Abstract: By the methods of geostatistics, this paper studied the spatial structure and distribution pattern of surface soil (0～5 and 5～10 cm) moisture content inthe depression area of karst region in northwest Guangxi under moist and arid conditions in the forepart of dry season. The results showed that in test area, surface soil moisture content had obvious spatial heterogeneity and anisotropy, presenting a significantly different plaque distribution pattern. Under moist condition, surface soil moisture content had a medium or stronger spatial relativity, with a range of about 33.15 and 15.75 m, respectively, and an obvious trend effect in 0～5cm soil layer. Under arid condition, the spatial relativity was strong, and the spatial scale of resembling plaque had somewhat decrease, with the smallest range being 8.22 m. The moisture content under arid condition had a higher spatial variability, and thus, the sampling strategy should be based on the mean soil moisture content. The significant difference in the spatial variability and distribution pattern of surface soil moisture in test area was mainly due to the effects of physiognomy, soil mean moisture （precipitation）, and topography.

Key words: Microcystis aeruginosa, Phosphate, Aqueous ecosystem, Temperature, Translocation, Isotope tracer