Pilot Field Study on the Application of Seexcessive Bone Coal to Sedeficient Soil
低硒土壤增施高硒石煤的实验研究

Enshi city situated in the Exi Autonomous Pre- feature, Hubei, is the first Se-excessive area in China due to the local selenium-rich bone Coal origin. However, within the same prefecture, there are also some areas where the Se- deficient environment exists and an epidemic Keshan disease occurred. By applying the grannular bone coal with a mean selenium content of 100 mg/kg to those Se-deficient soils, the levels of selenium either in crops or in human body and animal show a significant dose-effect relation, resulting in not only the selenium supplement for human and animal but also an increase in crop output. Based on the recommended values for selenium in crops and hair of human in those areas where soils have a normal level of Selenium, it is suggested that it would be better to apply 15000-18000 kg/hm2 of bone coal to the Se-deficient soils in crops field. Moreover, the possible factors that make this measure available to increase crops output, and the duration during which this measure can keep the applied selenium available to crops, are also discussed.