Abstract: By using the methods of experimental ecology and quantitative ecology, this paper studied the Nitraria tangutorum population characteristics under different sand burial depth at southeastern fringe of Tengger Desert, and analyzed the relationships between the population height, coverage, density, and biomass and the depth of sand burial.It was shown that under strong sand burial (at lacustrine basin lowland), the mean values of N.tangutorum population coverage, density, height, and biomass were higher than those under weak sand buried (at alluvial fan), but the coefficient of variation was in adverse. There existed significant correlations between sand burial and the population characteristics except the population density under weak sand burial. The optimum sand burial depth for the development of the population characteristics was higher under strong than under weak sand burial. Whether the sand burial was strong or weak, and whether the optimal sand burial depth was high or low, the development of the population characteristics was all restricted by the optimal sand burial depth. The increase of sand burial depth promoted the development of the population characteristics when the sand burial depth was lower than the optimal depth, but was in adverse when the depth was higher than the optimal. The responses of the population characteristics to sand burial depth were mainly manifested in the height growth and biomass. The development of population coverage and density was not only affected by sand burial, and more importantly, also affected by other factors, especially soil moisture.

Key words: Vetiveria zizanioides, Cyperus alternifolius, Constructed wetlands, Hoggery, Wastewater treatment