淹水条件下土壤硒迁移行为的研究Ⅱ.还原淋溶作用下土壤硒的迁移机理

Transport Behavior of Selenium in Soil under Waterlogging Ⅱ.Selenium Transport Mechanism in Soil under Reductive Leaching

对模拟土柱淋溶下的 1 5～ 2 0 ,35～ 45 ,75～ 85 cm土层土壤作各种形态硒含量测定 ,结果表明 ,淹水土壤硒的迁移主要受硒铁化合物还原淋溶机制控制 ,其次受富里酸键合硒淋溶及机械 (粘粒 )淋溶等机制的影响 ;外加的叶蛋白硒在土壤中分解成水溶性有机硒随水淋溶 ,少量以富里酸硒积累在中下层土壤 .Se6 + (Na2 Se O4)及 Se4+(Na2 Se O3)溶液经土柱淋溶 ,主要形成富里酸硒积累于土壤 ,且表土层积累率高于中下部土层 ,Se6 +积累又高于Se4+ .淋溶过程中 Se4+的迁移强度比 Se6

Thephysicalandchemicalpropertiesandvariousseleniumformsofdifferentsoillayers (15～20 cm, 35～45 cm and 75～85 cm) in modeling earth column are analysed in this paper.Selenium transport in waterlogged soil was primarily controlled by reductive leaching of seleniun iron compounds,and next by fumaric selenium leaching as well as mechanical leaching(or clay leaching). Added to soil,leafprotein selenium was decomposed into soluble organic selenium which was leached by water and was accumulated in the middle or lower part of soil in the form of fumaric selenium. Through earth column leaching, Se 6+ (Na 2SeO 4) and Se 4+ (Na 2SeO 3) primarily accumulated in soil in the form of fumaric selenium,and the accumulation ratio in upper layer was higher than that in middle or lower layer. Accumulation ratio of Se 6+ was higher than that of Se 4+ ,however,transport intensity of Se 4+ was stronger than that of Se 6+ .