Journal of Resources and Ecology ›› 2018, Vol. 9 ›› Issue (5): 545-553.DOI: 10.5814/j.issn.1674-764x.2018.05.012

• Resources and Ecology in the Qinghai-Tibet Plateau • Previous Articles     Next Articles

Geographical and Botanical Variation in Concentrations of Molybdenum in Natural Pasture Plants and Surface Water and Yak Molybdenum Ingestion in North Tibet, China

TIAN Yuan1,2, YU Chengqun1,*, ZHA Xinjie2,3, WU Jianshuang1, GAO Xing3, FENG Chujian4,*   

  1. 1. Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    4. Ministry of Science and Technology of the People’s Republic of China, Beijing 100862, China;
  • Received:2018-03-10 Revised:2018-07-05 Online:2018-09-30 Published:2018-09-30
  • Contact: * YU Chengqun, E-mail: yucq@igsnrr.ac.cn; FENG Chujian, E-mail: fengchujian@126.com
  • Supported by:
    Key Science and Technology Research Program of Tibet (ZDZX2017000122, XZ201801NA02); Natural Science Foundation of Tibet (2016ZR-15-76); Key Science and Technology Research Program of Tibet (Z2016C01G01).

Abstract: The North Tibet plateau is the world highest plateau with a unique alpine grassland and water environment. To obtain a better understanding of the correct supply of Molybdenum (Mo) to livestock in north Tibet, we investigated the content and geographical variation of Mo in different families of pasture plants (n=1017) and water (n=40), then discuss the Cuprum (Cu):Mo ratio in different plant families, and calculate the total Mo intake of the yak in north Tibet. The average Mo concentration in five families preferred for grazing are: Compositae (2.71 μg g-1), Leguminosae (2.70 μg g-1), Gramineae (2.48 μg g-1), Cyperaceae (1.63 μg g-1), and Rosaceae (1.51 μg g-1). There was a strong geographical variation in Mo concentration (p < 0.001). The mean value of Mo in north Tibet surface water from 15 sites is 0.89 µg L-1. The Mo ingestion by yak through these plants and water in north Tibet is about 9586 µg day-1 which means the toxicity of Mo does not exist in the average daily diet. However, the large geographical variation found may cause some toxicity of Mo in the average daily intake of north Tibet pasture plants in some areas. The Cu:Mo ratio of 2:60 is considered the limit for risk of Mo hyperactivity, while extremely high Cu:Mo ratios may lead to chronic copper poisoning. Our survey of plant samples found 43.29% below and 29.3% above the limiting Cu:Mo ratio of 60 indicating some risk to north Tibet livestock.

Key words: copper, molybdenum, North Tibet, pasture plants, water