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Plant uptake of exchangeable and non‐exchangeable potassium. I. Measurement and modelling for onion roots in a Chalky Boulder Clay soil
Author(s) -
MITSIOS I. K.,
ROWELL D. L.
Publication year - 1987
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1987.tb02122.x
Subject(s) - permanent wilting point , chemistry , potassium , wilting , field capacity , plant roots , soil water , clay soil , soil science , horticulture , botany , environmental science , biology , organic chemistry
SUMMARY Uptake of K was measured using a single onion root technique with four soil cylinder diameters, and measuring changes in exchangeable K in the soil. Baldwin's model fitted the measured uptake when only exchangeable K was taken up, but that of Heming & Rowell allowed predictions of uptake of both exchangeable and non‐exchangeable K (K nes ) after fitting the necessary parameters. Release of K nex occurred in both 3 mm and 6 mm cells (root densities of 14cm cm” −3 and 3.5 cm cm −3 ) in 10 days. Predictions were made for longer times and differing soil water contents: after four weeks at a water content midway between field capacity and wilting point the contribution of K nex to total uptake was significant (up to 60%) for plants with high root densities.