The relationship between soil salinity in the top soil of nebkhas and annual litter-fall production of tamarisk shrub was analyzed to clarify the distribution of soil salinity patterns in and outside Tamarix nebkhas and their effects on oasis ecosystem.Results indicated that soil salinity in nebkhas surface soil(0-30cm)was lower than in internebkhas.Annual litter production was found to be an important factor reducing soil salinity in surface soil beneath the canopy according to correlation analysis.In contrast

soil salinity enrichment was observed in deeper soil layer(30-120cm)in the Tamarixnebkhas compared to internebkhas

which indicated the formation of salinity islands in nebkhas.K+

Na+

Cl-and HCO3 were the four important ions enriched in resource islands.The other three ions(SO42-

Ca2+and Mg2+)were distributed evenly or randomly in deeper soil.These results suggested that the Tamarix nebkhas gathered soil salinity from internebkha spaces.The fate of Tamarixnebkhas will affect the stability of oasis ecosystem in the arid zone.