Summary: Plant and Soil 205: 1324, 1998.
© 1998 Kluwer Academic Publishers. Printed in the Netherlands.
Water use by woody plants on contrasting soils in a savanna parkland:
assessment with 2
H and 18
A.J. Midwood1, T.W. Boutton, S.R. Archer and S.E. Watts2
Department of Rangeland Ecology and Management, Texas A&M University, College Station, TX 77843-2126,
USA. 1Present address: Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK.
2Present address: School of Natural Resources, The Ohio State University, 2021 Coffey Road, Columbus, OH
Received 22 December 1997. Accepted in revised form 10 August 1998
Key words: argillic horizon, deuterium, hydrology, oxygen-18, plant water uptake, root distribution
In savanna parklands of southern Texas, patches of grassland and `discrete clusters' of small trees and shrubs occur
on sandy loam surface soils underlain by an argillic horizon (claypan) at 40 cm. Large trees and shrubs in `groves'
occur on deep (2 m) sandy loam soils without an argillic horizon. 2H and 18O of rainfall, groundwater, and soil
and plant water were measured to: (1) determine if coexistence in woody patches occurs via vertical stratification
of soil water uptake; (2) document differences in plant water acquisition on contrasting soil types; and (3) evaluate