Partitioning of evapotranspiration and its relation to carbon dioxide exchange in a Chihuahuan Desert shrubland

Authors

Russell L. Scott, USDA-ARS
Travis E. Huxman, University of Arizona
William L. Cable, USDA-ARS
William E. Emmerich, USDA-ARS

Document Type

Article

Date of this Version

2006

Comments

Published in Hydrological Process. 20, 3227–3243 (2006).

Abstract

Key to evaluating the consequences of woody plant encroachment on water and carbon cycling in semiarid ecosystems is a mechanistic understanding of how biological and non-biological processes influence water loss to the atmosphere. To better understand how precipitation is partitioned into the components of evapotranspiration (bare-soil evaporation and plant transpiration) and their relationship to plant uptake of carbon dioxide (CO₂) as well as ecosystem respiratory efflux, we measured whole plant transpiration, evapotranspiration, and CO₂ fluxes over the course of a growing season at a semiarid Chihuahuan Desert shrubland site in south-eastern Arizona. Whole plant transpiration was measured using the heat balance sap-flow method, while evapotranspiration and net ecosystem exchange (NEE) of CO₂ were quantified using the Bowen ratio technique.