基于有效硒的富硒土壤阈值及有效硒的影响因素

Threshold of Se-rich Soil Based on Available-Se and Influencing Factors of Available-Se

土壤中有效硒(Se)含量是影响作物硒含量的主导因素.为合理有效在有效硒含量高、全硒含量低的土壤中圈定富Se土壤范围并提出天然富Se作物培育理论性指导,在宁夏北部石嘴山市采集表层土壤样品8814件和根系土-作物配套样品195件,以有效硒为分析主线,通过对表层土壤和根系土中全Se、有效Se含量和Se形态以及根系土配套作物硒含量的综合研究,确定适合研究区的基于有效Se的富Se土壤阈值,建立有效Se的多元回归模型确定影响有效Se的主要理化指标以期通过提高有效硒的方式提高作物富硒率.结果表明,根系土-作物中Se的特征可代表表层土壤全Se和有效Se特征,根系土全Se、有效Se及作物Se含量的协调性分析确定0.24mg·kg^(-1)的全Se含量作为富Se土壤界定阈值;有效Se的多元回归模型显示,土壤中全Se和土壤肥力元素含量的增加可促进有效Se的富集.

Available selenium(Se)in soil was the predominant factor affecting the content of Se in crops.In order to reasonably delineate the Se-rich soil range and propose theoretical guidance for the cultivation of natural Se-rich crops in a region where the surface soils had a high level of available-Se and a low level of total-Se,8814 samples in surface soil and 195 root-crop matching samples were collected in Shizuishan in northern Ningxia.On the basis of the main line of analysis of available-Se,the following research was conducted:by synthetically studying the total-Se and available-Se in surface soil and root soil,the morphology of Se in surface soil,as well as Se in crops,deep and coordinated analyses of content among total-Se,available-Se,and Se in root-crop matching samples were carried out,and the suitable threshold for Shizuishan was confirmed.A multiple regression model of available-Se was established to determine the main physical and chemical indexes affecting available-Se,which were expected to improve the Se enrichment rate of crops through the enhancement of available-Se.The results demonstrated thatω(Se)andω(Se_(available))in the surface soil in Shizuishan were 0.26 mg·kg^(-1)and 12.85μg·kg^(-1),respectively,and the characteristics of Se and available-Se in root-crop matching samples could represent those in surface soil.Thus,it was recommended to use 0.24 mg·kg^(-1)as the suitable threshold of Se-rich soil.The multiple regression model of available-Se showed that the increase in total-Se and soil elements affecting soil fertility could promote the enrichment of available-Se.