Prescribed burning effects on soil physical properties and soil water repellency in a steep chaparral watershed, southern California, USA

Chaparral watersheds associated with Mediterranean-type climate are distributed over five regions of the world. Because brushland soils are often shallow with low water holding capacities, and are on slopes prone to erosion, disturbances such as fire can adversely affect their physical properties. F...

Full description

Saved in:
Bibliographic Details
Published in:Geoderma 2006-02, Vol.130 (3), p.284-298
Main Authors: Hubbert, K.R., Preisler, H.K., Wohlgemuth, P.M., Graham, R.C., Narog, M.G.
Format: Article
Language:English
Subjects:
Agronomy. Soil science and plant productions
Biological and medical sciences
Chaparral
Earth sciences
Earth, ocean, space
Exact sciences and technology
Fundamental and applied biological sciences. Psychology
Prescribed fire
Soil properties
Soils
Surficial geology
Water infiltration models
Water repellency
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Chaparral watersheds associated with Mediterranean-type climate are distributed over five regions of the world. Because brushland soils are often shallow with low water holding capacities, and are on slopes prone to erosion, disturbances such as fire can adversely affect their physical properties. Fire can also increase the spatial coverage of soil water repellency, reducing infiltration, and, in turn, increasing overland flow and subsequent erosion. We studied the impacts of fire on soil properties by collecting data before and after a prescribed burn conducted during Spring 2001 on the San Dimas Experimental Forest, southern California. The fire removed the litter layer and destroyed the weak surface soil structure; leaving a thin band of ash and char on top of, and mixed in with, an unstable, granular soil of loose consistency. Median litter thickness and clay content were significantly decreased after fire while soil bulk density increased. At 7 d post-fire, soil surface repellency in the watershed was significantly higher than prior to the burn. At 76 d post-fire, surface soil water repellency was returning to near pre-fire values. At the 2 and 4 cm depths, 7 d post-fire soil repellency was also significantly higher than pre-fire, however, conditions at 76 d post-fire were similar to pre-fire values. Variability in soil water repellency between replicates within a given 15 × 15 cm site was as large as the variability seen between sites over the 1.28 ha watershed. The increase in post-fire persistence of water repellency was largest beneath ceanothus ( Ceanothus crassifolius) as compared to a small increase beneath chamise ( Adenostoma fasciculatum). However, pre-fire persistence was higher under chamise than for ceanothus. Post-fire changes to soil properties may increase the watershed hydrologic response, however the mosaic distribution of water repellency may lead to a less severe increase in hydrologic response than might be expected for a spatially more homogenous increase in repellency.
ISSN:0016-7061
1872-6259
DOI:10.1016/j.geoderma.2005.02.001