (south-facing, north-facing, and northeast-facing slopes, all with <i>Artemisia sacrorum</i> as the dominant species) on RS and NRS microbial biomass carbon (MBC) and phospholipid fatty acid

more »

... PLFA) contents, and the rhizospheric effect (RE) of various microbial indices. MBC content differed significantly among the slope aspects in RS but not in NRS, and RE for MBC content in the south-facing slope was larger than that in the north-facing slope. RS total, bacterial, and gram-positive bacterial PLFA contents in the south-facing slope were significantly lower than those in the north- and northeast-facing slopes, and RS gram-negative bacterial (G^-) and actinomycete PLFA contents in the south-facing slope were significantly lower than those in the north-facing slope. Differently, NRS total, bacterial, and G^- PLFA contents in the north-facing slope were significantly higher than those in the south- and northeast-facing slopes, and NRS fungal and actinomycete PLFA contents in the north- and south-facing slopes were significantly higher than those in the northeast-facing slope. RE for all PLFA contents except fungal in the northeast-facing slope were higher than those in the south-facing slope. Slope aspect significantly but differentially affected the microbial properties in RS and NRS, and the variable influence was due an evident RE for most microbial properties.