Investigation of soil erosion from bare steep slopes of the humid tropic Philippines

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Title Investigation of soil erosion from bare steep slopes of the humid tropic Philippines
Author Prebitero, A. L.; Rose, Calvin Wyatt; Yu, Bofu; Ciesiolka, C.A.A.; Coughlan, K.J.; Fentie, B.
Journal Name Earth Interactions
Year Published 2005
Place of publication USA
Publisher American Geophysical Union
Abstract At the Visayas State College of Agriculture (ViSCA) on the island of Leyte in the Philippines, hydrologic and soil-loss measurements were recorded for 32 erosion events over 3 yr on three 12-m-long bare soil plots with slopes of approximately 50%, 60%, and 70%. Measurements included rainfall and runoff rates at 1-min intervals, total soil lost per event from the plot, rill details when observed after an erosion event, and soil settling-velocity characteristics. Storm events are characterized by high rainfall rates but quite low rates of runoff, because of the consistently high infiltration rate of the stable clay soil (an Oxic Dystropept). Both observation and modeling indicated that overland flow is commonly so shallow that much of the soil surface is likely to be unsubmerged. For the 70% slope plot, half the events recorded mean sediment concentrations from 100 to 570 kg m−3. A somewhat constant hydrologic lag between rainfall and runoff is used to estimate a Manning's roughness coefficient n of about 0.1 m−1/3 s, a value used to estimate velocity of overland flow. Possible effects of shallow flows and high sediment concentrations on existing erosion theory are investigated theoretically but are found to have only minor effects for the ViSCA dataset. A soil erodibility parameter β was evaluated for the data whenever rilling was recorded following an erosion event. The values of β indicate that, except for events with higher stream powers, other erosion processes in addition to overland flow could have contributed to soil loss from erosion plots in a significant number of events.
Peer Reviewed Yes
Published Yes
Publisher URI http://earthinteractions.org/
Alternative URI http://dx.doi.org/10.1175/EI121.1
Copyright Statement Copyright 2005 American Geophysical Union. The attached file is reproduced here in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Volume 9
Issue Number 5
Page from 1
Page to 30
ISSN 1087-3562
Date Accessioned 2006-02-28
Language en_AU
Faculty Faculty of Environmental Sciences
Subject PRE2009-Conservation
URI http://hdl.handle.net/10072/4379
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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