HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Williamson, T. N. Articles by Shouse, P. J. Search for Related Content PubMed Articles by Williamson, T. N. Articles by Shouse, P. J. GeoRef GeoRef Citation Agricola Articles by Williamson, T. N. Articles by Shouse, P. J. Related Collections Watershed and Landscape Processes

ORIGINAL RESEARCH

Regolith Water in Zero-Order Chaparral and Perennial Grass Watersheds Four Decades after Vegetation Conversion

^a Dep. of Geosciences, Univ. of the Pacific, Stockton, CA 95211
^b Los Alamos National Lab., MS J495 EES-2: Earth and Environmental Sciences Division, Los Alamos, NM 87545
^c Dep. of Environmental Science, Univ. of California, Riverside, CA 92521
^d USDA-ARS, U.S. Salinity Lab., 450 W. Big Springs Rd., Riverside, CA 92507
^* Corresponding author (twilliam{at}pacific.edu)

Received 14 August 2003.

In 1960, areas of chaparral were converted to perennial grass after a fire burned most of the San Dimas Experimental Forest in southern California. This conversion provided an opportunity to compare regolith moisture patterns of zero-order watersheds under native chaparral with those under nonnative veldt grass (Ehrharta calycina Sm.). We collected data as a function of vegetation type and watershed element to test the hypothesis that conversion from chaparral to grass altered water distribution in the vadose zone as a result of changes in the physical environment, including rooting depth and soil horizonation. Patterns in vadose zone water distribution during the dry season, including soil water potential and residual flux, were significantly different in converted areas, reflecting the different rooting habits of the two vegetation types. In chaparral areas, there was no significant change in soil water potential between the surface and the 150-cm depth; soil water potential was consistently below –1.5 MPa, reflecting the extensive root system. In grass areas, soil water potential was most negative close to the surface, where grass roots were most abundant. Plant available water was present below the 100-cm depth, suggesting that recharge to groundwater may occur under grass in average or wetter years. Under both vegetation types, the largest differences in residual water fluxes were near the soil–weathered rock contact. However, there was a significant relation between minor differences in fluxes and soil horizon boundaries, confirming the effects of vegetation conversion on soil properties and vadose zone soil water.

Abbreviations: SDEF, San Dimas Experimental Forest

This article has been cited by other articles:

				B. D. Newman and R. C. Graham Species-Level Impacts on Chaparral Root Zone Hydrology Vadose Zone J., August 13, 2008; 7(3): 1110 - 1118. [Abstract] [Full Text] [PDF]

				J. E. Schoonover, B. G. Lockaby, and B. S. Helms Impacts of Land Cover on Stream Hydrology in the West Georgia Piedmont, USA J. Environ. Qual., October 27, 2006; 35(6): 2123 - 2131. [Abstract] [Full Text] [PDF]

				Y. A. Wood, T. Meixner, P. J. Shouse, and E. B. Allen Altered Ecohydrologic Response Drives Native Shrub Loss under Conditions of Elevated Nitrogen Deposition J. Environ. Qual., January 3, 2006; 35(1): 76 - 92. [Abstract] [Full Text] [PDF]