Abstract: The species composition and soil characteristics of black wolfberry communities in four different types of desert rangeland (loose sand dunes, salt flats, gravels, vegetated or semi-vegetated dunes) in the lower reaches of the Shiyang river were studied. Key content of this paper includes: 1) Among the plant communities investigated, there were 31 species (12 shrub plants, 8 perennial herbs and 11 annual herbs) belonging to 9 families and 28 genera. Hence the community structure at each studied site typically comprised a few families represented by a single taxon from one or more genera. Lycium ruthenicum had a dominance role in each of the 4 communities with ‘importance values’ of 58.9%, 17.6%, 18.2% and 38.1%, respectively, for the above 4 site categories. Only at the gravel flats site was another species more important (Setaria viridis, 28.9%). 2) A range of soil chemical properties are tabulated for 0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm soil depths. Soil organic C for the 0-10 cm soil depth was 0.30%, 1.08%, 0.29%, and 0.37% (mean s.e.±0.05%), respectively, for loose dune, salt flat, gravel and vegetated dune sites. The measured soil properties generally did not vary significantly with soil depth, but along with SOC, soil total P and available K were markedly higher in saline flats than at the other site categories. 3) Site rankings for soil microbial biomass were saline soil (-300 mg·kg^-1)>loose sand>vegetated dunes>gravel (-125 mg·kg^-1). Soil enzyme activities are reported for the 4 soil depths for catalase, sucrose, urease, phosphatase and invertase, and were highest in the saline soil in each case. 4) There was a significant positive correlation between soil organic matter and microbial biomass carbon, microbial biomass nitrogen, phosphatase and sucrase (P<0.01), and a significant positive correlation with urease and catalase (P<0.05). Phosphorus content was significantly positively correlated with urease, phosphatase and invertase (P<0.01), and positively correlated with microbial biomass carbon (P<0.05). Soil available potassium content was significantly positively correlated with microbial biomass nitrogen and phosphatase (P<0.01).

Key words: the lower reaches of Shiyang River, desert rangeland, Lycium ruthenicum community, vegetation structural features, soil characteristics