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<br />Hubbel, D.H., 1988, Developmental aspects of water-repellency of sandy soils: Soil
<br />Science Society of America Journal, v. 52, p. 1512-1514.
<br />In contrast to studies where water-repellent soils were reported to break down under wet
<br />conditions, this paper described the occurrence of a water-repellent soil in which repellency
<br />(related to microbial growth) was intensifIed by high hwnidity conditions. The investigation
<br />originally attempted to transfer the latter form of repellency from a water-repellent, Florida
<br />sand, to other wettable materials. Direct contact between materials was ineffective in
<br />transfetring repellency. During the course of the experiment, researchers discovered that
<br />repellency was actually suppressed when another variety of Florida soil (Eustis fIne sand)
<br />was mixed with the repellent sand. This elicited another investigation into the mechanism of
<br />suppression, which determined that an organism (apparently a Bacillus species) in the Eustis
<br />sand produced a volatile product capable of suppressing the water repellency.
<br />
<br />Hudson, R.A., Traina, S.J., Shane, W.W., 1994, Organic matter comparison of
<br />wettable and nonwettable soils from bentgrass sand greens: Soil Science
<br />Society of America Journal, v. 58, no. 2, p. 361-366.
<br />Unlike previous studies that have only analyzed organic matter associated with water-
<br />repellent soils, this research included organic matter analysis of wettable soils from the same
<br />site. Researchers compared the alltaline extractable and lipid fractions of wettable and
<br />nonwettable soils from creeping bentgrass sand greens. Soil samples of each type were taken
<br />from two sites and subjected to a series of extraction sequences. At the fIrst site, the
<br />hydrophobicity appeared to be the result of physical or structural differences, rather than
<br />differences in organic matter. However, methanol extractions on samples from the second
<br />site did reveal the presence of some qualitative differences. The introduction includes a
<br />literature review of previous research on the nature of hydrophobic substances.
<br />
<br />Hussain, S.B., Skau, C.M., Bashir, S.M., and Meeuwig, R.O., 1969, Infiltrometer
<br />studies of water-repellent soils on the east slope of the Sierra Nevada, in
<br />DeBano, L.F., and Letey, John, eds., Water-repellent soils: University of
<br />California, Riverside, May 6-10, 1968, Proceedings, p. 127-131.
<br />Simulated rainfall experiments were used to evaluate runoff with respect to various soil
<br />characteristics (e.g. initial soil moisture, bulk density, and organic matter), and six different
<br />cover treatments. The study area, located approximately 20 miles south of Reno, Nevada,
<br />was dominated by gravely-loamy sands, and covered by chaparral vegetation and stands of
<br />pine. Researchers found that pine litter signifIcantly decreased wettability of the soil.
<br />However, they found that although the pine litter imparred water repellency to the soil, it
<br />also appeared to result in a better-structured soil, capable of holding more moisture. As
<br />many other researchers have found, burning caused a water repellent layer to form below the
<br />surface, leaving a wettable layer on top. The burned plots exhibited higher bulk densities
<br />than plots where pine litter had been manually removed from the surface. Despite this
<br />characteristic, the burned plots still had higher rainfall retention.
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