Objective Due to the action of crustal uplift and river undercutting, the Xinsheng basalt tableland located in Zhejiang Province had a special landform composed of the main body of tableland (center of tableland and edge area of tableland) and tableland front (slope area of tableland front, platform area of tableland front and near valley area of tableland front). Understanding the evolution law of soil properties and soil types in different topographic positions of the landform and the relationship between topographic positions and soil genesis can provide basis for soil survey and mapping.

Method The soil profiles from 32 points were investigated in different topographic positions of basalt concentrated distribution areas in the Xinsheng basin. The morphological characteristics, chemical properties, mineral types and nutrient elements of the soils were systematically characterized, and the soil types of different topographic positions were identified according to the diagnostic criteria of Keys to Chinese Soil Taxonomy.

Result The results showed that there were significant differences in soil genetic characters among different topographic positions. Soil thickness was the deepest in edge area of the tableland and the thinnest in slope area of the tableland front. The main hue of the soils on main body of the tableland was mainly between 5YR and 2.5YR with the red rate of 6.00 to 15.00, while the hue of the soils in the front of the tableland was mainly between 7.5YR and 10YR with the red rate of 0.00 to 3.33. The main texture of the soil on main body of the tableland was clay, and that of the soils on the front edge of the tableland was mainly clayey loam with high amount of gravel. The content and degree of free iron oxides in the main soils on main body of the tableland were significantly higher than those on the front of the tableland, and the soil iron oxide of the former was composed of goethite and hematite, while for the latter only goethite was identified. The soil development indexes such as weathering leaching coefficient, clay silicon aluminum ratio, mineral type and cation exchange capacity showed that the weathering and development intensity of the soils on main body of the tableland was significantly higher than those of the front area of the tableland. The soils on the main body of the tableland (including the tableland center and the tableland edge area) was mainly Ferrosols, the platform area and near valley area of the tableland front were mainly distributed with Cambosols, and the slope area of the tableland front was composed of Cambosols and Primosols.

Conclusion The results indicated the effects of the topographic positions of basalt tableland on soil formation and development were mainly due to the change in soil formation relative time caused by different erosion intensity and the change of soil water status caused by topography. The surface ground of main body of the tableland is stable, which is conducive to the deep development of the soils. The front edge of the tableland is affected by soil erosion and with poor drainage conditions, which affects the leaching of base materials and soil development.