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Title: Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands

Abstract

Ecological studies of soil moisture, plant water uptake, and community composition in semiarid regions have focused on differences with depth in the soil profile, yet there are many reasons to expect that moisture also varies with the presence or absence of woody vegetation. Plant and soil moisture relationships for three dominant species in a semiarid woodland, Bouteloua gracilis, Juniperus monosperma, and Pinus edulis, were studied for 1.5 years. Soil moisture varied by type of plant cover as well as by depth. Plant water potential and conductance differed among species and was related to spatial variability in soil moisture. Water potential for blue grama was most correlated with soil moisture in the 0-15 cm layer of intercanopies; juniper water potential was highly correlated with soil moisture in the 0-15 cm layer beneath tree canopies of either species, and pinyon water potential was only weakly correlated with soil moisture in the 15-30 cm depth interval beneath pinyons. Pinyons had consistently greater maximum conductance rates than junipers, even though pinyon conductance was more sensitive to reductions in soil moisture. The results from this study indicate that horizontal differences in the soil moisture profile associated with type of plant cover may be as importantmore » as differences in depth for predicting plant-water relationships. A simple model was hypothesized for predicting community composition of three lifeforms: Herbaceous plants, shallow-rooted woody plants, and deeper-rooted woody plants. Distributions of roots of each lifeform and plant-available water were defined with respect to four soil compartments that distinguish upper vs. lower and canopy vs. intercanopy soil regions. The model predicts that multiple combinations of herbaceous and woody biomass can exist at a site and was qualitatively consistent with field data from a climatic gradient.« less

Authors:
Publication Date:
Research Org.:
Colorado State Univ., Fort Collins, CO (United States). Dept. of Radiological Health Science
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10183916
Report Number(s):
LA-SUB-94-110
ON: DE94019141; TRN: 94:008451
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis of Philosophy; PBD: Fal 1993
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; MOISTURE; STORAGE; UPTAKE; PLANTS; WATER USE; ROOTS; DEPTH; ARID LANDS; FORESTS; SOILS; CANOPIES; PINES; CEDARS; GRAMINEAE; 550500; 540220; METABOLISM; CHEMICALS MONITORING AND TRANSPORT

Citation Formats

Breshears, D D. Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands. United States: N. p., 1993. Web.
Breshears, D D. Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands. United States.
Breshears, D D. Fri . "Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands". United States.
@article{osti_10183916,
title = {Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands},
author = {Breshears, D D},
abstractNote = {Ecological studies of soil moisture, plant water uptake, and community composition in semiarid regions have focused on differences with depth in the soil profile, yet there are many reasons to expect that moisture also varies with the presence or absence of woody vegetation. Plant and soil moisture relationships for three dominant species in a semiarid woodland, Bouteloua gracilis, Juniperus monosperma, and Pinus edulis, were studied for 1.5 years. Soil moisture varied by type of plant cover as well as by depth. Plant water potential and conductance differed among species and was related to spatial variability in soil moisture. Water potential for blue grama was most correlated with soil moisture in the 0-15 cm layer of intercanopies; juniper water potential was highly correlated with soil moisture in the 0-15 cm layer beneath tree canopies of either species, and pinyon water potential was only weakly correlated with soil moisture in the 15-30 cm depth interval beneath pinyons. Pinyons had consistently greater maximum conductance rates than junipers, even though pinyon conductance was more sensitive to reductions in soil moisture. The results from this study indicate that horizontal differences in the soil moisture profile associated with type of plant cover may be as important as differences in depth for predicting plant-water relationships. A simple model was hypothesized for predicting community composition of three lifeforms: Herbaceous plants, shallow-rooted woody plants, and deeper-rooted woody plants. Distributions of roots of each lifeform and plant-available water were defined with respect to four soil compartments that distinguish upper vs. lower and canopy vs. intercanopy soil regions. The model predicts that multiple combinations of herbaceous and woody biomass can exist at a site and was qualitatively consistent with field data from a climatic gradient.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1993},
month = {12}
}

Thesis/Dissertation:
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