摘要
以四川省泸州市碳酸盐岩和页岩分布区为研究区,开展了Se在成土母岩-根系土-水稻籽实体系中含量特征及迁移规律研究,丰富Se元素迁移转化理论,支撑服务富硒土地开发利用。研究结果表明,研究区页岩、根系土和水稻籽实Se含量分别为0.03~1.97 mg/kg、0.27~2.38 mg/kg和0.02~0.16 mg/kg,土壤硒以有机结合态(73%)和残渣态(25%)为主,有效态硒仅占0.69%。碳酸盐岩、根系土和水稻籽实Se含量分别为0.02~0.12 mg/kg、0.21~1.33 mg/kg和0.02~0.12 mg/kg,明显低于页岩区,土壤中有机结合态和残渣态硒所占比例高达97%,有效硒比例(1.58%)高于页岩区土壤。成土母岩的矿物组成和化学成分、Se含量及赋存形式对土壤性质和Se含量具有一定的控制作用。有机质、粘土矿物和pH值是土壤Se含量和生物有效性的主要控制因素。有机质和粘土矿物对硒的强烈吸附作用是研究区土壤富硒但生物有效性低的主要原因;pH值降低导致土壤胶体对硒的吸附能力升高,使土壤Se含量升高,但硒生物有效性随pH值降低明显降低。综上所述,研究区土壤Se含量高但生物有效性低,因此水稻籽实Se含量并不高,富硒土地的开发利用不能仅以土壤全Se含量作为判别标准,应结合土壤性质及硒生物有效性综合考虑。
The control factors of selenium content and migration rule in the parent rock-root soil-rice system in sedimentary rock areas(carbonate rock and shale)were studied to enrich the theory of selenium migration and transformation and further support the scientific utilization of selenium-rich land.The Se values of shale,corresponding soil and rice seed are 0.03~1.97 mg/kg,0.27~2.38 mg/kg and 0.02~0.16 mg/kg,respectively,and carbonate rock,soil and rice seed show Se content of 0.02~0.12 mg/kg,0.21~1.33 mg/kg and 0.02~0.12 mg/kg.The proportion of organic binding Se and residual Se in soil is up to 98%.The Se bioavailability of soil in shale area is 0.69%,which is lower than that in carbonate rock area(1.58%).The mineral and chemical compositions as well as content and modes of occurrence of Se in parent rocks play an important role in controlling physicochemical properties and Se content in soils.The content and bioavailability of Se in soil are predominantly controlled by soil pH and colloids.The strong adsorption of Se by organic matter and clay minerals is the main factor responsible for high content but low bioavailability of Se in soils.The decrease of pH results in the increase of Se adsorption by soil colloids and thus high Se content in soil.However,Se bioavailability shows a decrease trend with pH decreases.In summary,the soils in shale and carbonate rock areas show high content but low bioavailability of Se and consequently,low Se content in rice seed.Therefore,the total Se content in soils could not be regarded as the criterion for the exploration of Se-rich soil,and the soil properties and Se bioavailability should also be cautiously considered.
作者
刘秀金
杨柯
成杭新
唐世琪
郭飞
刘飞
LIU Xiujin;YANG Ke;CHENG Hangxin;TANG Shiqi;GUO Fei;LIU Fei(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,Hebei,China;Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth’s Critical Zone,Chinese Academy of Geological Sciences,Langfang 065000,Hebei,China;Research Center of Geochemical Survey and Assessment on Land Quality,China Geological Survey,Langfang 065000,Hebei,China)
出处
《地质通报》
CAS
CSCD
北大核心
2020年第12期1919-1931,共13页
Geological Bulletin of China
基金
中国地质调查局项目《全国土地质量地球化学调查成果集成与服务》(编号:DD20190518)
《全国土地质量综合监测与评价》(编号:DD20190527)。
