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Soil Development on Stabilized Dunes in Golden Gate Park, San Francisco
Author(s) -
Amundson Ronald G.,
Tremback Brian
Publication year - 1989
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/sssaj1989.03615995005300060031x
Subject(s) - soil water , vegetation (pathology) , eucalyptus , sand dune stabilization , evergreen , environmental science , myrtaceae , geology , botany , chemistry , soil science , environmental chemistry , biology , geomorphology , medicine , pathology
This paper reports the changes in soil properties that have occurred since vegetation was established on unstabilized dunes approximately a century ago in Golden Gate Park, San Francisco, CA. The static and dynamic soil properties under artificially established eucalyptus ( Eucalyptus globulus Labill.), Monterey pine ( Pinus radiata D. Don), cypress ( Cupressus macrocarpa Hartw. ex. Gord.), as well as native live oak ( Quercus agrifolia Née), were compared with those of an unstabilized dune. The O and A horizon development occurred under all the vegetated sites with differences in the horizon thickness occurring in response to vegetation type. The organic C in the vegetated sites (40 000 to 80 000 kg C ha −1 ) was much greater than in the dune (5000 kg C ha −1 ). The vegetated soils all exhibited severe water repellency in the surface horizons while the dune exhibited none. The oxalate‐extractable Fe in the A horizon of the vegetated soils (1.3–2.3 g kg −1 ) was greater than that in the dune (≈0.9 g kg −1 ) suggesting the formation of organically bound Fe and/or poorly crystalline Fe minerals. Dithionite‐citrate‐bicarbonate extracts suggest the formation of more crystalline forms of Fe oxides in the vegetated sites. Soil temperatures were lower and less variable in the vegetated sites (isomesic regime) than the dune site (mesic or thermic regime), apparently slowing biological activity and reducing the soil CO 2 contents relative to the dune. Total soil respiration in the vegetated soils (350–400 mg CO 2 m −2 h −1 ) was slightly greater than in the dune (300 mg CO 2 m −2 h −1 ), which lacked any appreciable surface litter undergoing decomposition.