西藏山南市乃东区土壤硒分布特征及影响因素

硒是动物和人体所必需的微量元素之一,其丰缺与人和动植物的健康有着密切关系。近年来研究成果表明西藏缺硒土壤主要分布在雅鲁藏布江(简称“雅江”)以北地区,而雅江以南存在土壤全硒含量较高且面积较大区域。西藏山南市乃东区位于青藏高原中南部雅江流域,为雅鲁藏布江流域重要的农业区,也是西藏粮仓之一。本文以西藏山南市乃东区为研究对象,采用原子荧光光谱法(AFS)等方法测定了研究区1022件表层土壤、30组青稞籽实样及根系土壤样品中的硒等元素含量;同时对西藏山南市乃东区雅江两侧农用地及周边牧草地、林地表层土壤硒的分布特征和影响因素进行了研究。结果表明：雅江北侧土壤硒含量算术平均值为0.14mg/kg,接近西藏土壤硒含量平均值0.15mg/kg;雅江南侧土壤硒含量算术平均值为0.30mg/kg,高于西藏土壤硒含量平均值的一倍,略高于中国土壤硒含量平均值0.29mg/kg。乃东调查区不同土地利用类型土壤硒含量的平均值由大到小为：耕地(0.24mg/kg)>牧草地(0.22mg/kg)>林地(0.19mg/kg)。研究结果显示乃东调查区雅江两侧土壤硒含量差异较大;土壤硒元素含量除了受地质背景影响...

Distribution Characteristics and Influencing Factors of Soil Selenium in Naidong District, Shannan City, Tibet

BACKGROUND: Selenium is one of the essential trace elements for animals and humans, and its abundance is closely related to the health of humans, animals and plants. Selenium deficiency is common in Chinese soil, especially in Tibet. Research results in recent years have shown that the selenium-deficient soils in Tibet are mainly distributed in the north of the Yarlung Zangbo River (referred to as "Yajiang"), while there are areas with high total selenium content and a large area in the south of the Yajiang River. Naidong district is located in the Yajiang River valley in the central and southern parts of the Tibet Plateau. It is one of the important agricultural areas in Tibet and one of the granaries of Tibet.OBJECTIVES: To investigate the distribution characteristics and influencing factors of soil selenium in different areas and different land utilization types on both sides of the Yajiang River in Naidong District, Shannan City, Tibet.METHODS: The contents of selenium and other elements in 1022 topsoil, 30 groups of highland barley seed samples and root soil samples in the Naidong District were determined by atomic fluorescence spectrometry (AFS). Correlation analysis was used to study the influencing factors of soil selenium.RESULTS: The data showed that the arithmetic mean of selenium content in the soil on the north side of the Yajiang River was 0.14mg/kg, which was close to the mean value of selenium in the soil of Tibet (0.15mg/kg). The arithmetic mean of selenium content in the soil on the southern side of the Yajiang River was 0.30mg/kg, which was twice the mean value of soil selenium content in Tibet, and slightly higher than the mean soil selenium content in China (0.29mg/kg). The average selenium content in different land utilization types in the Naidong survey area was cultivated land (0.24mg/kg)>pasture land (0.22mg/kg)>forest land (0.19mg/kg). The research results showed that the soil selenium content on both sides of the Yajiang River in the Naidong survey area was quite different, and there was selenium-rich soil on the south side of the Yajiang River. The factors controlling soil selenium content were not only affected by geological background, but also related to soil pH, organic matter and other factors. Soil Se content increased significantly with the increase of soil organic matter content, but decreased with the increase of soil pH.CONCLUSIONS: It is suggested to make full use of the selenium-enriched soil in Naidong District, and study the absorption of selenium by different crops to improve the availability of selenium in the soil through farmland nutrient management, and promote the development of the local selenium-enriched industry.