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Water‐Holding Characteristics of Metasedimentary Rock in Selected Forest Ecosystems in Southwestern Oregon

1996; Wiley; Volume: 60; Issue: 5 Linguagem: Inglês

10.2136/sssaj1996.03615995006000050042x

1435-0661

Maciej A. Zwieniecki, Michael Newton,

Soil erosion and sediment transport

Abstract On sites characterized by shallow soil in semiarid climates, lack of bedrock description may lead to underestimates of total storage capacity of water available for plants, and therefore of potential site productivity. Sample rocks from southwestern Oregon soil‐rock profiles excavated beneath typical forest plant communities were examined for pore volume distribution by means of mercury intrusion porosimetry and oversolution equilibrium. Four ranges of pore size were distinguished: gravitational water, available water content (AWC), slowly available water (SAW), and nonavailable water. Pore volume for AWC and SAW was associated with bulk density and in low density rock, was 20% of volume. Results suggest that metasedimentary rock has the potential to be a major reservoir of plant available water in semiarid climates.