A study was undertaken to determine some of
the factors which affected the extraction of sulphur from
seven selected soils of the Lower Fraser Valley and Vancouver
Island; with particular reference to the effect of pH,
concentration and cation of phosphate buffers. In all cases
the presence of phosphate resulted in more sulphur being
extracted, than extraction with water only. In every instance
increasing the concentration of neutral sodium phosphate
buffers from 0.005M to 0.5M resulted in increasing sulphur
extraction.
Using a 0.5H sodium phosphate buffer and increasing
the pH from 4 to 8 generally resulted in maximum extraction
at pH 7, except notably in the Langford soil in which the
amount of sulphur extracted increased as the pH was changed
from 4 to 8. The behaviour of four surface soils when
extracted with 0.5M sodium phosphate at varying pH levels
was quite similar, the mineralogy of the <2ยต fraction was
also similar.
Gel filtration studies of the 0.5M phosphate
extracts of the Langford showed that at pH 4 little inorganic
sulphate was extracted, while from pH 6 to 8, the amount
extracted remained almost constant, though more than three
times that extracted at pH 4. The extracted organic fraction
increased as the pH varied from 4 to 8. In soils with a low carbon content and a high
content of free iron and aluminum oxides, the water
extractable sulphur was very low, as was the amount of
phosphate extractable organic sulphate. The amount of
sulphate extracted from the original air dry samples by
0.5M phosphate was very much less than the sulphate adsorbed
from a 50 ppm sulphur solution.
It was found that a neutral 0.5M sodium phosphate
solution extracted more sulphur in nearly all cases, than
other extractants, and in the soils studied cold water did
not seem suitable. The neutral 0.5M phosphate solution
extracted inorganic and a portion of the organic sulphate
and may be expected to be a suitable chemical extractant
which will be able to indicate the sulphur status of soils
of the Lower Fraser Valley. / Land and Food Systems, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41846 |
| Date | January 1969 |
| Creators | Bart, Aldwyn Louis |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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