Abstract: We investigated carbon (C), nitrogen (N), phosphorus (P) and potassium (K) ecological stoichiometric characteristics in plant and soil of Alhagi sparsifolia population (LTC), Karelinia caspiapopulation (HHC) and A. sparsifolia-K. caspia community (GSQL) in the south rim of the Taklimakan Desert. The results showed that the concentrations of available N (AN), available K (AK), N∶P, and N∶K in GSQL soil were significantly higher than those in HHC soil. The concentrations of total N in GSQL leaves were significantly higher than those in HHC leaves, while the concentrations of total P in GSQL leaves were significantly higher than those in LTC leaves. Results of the correlation analysis showed that soil AK concentrations were positively correlated with N∶P and AN across different habitats, but negatively correlated with SOC concentrations. Across all the habitats, foliar K concentrations were positively correlated with SOC, total N and total P concentrations, respectively; foliar N concentrations were positively correlated with SOC and total P concentrations, while N∶P was negatively correlated with SOC and total P concentrations. The SOC concentrations were positively correlated with foliar P and K concentrations, but negatively correlated with N∶K. Soil AN concentrations were positively correlated with foliar N∶K, but negatively correlated with these four element concentrations in leaves. Soil AK concentrations were negatively correlated with these four element concentrations in leaves and positively correlated with N∶K in leaves. Soil N∶P and N∶K were positively correlated with the foilar total C, total P, total K concentrations, respectively. In brief, A. sparsifolia-K. caspiacommunity can improve nutrient state of soil and plant compared with single-species population, suggesting the significance of leguminous species A. sparsifolia in community succession. Our results could provide scientific basis for the restoration of desert ecosystem in the south rim of the Taklimakan Desert.

Key words: weighting lysimeter, grassland evapotranspiration, diurnal variation., upper reach of the Heihe River