Contribution of Humic Acid and a Polysaccharide to Water Repellency in Sand and Soil1
- S. M. Savage,
- J. P. Martin and
- J. Letey2
A silica sand and Pachappa sandy loam were treated at various pH's with aqueous suspensions of three microbial humic acids, a soil and peat humic acid, a microbial polysaccharide, and metallic salts of the tested organic substances. Of all the substances tested, only one, a humic acid isolated from a Stachybotrys atra culture, caused water repellency in the sand and soil. The Fe3+ and Al3+ salts of this humic acid rendered the sand and soil practically impermeable to water. The organic matter content of the extremely water repellent sands was less than .05%. The final conclusion of the paper is that humic acid-like substances and polysaccharides probably do not contribute much to water repellency in soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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