土壤中硒含量、形态及有效性分析

近年来,硒(Se)对于植物以及人体的有效性逐渐得到重视,越来越多的富硒土壤被发现和利用,但目前人们对于土壤中硒的含量、形态、转化及其有效性还没有形成系统、全面和准确的认识。本文通过对国内外硒研究文献的整理和分析,认为当前对土壤中硒总量有较全面的数据,但对于硒的植物有效性与其他影响因素之间的关系认识不一,主要原因在于研究前提(土壤类型、气候等)的差异以及不同因素之间的掩盖。今后应在相对控制某一变量的前提下,采用定量模型技术,分析土壤硒有效性的真实影响因素和定量规律。在区域大气-土壤-水-植物系统的硒平衡方面,针对大气沉降、硒甲基化(挥发)、硒的淋失等途径的定量规律和影响因素,应开展大尺度范围的监测和分析。利用硒同位素技术(自然丰度和加富标记),更加准确地追踪硒在土壤、植物等子系统的转化规律,从而为提高硒的利用效率提供科学依据。

Review on the Content,Specification of Selenium and Its Availability in Soils

As more selenium(Se)rich soil has been found, people begin to give more attention to the availability of Se for plant and humanbeings. However, current understanding for the content, specification and plant availability is not complete and accurate. By analyzing the past research on Se in soils, we believed that differences in backgrounds(soil types, climate)and hiding effect of various influential factors led to different results with regard to the relationship of soil Se with influential factors. There should be more controlled study and quantitativebased model to trace the genuine relationship between soil Se and Fe and Al oxide, p H, Eh and organic matter. For the regional Se balance within air-soil-water-plant system, air precipitation, Se volatilization and leaching should be more precisely monitored. Isotope technology(natural istotope and labelling)could be a good option for tracing transformation mechanisms of Se in soil-plant system and this would give more good scientific support for the increasing Se utilization efficiency.