Plant and Soil

, Volume 64, Issue 1, pp 85–94 | Cite as

A comparison of electro-ultrafiltration and quantity/intensity measurements of soil potassium with its uptake by ryegrass in Scottish soils

  • A. H. Sinclair


Electro-ultrafiltration (EUF) and quantity/intensity (Q/I) parameters of soil K were compared for 14 soils from each of three soil series. The K desorbed by EUF during the first 10 min (K10) was closely correlated with the equilibrium activity ratio (AR0) for soils of the same series, but differences between series reflected the soil K-buffering capacity, indicating that K10 includes loosely held exchangeable K and is not strictly an intensity measurement.

EUF values were compared with conventional soil test methods for predicting K-uptake and dry-matter yield of ryegrass grown in the glasshouse. Correlation coefficients between K uptake at the first cut were 0.80 for K10, 0.88 for Ka (the initially labile K derived from the Q/I curve), 0.92 for K35 (desorbed by EUF in 35 min) and 0.97 for Kex (1.0M ammonium acetate extraction).

Key words

EUF-K Exchangeable K Fluvioglacial sand Glasshouse Lower Old Red Sandstone till Perennial ryegrass Q/I-K Quartz-mica-schist 


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Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1982

Authors and Affiliations

  • A. H. Sinclair
    • 1
  1. 1.The Macaulay Institute for Soil ResearchAberdeenScotland

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