Desorption of cations from scottish soils by electro‐ultrafiltration

Alex H. Sinclair*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

9 Citations (Scopus)


Soil cations were desorbed by electro‐ultrafiltration (EUF), i.e. by applying an external electric field to aqueous suspensions, and collecting the cations by ultrafiltration. Three different field strengths were used to obtain several cation fractions in a single extraction run lasting 35 min. Potassium desorbed in 10 min (K10) was closely correlated with the equilibrium activity ratio (AR0) of soil K measured in 0.01M CaCl2, for all but the sandy loam soils, while that desorbed in 35 min (K35) was less than the exchangeable K, but correlated closely with it. EUF values compared favourably with other soil K parameters, determined by conventional methods, for predicting uptake of K by rye‐grass from ten soils during intensive cropping in the glasshouse. Sodium desorbed in 35 min (Na35) approximated to the exchangeable Na, although most of it was desorbed in the first 15 min. Na10 and Na35 accounted for about 56% of the variation in Na uptake by ryegrass at the first cut, and 68% of the variation in the cumulative uptake at the sixth cut. Between 9–24% of the exchangeable calcium was desorbed in 35 min, and magnesium desorbed was closely correlated with both the Mg concentration of the soil saturation extract and the exchangeable Mg. EUF extraction of Mg is less satisfactory than for K, Na and Ca owing to the precipitation of Mg(OH)2 on the cathode filter.

Original languageEnglish
Pages (from-to)532-540
Number of pages9
JournalJournal of the Science of Food and Agriculture
Issue number6
Publication statusPrint publication - Jun 1980
Externally publishedYes


Dive into the research topics of 'Desorption of cations from scottish soils by electro‐ultrafiltration'. Together they form a unique fingerprint.

Cite this