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<br />DeBano, L.F., 1969c., Th,~ relationship between heat treatment and wate:r repellency
<br />in soils: in DeBano, L.11., and Letey,John, eds., Water-r~pellent soils:
<br />University of California, Hive:rside, May 6-10, 1968, Proc,~edings, !p. 265-279.
<br />This paper descriDes the results of two types of burning experiment: that were used to study
<br />the relationship between water repellency in brushland soils ani I heat tteatment. The
<br />expetiments lead the authors to p::opose a model for water repell ,ncy before, during and
<br />after fire. Before fire, hydrophobic substances accumulate in the liter layer and mineral soil
<br />immediately beneath it. \1ilhen th~ fire burns the vegetation littel layer, the hydrophobic
<br />substances move downward along temperature gradients. After the fIre, a water-repellent
<br />layer is located below and paralle.. to the soil surface on the burned a rea.
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<br />DeBano, L.F., 1971, The e:ffect of hydrophobic substances on" ater movement in soil
<br />during infiltration: Soil Sdence Society of America Proceedings, v. 35, no. 2,
<br />p. 340-343.
<br />Inf1ltration experiments were concluw:d on wettable and water-re pellent soils using both
<br />vertical and horizontal soil columns. Soil samples were collected from the San Gabriel
<br />Mountains of southern Ca!ifornii, from a burned area that had formerly been covered with
<br />chaparral vegetation. Results showed that hydrophobic substanc es signifIcantly reduced
<br />inf1ltration, especially at the lower water contents. Repellent soils hid horizontal inf1ltration
<br />rates that were 25 times slower t:latl those in wettable soils, and mc re diffuse wetting fronts
<br />with signifIcantly lower water contents.
<br />
<br />DeBano, L.F., 1981, Water repell,mt soils: a state-of-the art: Pa:ific Southwest Forest
<br />and Range Experiment Station, Berkeley, Calif., V.S.D..<\.. Forest Service
<br />General Technical Report PSW-46, 21 p.
<br />This paper provides a comprehen:;ive overvi.ew of water-repellent soils that addresses the
<br />distribution, chemistry, effects on wa'ter movement, and classifIcation (me:asurement) of
<br />warer repellency, as well as the factors that affect it. The benefIts, problems, and research
<br />needs of water repellency are al:;o addressed. For each topic, the author includes a
<br />discussion of previous research, and concludes with current knowleccge of the subject.
<br />
<br />DeBano, L.F., and Krammes, J.S., 1966, Water-repellent soils a:ld their relation to
<br />wildfire temperatures: Bulletin of the International Ass, )ciation of Scientific
<br />Hydrology, v. 11, no. 2, p. 14-:l9.
<br />A previous (1965) paper by the :;ame authors is one of the first to :Iescribe the relationship
<br />between fire and soil-water repellency. As part of an ongoing investigation, this study
<br />attempted to determine the sigmfIcance of temperature and duration of healing. Naturally
<br />water-repellent soil samples were collected from the San Gabriel Mountains of Southern
<br />California, and heated between 3000F and 9000F for up to 20 nllutes. Intense water
<br />repellency resulted from the rnider treatments, whereas extreme 1 emperatures (800-900oF
<br />applied for 20 minutes) completely destroyed repellency. Although these experiments' did
<br />not realistically simulate natural conditions (samples were heated ir a muffle furnace rather
<br />than from the surface, as would occur in a forest fire), the results stil provided some data on
<br />time-temperature relationships, and confirmed the role of heating in some forms of water
<br />repellency.
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