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Rapid methods for assessing the P and K status of soils
Author(s) -
Hunt John,
Barnes Anthony,
Greenwood Duncan J.
Publication year - 1976
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740270911
Subject(s) - soil water , reagent , soil test , filtration (mathematics) , environmental science , chemistry , mathematics , chromatography , soil science , statistics
Standard laboratory procedures for measuring soil P and soil K were modified to provide rapid methods that required only the simplest equipment and no laboratory. These methods involved shaking soil for only 1 min with extractant, the use of a novel filtration technique, the presentation of reagents in tablet form and the estimation of concentration by visual comparison of colour intensity. Experiments on 71 different soils showed that the amounts of P and K extracted by shaking with reagents for only 1 min were always very highly correlated with the amounts extracted by shaking for 30 min as in the standard laboratory procedures. The error introduced by assessing colour visually was only small compared with that due to sampling of the field. Analysis of the errors showed that the accuracy in determining the P and K status of a field soil by the rapid methods was only slightly less than those for the laboratory procedures provided five times as many analyses per field were carried out.