内蒙古鄂伦春旗土壤钼元素的分布特征及主要影响因素

钼元素是动植物生长必需的微量元素，生命体中的钼元素直接或间接来自土壤.依据内蒙古自治区鄂伦春旗东部主要耕地区1：25万土地质量地球化学调查项目所采集的土壤样品分析数据，对研究区内表层土壤钼含量进行了营养等级评价.鄂伦春旗东部地区土壤钼含量普遍达到丰富级以上.同时分析了地球化学指标、土壤类型、成土母质等对土壤钼含量的影响.认为钼含量在pH值为5～7之间时随pH增大而减小；在有机质含量20×10^-3～140×10^-3时，随有机质含量增加而减少.认为暗棕壤及其对应的成土母质为本区提供了钼的来源；提出了研究区内土壤钼主要来源于基岩风化的结论.

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.