THE DIFFERENTIATION CHARACTERISTICS OF SOIL SEL-ENIUM IN WARM-TEMPERATE GEOGRAPHIC LANDS-CAPE
暖温带地理景观中土壤硒的分异特征

The selenium differentiation in mountain meadow soil, mountain brown soil, mountain leached drab soil and cultivated fluviogenic soil in warm-temperated geographic landscape has been studied according to vertical natural zonality. The results show as follows: 1. Besides affected by the biological enrichment, the selenium distribution in soil profile is greatly affected by the eluviation and granulitization. 2. The selenium content in clay is the highest, which gradually decreases with series of clay> fine powder > middle powder > sand. In the soil-forming process, the soil mechanical composition, the vertical movement and natural gradation of secondary and epigenetic mi-nerals play important roles in the soil selenium differentiation. 3. The contribution rate of easy leaching selenium associated with organic and calcium is more than 50 percent in the studied surface soils. This shows that eluviation is the dominated exogenic force in the forming of low selenium belt of China.