Premium
Direct determination of potassium‐calcium activity ratio in soils with two ion‐selective electrodes. I. Method of determination
Author(s) -
Yu T. R.,
Beyme B.,
Richter J.
Publication year - 1989
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19891520403
Subject(s) - potassium , chemistry , salt (chemistry) , calcium , electrode , soil water , suspension (topology) , sodium , analytical chemistry (journal) , chromatography , soil science , environmental science , organic chemistry , mathematics , homotopy , pure mathematics
A method for the direct determination of the potassium‐calcium activity ratio in soils with a potassium‐selective electrode and a calcium‐selective electrode was developed. The two electrodes were inserted into the soil suspension, and the potential difference was measured with a high‐impedance mV‐meter. The reproducibility of measurements was 2–3 mV, corresponding to 0.03–0.05 pK‐0.5pCa units. Measurements in soil paste and in supernatant clear solution gave identical results. The pK‐0.5pCa value varied only slightly with the variation in water to soil ratio or in salt concentration if the salt concentration was not high. At high salt concentrations, the value decreased.