黑龙江拜泉地区硒元素在土壤-植物系统中的迁移富集规律

MIGRATION AND ENRICHMENT OF SELENIUM IN SOIL-PLANT SYSTEM IN BAIQUAN AREA, HEILONGJIANG PROVINCE

以拜泉地区1∶5万土地质量地球化学调查数据为基础,开展硒地球化学特征及生态效应研究,探讨硒元素在土壤-植物系统中的迁移富集规律.研究表明:拜泉地区根系土硒含量均值为0.25×10^(-6),属中等富硒土壤,黄豆和水稻富硒占比相对较高;水溶态硒和离子交换态硒含量之和约为5%,一定程度上制约硒的有效量.土壤理化性质对硒全量、硒形态及其迁移富集具有重要影响:碱性—中性土壤硒含量基本不受pH制约,硒多以亚硒酸盐形式存在,不利于硒元素的转移和植物吸收;硒全量(有效量)与有机质呈显著正相关关系,但有机质含量超过某一界限后,有机质含量的增加虽然可以提高硒含量水平,但也抑制硒元素的迁移富集.

Based on the 1∶50000 land quality geochemical survey data of Baiquan area in Heilongjiang Province,the paper studies the geochemical characteristics and ecological effects of selenium(Se),and discusses the migration and enrichment rule of Se in soil-plant system.The results show that the Se content in root soil is averagely 0.25×10^(-6),belonging to medium Se-rich soil,with higher Se-rich percentage in soybean and rice.The Se contents in water-soluble and ion-exchangeable forms together account for about 5%,which restricts the available content of Se to some extent.The physicochemical properties of soil have important effect on total Se,Se forms and migration-enrichment.Specifically,Se content in alkaline-neutral soil is not affected by pH,mainly existing in the form of selenite,which is not conducive to the transfer of Se and plant absorption.The total Se(available content)is positively correlated with organic matter.However,when the content of organic matter exceeds a certain limit,its increase can improve the Se content,but also inhibit the migration and enrichment of Se.