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<br />McGhie, D.A., and Posner, A.M., 1980, Water repellence of a heavy-textured Western <br />Australian surface soil: Australian Journal of Soil Research, v. 18, p. 309-323. <br />This study evaluated the degree and cause of water repellency in virgin mallet hill soil near <br />Narrogin, Western Austtalia. The occurrence of water repellency in this case was unusual, <br />since the soils contained more than 20% clay. The authors attributed this anomaly to the <br />presence of clay aggregates in the soil, which allowed water repellency to persist, despite the <br />texture. Results of the investigation indicated that severe water repellency only developed <br />where litter was present. Fungi (Aspergillus and Penicillium), however, did not contribute to <br />water repellency, and in some instances, appeared to decrease it. Extractions with aqueous <br />solvents removed water repellency, while subsequent treatments with non-polar solvents <br />restored it. <br /> <br />McGhie, D.A., and Posner, A.M., 1981, The effect of plant top material on the water <br />repellence of fired sands and water repellent soils: Australian Journal of <br />Agricultural Research, v. 32, p. 609-620. <br />This study examined the effects of a variety of soil amendments on the water repellency of <br />fired sands. Researchers evaluated a range of finely ground plant species, suites of fungal <br />cultures, and different crop and pasture rotations. Results indicated that cereal crops tended <br />to reduce repellency, and that continuous pasture led to severe repellency. The authors <br />suggest that growing wettable species in water-repellent areas may be one option to help <br />reduce water repellency in the soil. <br /> <br />McNabb, D.H., Gaweda, F., Froehlich, H.A., 1989, Infiltration, water repellency, and <br />soil moisture content after broadcast burning a forest site in southwest <br />Oregon: Journal of Soil and Water Conservation, v. 44, no. 1, p. 87-90. <br />This paper describes the results of broadcast burning of a harvested site in a Mixed <br />Evergreen Forest Zone of the eastern Siskiyou Mountains in southwest Oregon. Parent <br />material is loam or fine-textured soil. Increased water repellency was observed for a period <br />of fIve months after the bum. The water repellency then decreased rapidly as fall rains <br />recharged the soil prof1le. Measuring water repellency by apparent contact angle produced a <br />closer correlation with change in infiltration capacity than did the water-drop-penetration- <br />time test in the fIeld. Water repellency measured using the water-drop-penetration-time test <br />gradually declined after burning. But when measured using the contact-angle method, water <br />repellency increased slightly during the summer. A relation between the apparent contact <br />angle and fIeld moisture content is defined. These workers also concluded that because even <br />decreased inf1ltration capacity due to water repellency is still two to three times greater than <br />that which would occur in a 1 DO-year storm, the potential for broadcast burning to result in <br />overland flow from intense, short-duration storms is low. Prolonged storms of low intensity <br />which locally saturate the soil prof11e are more likely to result in overland flow in a broadcast <br />burn area. <br /> <br />27 <br />