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Norvell用改进EDTA法测定了土壤中Zn~(2+)、Cu~(2+)和Mn~(2+)的离子活度以及EDTA与Ca、Mg螯合配位体的相互影响。在Zn-EDTA系统中,CaL~(2-)+MgL~(2-)平衡摩尔个数随土壤溶液pH增加而加大,导致了金属离子浓度的减低。基于pH和金属离子有着关联性,从而就pM+2pOH(M表示Zn、Cu或Mn)讨论过碱性和石灰性土壤中各种氧化物、氢氧化物、碳酸盐、硫化物和未知的“土壤固相”对Zn~(2+)、Cu~(2+)和Mn~(2+)离子活度的调节作用。
Norvell’s modified EDTA method was used to determine the ion activities of Zn 2+, Cu 2+ and Mn 2+ in soil and the interaction between EDTA and Ca and Mg chelating ligands. In Zn-EDTA system, the equilibrium molar number of CaL ~ (2-) + MgL ~ (2-) increased with the increase of soil solution pH, resulting in the decrease of metal ion concentration. Based on the correlation of pH with metal ions, various oxides, hydroxides, carbonates, sulfides and the unknown oxides in alkaline and calcareous soils are discussed in terms of pM + 2 pOH (M stands for Zn, Cu or Mn) Regulation of Soil Solid Phase on the Activities of Zn ~ (2 +), Cu ~ (2+) and Mn ~ (2+) Ions.