Nine soils with distince properties and Se levels were selected to test a fractionation procedure of soil Se based on sequential extraction.Soil Se was fractionated into readily available Se(fraction I,extracted by 0....Nine soils with distince properties and Se levels were selected to test a fractionation procedure of soil Se based on sequential extraction.Soil Se was fractionated into readily available Se(fraction I,extracted by 0.5 M NaHCO3),slowly available Se(fraction II,extracted by 0.1 M NaOH-0.1 M Na4P2O7),amorphous oxide-occluded Se(fraction Ⅲ,extracted by acid ammonium oxalate)free oxide-occluded Se (fraction VI,extracted by dithionite-citrate-bicarbonate buffer solution)and residual Se(fraction V,determined by NHO3-HClO4 digestion of the final soil residue).The recovery of soil Se(the sum of all fractions over total soil Se determined independently)by this procedure was from 88.1% to 110.9%,mean 99.2%±6.4% for the test soils.The sum of fractions I and II,provided a good measure of available Se in soils and the percentage of fraction I plus II over the total soil Se,tentatively defined as Se availability index.could be used to indicate soil Se status and predict Se deficiency.展开更多
文摘Nine soils with distince properties and Se levels were selected to test a fractionation procedure of soil Se based on sequential extraction.Soil Se was fractionated into readily available Se(fraction I,extracted by 0.5 M NaHCO3),slowly available Se(fraction II,extracted by 0.1 M NaOH-0.1 M Na4P2O7),amorphous oxide-occluded Se(fraction Ⅲ,extracted by acid ammonium oxalate)free oxide-occluded Se (fraction VI,extracted by dithionite-citrate-bicarbonate buffer solution)and residual Se(fraction V,determined by NHO3-HClO4 digestion of the final soil residue).The recovery of soil Se(the sum of all fractions over total soil Se determined independently)by this procedure was from 88.1% to 110.9%,mean 99.2%±6.4% for the test soils.The sum of fractions I and II,provided a good measure of available Se in soils and the percentage of fraction I plus II over the total soil Se,tentatively defined as Se availability index.could be used to indicate soil Se status and predict Se deficiency.
