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GAMMA RADIATION FOR MEASURING WATER CONTENTS IN SOIL COLUMNS WITH CHANGING BULK DENSITY
Author(s) -
OLESEN S. E.
Publication year - 1973
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.1365-2389.1973.tb02313.x
Subject(s) - loam , water content , bulk density , attenuation , radiation , content (measure theory) , soil science , density of air , soil water , water retention curve , materials science , analytical chemistry (journal) , mathematics , chemistry , optics , environmental science , physics , mathematical analysis , thermodynamics , water retention , geology , environmental chemistry , geotechnical engineering
Summary Water profiles in soil columns were measured by the single‐source gamma radiation method. Together with the normal attenuation equation, linear or parabolic equations for the relation between bulk density and volumetric water content were used. To compensate for moderate changes in the bulk density during the experiment both initial and final bulk density and the water content were used in the water profile estimations. For a sandy loam soil, the radiation method without any corrections for bulk density changes resulted in a mean error of the volumetric water content estimation of 0.035 cm 3 cm −3 , when the water content changed from 0.35 to 0.15 cm 3 cm −3 . By correction for changing bulk density by means of a linear or a parabolic equation the maximum difference between real and estimated water content was 0.009 and 0.002 cm 3 cm −3 , respectively. Applying the latter method and a count of 10 5 the error of a single water content measurement was 0–004 cm 3 cm −3 .