A comparison of electro-ultrafiltration and quantity/intensity measurements of soil potassium with its uptake by ryegrass in Scottish soils
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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 wordsEUF-K Exchangeable K Fluvioglacial sand Glasshouse Lower Old Red Sandstone till Perennial ryegrass Q/I-K Quartz-mica-schist
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- 1.Addiscott T M 1970 The potassium Q/I relationships of soils given different manuring. J. Agric. Sci. Camb. 74, 131–137.Google Scholar
- 2.Beckett P H T 1965 Activity coefficients for studies on soil potassium. Agrochimica 9, 150–154.Google Scholar
- 3.Beckett P H T 1967 Potassium potentialsIn Soil Potassium and Magnesium. Techn. Bull. Ministry of Agriculture, Fisheries and Food 14, 32–37.Google Scholar
- 4.Beckett P H T 1972 Critical cation activity ratios. Adv. Agron. 24, 379–412.Google Scholar
- 5.Grimme H 1980 The effect of field strength on the quantity of K desorbed from soils by electro-ultrafiltration. Z. Pflanzenernaehr. Bodenkd. 143, 98–106.Google Scholar
- 6.Jackson M L 1958 Exchangeable metallic cation determinations for soils.In Soil Chemical Analysis. Constable, London pp 82–110.Google Scholar
- 7.Nair P K R and Grimme H 1979 Q/I relations and electroultrafiltration of soils as measures of potassium availability to plants. Z. Pflanzenernaehr. Bodenkd., 142, 87–94.Google Scholar
- 8.Németh K 1972 The determination of desorption and solubility rates of nutrients in the soil by means of electroultrafiltration (EUF). Proceedings of the 9th Coloquium of the International Potash Institute. pp 171–180.Google Scholar
- 10.Németh K 1976 The determination of effective and potential availability of nutrients in the soil by means of electroultrafiltration. Appl. Sci Developm 8, 89–111.Google Scholar
- 11.Németh K 1979 The availability of nutrients in the soil as determined by electro-ultrafiltration (EUF). Adv. Agron. 31, 155–188.Google Scholar
- 12.Németh K and Forster H 1976 Beziehungen zwischen Ertrag und K-entzug von Ackerbohnen (Vicia faba) sowie verschiedenen K-fraktionen von Böden. Bodenkultur 27, 117–119.Google Scholar
- 13.Sinclair A H 1979 Availability of potassium to ryegrass from Scottish soils 1. Effects of intensive cropping on potassium parameters. J. Soil Sci. 30, 757–773.Google Scholar
- 14.Sinclair A H 1979 Availability of potassium to ryegrass from Scottish soils II. Uptake of initially non-exchangeable potassium. J. Soil Sci. 30, 775–783.Google Scholar
- 15.Sinclair A H 1980 Desorption of cations from Scottish soils by electro-ultrafiltration. J. Sci Food Agric. 31, 532–540.Google Scholar