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Wildfire Effects on Soil Nutrients and Leaching in a Tahoe Basin Watershed
Author(s) -
Murphy J. D.,
Johnson D. W.,
Miller W. W.,
Walker R. F.,
Carroll E. F.,
Blank R. R.
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0144
Subject(s) - watershed , environmental science , leaching (pedology) , nutrient , hydrology (agriculture) , structural basin , soil nutrients , environmental engineering , soil water , soil science , geology , ecology , geotechnical engineering , machine learning , computer science , paleontology , biology
ABSTRACT A wildfire burned through a previously sampled research site, allowing pre‐ and post‐burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post‐fire erosion caused large and statistically significant ( P ≤ 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water‐extractable SO 4 2− in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca 2+ in most horizons, but no consistent or statistically significant effects on exchangeable K + or Mg 2+ , or on Bray‐, bicarbonate‐, or water‐extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH 4 + , NO 3 − , ortho‐P, and (especially) SO 4 2− were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH 4 + and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short‐term effects of wildfire were on leaching whereas the major long‐term effect was the loss of N from the forest floor and soil during the fire.