Soil samples were collected to a depth of 20 cm using a 3.0 m × 3.0 m grid in 900 m 2(30.0 m ×30.0 m) plots for analysis of spatial patterns of soil in undisturbed area of China fir(Cunninghamia lanceolata) and Masson pine(Pinus massoniana) mixed forest in the Three Gorger Reservoir Areas.The investigation data showed that the average of soil DNA content was 922.71 μg·g-1 water-free soil,the maximal value was 6 761.30 μg·g-1 water-free soil,and the less value 58.52 μg·g-1 water-free soil.The geostatistical analysis indicated that the spatial distribution characteristic was not obviously reflected by the liner graphs while samples were randomly distribution and independent each other.The separation distance among samples was related to precision of soil DNA content,the effects of non-structure factors(environment factors,disturbed factors) on spatial correlation structure would disappeared due to the separation distance in excess of 18.84 m,and the spatial correlation of soil DNA faded down in plots.Spatial variability in soil DNA in the region was mostly contributed by the influencing factors including soil nitrogen,soil organic matter and content of soil water.
