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Soil Wettability and Fire in Arizona Chaparral
Author(s) -
Scholl David G.
Publication year - 1975
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1975.03615995003900020033x
Subject(s) - chaparral , environmental science , soil water , water repellent , wetting , volatilisation , organic matter , environmental chemistry , chemistry , soil science , materials science , ecology , composite material , organic chemistry , biology
Soils on typical Arizona chaparral sites showed water repellence both before and after fire. Both field and laboratory fires caused major changes in the water repellency of four natural soil layers. Relatively cool fires caused water repellence in the surface layer, while hot fires produced repellence at a greater depth. Under hot fires, however, the surface layer was rendered completely wettable. By measuring the wetting angle of soil layers from progressively hotter fires, it was possible to pinpoint temperatures where water‐repellent layers are first formed and then destroyed. Organic matter decreased at the progressively higher temperatures. Volatilization and subsequent loss to the atmosphere are believed an important part of this loss of organic matter. The volatilized material causing water repellence is almost completely lost above 270C. Below this temperature, sufficient material is trapped and condensed on exchange sites to produce water repellence.