Abstract:

The distribution characteristics and controlling factors of soil selenium in the surface layer of cultiva-ted land were analyzed based on the investigation of cultivated land quality in Zhenyuan County. The results showed that the average soil Se content of cultivated land is (0.64±0.56) mg /kg, Se content of the Se-rich cultivated land is (0.72±0.42) mg /kg. The area of Se-rich cultivated land accounted for 82.71% of the total cultivated land area in Zhenyuan County. The content of soil selenium in cultivated land is affected by pH value, elevation, landform, parent rock, soil type and land use type. Also, the results showed that there are relatively high selenium contents in the acid cultivated land, the cultivated land below 800 m above sea level, the cultivated land in furrow and valley, the cultivated land in carbonaceous strata, the coarse-grained soil and red soil, the soil in tea garden and paddy field. It is considered that the parent rock is the most important source of soil selenium, which controls the content of selenium in soil, especially the carbonaceous siliceous rock series. In addition, soil organic matter and pH can change the physical and chemical properties of soil and affect the migration and accumulation of Se, and then affect the content of Se in soil.

Key words: controlling factor, distribution characteristic, selenium content, cultivated land, Zhengyuan County of Guizhou Province