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用~(75)SeO_2水溶液分别按0.131ppm和1.631ppm比例处理暗棕色森林土。用这种土壤盆栽的小麦含Se分别为0.023ppm和0.493ppm。小麦收获之后,对土壤残留的~(75)Se用不同的提取剂连续进行化学分级,~(75)Se的各种形态按其占土壤总Se的百分比大小排序为:同位素交换态Se>NH_4OH可提态Se>HNO_3可提态Se>HCl可提态硒>水溶态Se>K_2SO_4可提态硒。土壤残留~(75)Se主要以NaHSeO_3同位素交换态存在,其量占土壤总硒28%,NH_4OH可提态Se次之,占20%;水溶态Se较少,仅6—7%。以SeO_3~(-2)形式加入土壤的~(75)Se被土壤紧密吸附。
Dark brown forest soil was treated with ~ (75) SeO 2 aqueous solution at 0.131 ppm and 1.631 ppm, respectively. Seeds with this potted soil contained 0.023 ppm and 0.493 ppm Se, respectively. After the wheat was harvested, the ~ (75) Se residues in the soil were continuously chemically graded with different extractants. The morphology of ~ (75) Se was classified according to the percentage of total Se content in the soil as follows: isotopic exchangeable Se> NH 4 OH Available Se> HNO_3 Available Se> HCl Available Selenium> Water-soluble Se> K_2SO_4 Available Selenium. Soil residual 75 Se mainly exists as isotopic exchangeable NaHSeO 3, accounting for 28% of the total selenium in the soil. NH 4 OH can be used as secondary Se, accounting for 20% of the total. Se is only 6-7% less soluble in water. The Se (75) Se added to the soil as SeO_3 ~ (-2) is tightly adsorbed by the soil.