Two typical slopes of 35-year-old Larix principis-rupprechtii plantation (southeast slope A and south slope B) were chosen to be studied in order to elucidate the spatial characteristics of soil moisture under the influence of rainfall and vegetation factors such as canopy leaf area index and litter layer thickness in forest land. Following the principles and methodology of spatial pattern analysis in geostatistics

and took the characteristics of the selected slopes into consideration

the linear sampling method were chosen to measure the moisture of surface (0—20 cm) and subsurface (20—40 cm) soil

canopy leaf area index

litter layer thickness

slope degree and distance from the nearest tree trunk. The spatial variation characteristics of soil moisture before and after raining were analyzed combining with classical statistics and geostatistics methods

the relationship between soil moisture and the main environmental factors before and after raining were analyzed using the Pearson correlation analysis

the spatial distribution of soil moisture before and after raining on the slopes was obtained by Kriging interpolation. Result indicated that there was significant spatial autocorrelation of soil moisture of surface and subsurface layer on both selected slopes. In addition

the soil moisture presented an obvious patchy distribution pattern. Before raining

structural ratio of surface soil water content were 0.20 and 0.16 respectively on slope A and B

indicated that soil moisture of surface layer had a strong level of spatial autocorrelation selected slopes. Meanwhile

the structural ratio of subsurface soil water content was 0.50 on both slope

soil moisture of subsurface layer indicated medium level of spatial autocorrelation on both chosen slopes. The range of the autocorrelation functions of surface soil moisture on slope A and B was from 27.6 m to 23.7 m

and the range of subsurface soil moisture was from 54.9 m to 186.0 m respectively

manifested that spatial autocorrelation of the soil moisture existed in a large range. After raining

the structural ratio of surface soil water content were 0.13 and 0.11 on slope A and B

the ratio of subsurface were 0.28 and 0.20 respectively

the range of the autocorrelation functions of surface soil moisture was from 17.7 m to 17.3 m

and the range of subsurface was from 31.4 m to 42.6 m respectively. Those results indicated a shrinking trend of the range of spatial autocorrelation after rainfall. Pearson correlation analysis revealed that before rainfall

the distance from the nearest tree trunk and litter layer thickness made the main impact factors of the spatial variation of soil moisture on slope A. However

canopy leaf area index and litter layer thickness became more significant variables after raining. So

this precipitation process (11 mm of rainfall amounts) increased the spatial heterogeneity and autocorrelation of soil moisture

in addition

the interception and redistribution of rainfall caused by the tree canopy and litter layers was the main reason of the increase of the soil moisture spatial heterogeneity in the study area.