Contribution of Humic Acid and a Polysaccharide to Water Repellency in Sand and Soil
1969
Savage, S. M. | Martin, J. P. | Letey, J.
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.
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