DISTRIBUTION CHARACTERISTICS AND MAIN INFLUENCING FACTORS OF SOIL MOLYBDENUM IN OROQEN QI, INNER MONGOLIA

Molybdenum(Mo), an essential trace element for animals and plants, comes directly or indirectly from soil. Based on the soil sample data obtained from the 1:250 000 land quality geochemical survey in the main cultivated areas of Oroqen Qi in Inner Mongolia, the paper evaluates the nutrient grades of Mo content in the surface soil of the study area. The results show the soil Mo contents generally reach the rich-grade and above. Besides, the influences of geochemical indexes, soil types and parent materials on soil Mo content are also analyzed. It is considered that the Mo content decreases as pH increases when pH is 5-7, and decreases as organic content increases when Corg is 20×10^-3-140×10^-3. Dark brown soil and its corresponding parent materials provide the source of Mo. It is concluded that the soil Mo is mainly derived from bedrock weathering.