Abstract: Using statistics and RDA analysis, the spatial variability of soil nutrients in the hilly area of the Dabie Mountains was studied, and the distribution characteristics of its topographical factors were discussed. The results showed that moderate level of spatial variability occurred in 6 nutrients contents in the research region, and the variability of available phosphorus, available potassium and available nitrogen were stronger than total nitrogen, total phosphorus and organic matter. The nugget/still ratios were 59.05% for available and which could be modeled with the Exponential model. The nugget/still ratios were 20.25% ,44.81% for total phosphorus, available potassium respectively, which could be modeled with the spherical model. While nugget/still ratios were 43.10%,20.41% and 48.57% for organic matter, total nitrogen and available nitrogen respectively, which could be modeled with the Gaussian model. Total nitrogen and total phosphorus showed strong spatial autocorrelation, while other nutrients showed moderate spatial autocorrelation. Quantitative analysis showed that 11 factors could explain 54.7% of spatial variability in this nutrient, 44.6% of which was explained by level I terrain factors, 10.1% by level II terrain factors. Among of all topography factors, elevation, slope aspect and slope position could explain15.2%,14.1% and 7.1% of soil nutrients variability, respectively. The factors were significantly correlated with soil available potassium at P<0.05 level, which were the main factors affecting the spatial distribution of soil nutrients in the in hilly area.

Key words: soil nutrient, spatial variability, RDA, topography factors